WorldWideScience

Sample records for variable area nozzle

  1. Shape memory alloy actuation for a variable area fan nozzle

    Science.gov (United States)

    Rey, Nancy; Tillman, Gregory; Miller, Robin M.; Wynosky, Thomas; Larkin, Michael J.; Flamm, Jeffrey D.; Bangert, Linda S.

    2001-06-01

    The ability to control fan nozzle exit area is an enabling technology for next generation high-bypass-ratio turbofan engines. Performance benefits for such designs are estimated at up to 9% in thrust specific fuel consumption (TSFC) relative to current fixed-geometry engines. Conventionally actuated variable area fan nozzle (VAN) concepts tend to be heavy and complicated, with significant aircraft integration, reliability and packaging issues. The goal of this effort was to eliminate these undesirable features and formulate a design that meets or exceeds leakage, durability, reliability, maintenance and manufacturing cost goals. A Shape Memory Alloy (SMA) bundled cable actuator acting to move an array of flaps around the fan nozzle annulus is a concept that meets these requirements. The SMA bundled cable actuator developed by the United Technologies Corporation (Patents Pending) provides significant work output (greater than 2200 in-lb per flap, through the range of motion) in a compact package and minimizes system complexity. Results of a detailed design study indicate substantial engine performance, weight, and range benefits. The SMA- based actuation system is roughly two times lighter than a conventional mechanical system, with significant aircraft direct operating cost savings (2-3%) and range improvements (5-6%) relative to a fixed-geometry nozzle geared turbofan. A full-scale sector model of this VAN system was built and then tested at the Jet Exit Test Facility at NASA Langley to demonstrate the system's ability to achieve 20% area variation of the nozzle under full scale aerodynamic loads. The actuator exceeded requirements, achieving repeated actuation against full-scale loads representative of typical cruise as well as greater than worst-case (ultimate) aerodynamic conditions. Based on these encouraging results, work is continuing with the goal of a flight test on a C-17 transport aircraft.

  2. Altitude Performance Characteristics of Tail-pipe Burner with Variable-area Exhaust Nozzle

    Science.gov (United States)

    Jansen, Emmert T; Thorman, H Carl

    1950-01-01

    An investigation was conducted in the NACA Lewis altitude wind tunnel to determine effect of altitude and flight Mach number on performance of tail-pipe burner equipped with variable-area exhaust nozzle and installed on full-scale turbojet engine. At a given flight Mach number, with constant exhaust-gas and turbine-outlet temperatures, increasing altitude lowered the tail-pipe combustion efficiency and raised the specific fuel consumption while the augmented thrust ratio remained approximately constant. At a given altitude, increasing flight Mach number raised the combustion efficiency and augmented thrust ratio and lowered the specific fuel consumption.

  3. Dynamic Analysis for a Geared Turbofan Engine with Variable Area Fan Nozzle

    Science.gov (United States)

    Csank, Jeffrey T.; Thomas, George L.

    2017-01-01

    Aggressive design goals have been set for future aero-propulsion systems with regards to fuel economy, noise, and emissions. To meet these challenging goals, advanced propulsion concepts are being explored and current operating margins are being re-evaluated to find additional concessions that can be made. One advanced propulsion concept being evaluated is a geared turbofan with a variable area fan nozzle (VAFN), developed by NASA. This engine features a small core, a fan driven by the low pressure turbine through a reduction gearbox, and a shape memory alloy (SMA)-actuated VAFN. The VAFN is designed to allow both a small exit area for efficient operation at cruise, while being able to open wider at high power conditions to reduce backpressure on the fan and ensure a safe level of stall margin is maintained. The VAFN is actuated via a SMA-based system instead of a conventional system to decrease overall weight of the system, however, SMA-based actuators respond relatively slowly, which introduces dynamic issues that are investigated in this work. This paper describes both a control system designed specifically for issues associated with SMAs, and dynamic analysis of the geared turbofan VAFN with the SMA actuators. Also, some future recommendations are provided for this type of propulsion system.

  4. Arcjet nozzle area ratio effects

    Science.gov (United States)

    Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

    1990-01-01

    An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

  5. Arcjet Nozzle Area Ratio Effects

    Science.gov (United States)

    Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

    1990-01-01

    An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

  6. A fundamental study of a variable critical nozzle flow

    International Nuclear Information System (INIS)

    Kim, Jea Hyung; Kim, Heuy Dong; Park, Kyung Am

    2003-01-01

    The mass flow rate of gas flow through critical nozzle depends on the nozzle supply conditions and the cross-sectional area at the nozzle throat. In order that the critical nozzle can be operated at a wide range of supply conditions, the nozzle throat diameter should be controlled to change the flow passage area. This can be achieved by means of a variable critical nozzle. In the present study, both experimental and computational works are performed to develop variable critical nozzle. A cone-cylinder with a diameter of d is inserted into conventional critical nozzle. It can move both upstream and downstream, thereby changing the cross-sectional area of the nozzle throat. Computational work using the axisymmetric, compressible Navier-Stokes equations is carried out to simulate the variable critical nozzle flow. An experiment is performed to measure the mass flow rate through variable critical nozzle. The present computational results are in close agreement with measured ones. The boundary layer displacement and momentum thickness are given as a function of Reynolds number. An empirical equation is obtained to predict the discharge coefficient of variable critical nozzle

  7. Altitude Performance Characteristics of Turbojet-engine Tail-pipe Burner with Variable-area Exhaust Nozzle Using Several Fuel Systems and Flame Holders

    Science.gov (United States)

    Johnson, Lavern A; Meyer, Carl L

    1950-01-01

    A tail-pipe burner with a variable-area exhaust nozzle was investigated. From five configurations a fuel-distribution system and a flame holder were selected. The best configuration was investigated over a range of altitudes and flight Mach numbers. For the best configuration, an increase in altitude lowered the augmented thrust ratio, exhaust-gas total temperature, and tail-pipe combustion efficiency, and raised the specific fuel consumption. An increase in flight Mach number raised the augmented thrust ratio but had no apparent effect on exhaust-gas total temperature, tail-pipe combustion efficiency, or specific fuel consumption.

  8. Turbocharger with variable nozzle having vane sealing surfaces

    Science.gov (United States)

    Arnold, Philippe [Hennecourt, FR; Petitjean, Dominique [Julienrupt, FR; Ruquart, Anthony [Thaon les Vosges, FR; Dupont, Guillaume [Thaon les Vosges, FR; Jeckel, Denis [Thaon les Vosges, FR

    2011-11-15

    A variable nozzle for a turbocharger includes a plurality of vanes rotatably mounted on a nozzle ring and disposed in a nozzle flow path defined between the nozzle ring and an opposite nozzle wall. Either or both of the faces of the nozzle ring and nozzle wall include(s) at least one step that defines sealing surfaces positioned to be substantially abutted by airfoil surfaces of the vanes in the closed position of the vanes and to be spaced from the airfoil surfaces in positions other than the closed position. This substantial abutment between the airfoil surfaces and the sealing surfaces serves to substantially prevent exhaust gas from leaking past the ends of the airfoil portions. At the same time, clearances between the nozzle ring face and the end faces of the airfoil portions can be sufficiently large to prevent binding of the vanes under all operating conditions.

  9. Injection and spray characteristics of a variable orifice nozzle applied the jerk type fuel injection pump for DI diesel engine; Jerk shiki nenryo funsha pump wo mochiita kahen funko nozzle no funsha funmu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T; Matsui, K; Iwasaki, T; Kobayashi, T [Zexel Corp., Tokyo (Japan); Matsumoto, Y [The University of Tokyo, Tokyo (Japan)

    1997-10-01

    A Variable Orifice Nozzle (VON) by changing a cross-sectional area of the nozzle injection hole, for improving a rate of injection and injection duration, has been developed to study its injection and spray characteristics. The nozzle geometry was optimized to analyze a nozzle internal flow by computational method. Results show that, injection and spray pattern responded to the nozzle orifice cross-sectional area which is changing larger to smaller in the part load range. This results suggest to contribute a combustion improvement which decreasing NOx and soot. 14 refs., 10 figs.

  10. Variable volume combustor with pre-nozzle fuel injection system

    Science.gov (United States)

    Keener, Christopher Paul; Johnson, Thomas Edward; McConnaughhay, Johnie Franklin; Ostebee, Heath Michael

    2016-09-06

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of fuel nozzles, a pre-nozzle fuel injection system supporting the fuel nozzles, and a linear actuator to maneuver the fuel nozzles and the pre-nozzle fuel injection system.

  11. Variable volume combustor with aerodynamic fuel flanges for nozzle mounting

    Science.gov (United States)

    McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward; Ostebee, Heath Michael

    2016-09-20

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a number of support struts supporting the fuel nozzles and for providing the flow of fuel therethrough. The fuel injection system also may include a number of aerodynamic fuel flanges connecting the micro-mixer fuel nozzles and the support struts.

  12. Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

    Science.gov (United States)

    Connolly, Joseph W.; Friedlander, David; Kopasakis, George

    2015-01-01

    This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

  13. Experimental aerodynamic and acoustic model testing of the Variable Cycle Engine (VCE) testbed coannular exhaust nozzle system

    Science.gov (United States)

    Nelson, D. P.; Morris, P. M.

    1980-01-01

    Aerodynamic performance and jet noise characteristics of a one sixth scale model of the variable cycle engine testbed exhaust system were obtained in a series of static tests over a range of simulated engine operating conditions. Model acoustic data were acquired. Data were compared to predictions of coannular model nozzle performance. The model, tested with an without a hardwall ejector, had a total flow area equivalent to a 0.127 meter (5 inch) diameter conical nozzle with a 0.65 fan to primary nozzle area ratio and a 0.82 fan nozzle radius ratio. Fan stream temperatures and velocities were varied from 422 K to 1089 K (760 R to 1960 R) and 434 to 755 meters per second (1423 to 2477 feet per second). Primary stream properties were varied from 589 to 1089 K (1060 R to 1960 R) and 353 to 600 meters per second (1158 to 1968 feet per second). Exhaust plume velocity surveys were conducted at one operating condition with and without the ejector installed. Thirty aerodynamic performance data points were obtained with an unheated air supply. Fan nozzle pressure ratio was varied from 1.8 to 3.2 at a constant primary pressure ratio of 1.6; primary pressure ratio was varied from 1.4 to 2.4 while holding fan pressure ratio constant at 2.4. Operation with the ejector increased nozzle thrust coefficient 0.2 to 0.4 percent.

  14. Thrust distribution for attitude control in a variable thrust propulsion system with four ACS nozzles

    Science.gov (United States)

    Lim, Yeerang; Lee, Wonsuk; Bang, Hyochoong; Lee, Hosung

    2017-04-01

    A thrust distribution approach is proposed in this paper for a variable thrust solid propulsion system with an attitude control system (ACS) that uses a reduced number of nozzles for a three-axis attitude maneuver. Although a conventional variable thrust solid propulsion system needs six ACS nozzles, this paper proposes a thrust system with four ACS nozzles to reduce the complexity and mass of the system. The performance of the new system was analyzed with numerical simulations, and the results show that the performance of the system with four ACS nozzles was similar to the original system while the mass of the whole system was simultaneously reduced. Moreover, a feasibility analysis was performed to determine whether a thrust system with three ACS nozzles is possible.

  15. The Effect of Variable Gravity on the Cooling Performance of a 16-Nozzle Spray Array

    National Research Council Canada - National Science Library

    Elston, Levi J; Yerkes, Kirk L; Thomas, Scott K; McQuillen, John

    2008-01-01

    The objective of this thesis was to investigate the cooling performance of a 16-nozzle spray array, using FC-72 as the working fluid, in variable gravity conditions with additional emphasis on fluid...

  16. Acoustic and aerodynamic performance investigation of inverted velocity profile coannular plug nozzles. [variable cycle engines

    Science.gov (United States)

    Knott, P. R.; Blozy, J. T.; Staid, P. S.

    1981-01-01

    The results of model scale parametric static and wind tunnel aerodynamic performance tests on unsuppressed coannular plug nozzle configurations with inverted velocity profile are discussed. The nozzle configurations are high-radius-ratio coannular plug nozzles applicable to dual-stream exhaust systems typical of a variable cycle engine for Advanced Supersonic Transport application. In all, seven acoustic models and eight aerodynamic performance models were tested. The nozzle geometric variables included outer stream radius ratio, inner stream to outer stream ratio, and inner stream plug shape. When compared to a conical nozzle at the same specific thrust, the results of the static acoustic tests with the coannular nozzles showed noise reductions of up to 7 PNdB. Extensive data analysis showed that the overall acoustic results can be well correlated using the mixed stream velocity and the mixed stream density. Results also showed that suppression levels are geometry and flow regulation dependent with the outer stream radius ratio, inner stream-to-outer stream velocity ratio and inner stream velocity ratio and inner stream plug shape, as the primary suppression parameters. In addition, high-radius ratio coannular plug nozzles were found to yield shock associated noise level reductions relative to a conical nozzle. The wind tunnel aerodynamic tests showed that static and simulated flight thrust coefficient at typical takeoff conditions are quite good - up to 0.98 at static conditions and 0.974 at a takeoff Mach number of 0.36. At low inner stream flow conditions significant thrust loss was observed. Using an inner stream conical plug resulted in 1% to 2% higher performance levels than nozzle geometries using a bent inner plug.

  17. Numerical investigation of the variable nozzle effect on the mixed flow turbine performance characteristics

    Science.gov (United States)

    Meziri, B.; Hamel, M.; Hireche, O.; Hamidou, K.

    2016-09-01

    There are various matching ways between turbocharger and engine, the variable nozzle turbine is the most significant method. The turbine design must be economic with high efficiency and large capacity over a wide range of operational conditions. These design intents are used in order to decrease thermal load and improve thermal efficiency of the engine. This paper presents an original design method of a variable nozzle vane for mixed flow turbines developed from previous experimental and numerical studies. The new device is evaluated with a numerical simulation over a wide range of rotational speeds, pressure ratios, and different vane angles. The compressible turbulent steady flow is solved using the ANSYS CFX software. The numerical results agree well with experimental data in the nozzleless configuration. In the variable nozzle case, the results show that the turbine performance characteristics are well accepted in different open positions and improved significantly in low speed regime and at low pressure ratio.

  18. Soil variability in mountain areas

    OpenAIRE

    Zanini, E.; Freppaz, M.; Stanchi, S.; Bonifacio, E.; Egli, M.

    2015-01-01

    The high spatial variability of soils is a relevant issue at local and global scales, and determines the complexity of soil ecosystem functions and services. This variability derives from strong dependencies of soil ecosystems on parent materials, climate, relief and biosphere, including human impact. Although present in all environments, the interactions of soils with these forming factors are particularly striking in mountain areas.

  19. Investigation on the effects of geometric variables on the residual stresses and PWSCC growth in the RPV BMI penetration nozzles

    International Nuclear Information System (INIS)

    Kim, Jong Sung; Ra, Myoung Soo; Lee, Kyoung Soo

    2015-01-01

    This study investigated the effects of various geometric variables on the residual stresses and PWSCC growth of RPV BMI penetration nozzles. An FE residual stress analysis procedure was developed and validated from the viewpoint of FFS assessment. The validated FE residual stress analysis procedure and the PWSCC growth assessment procedure in the ASME B and PV Code, Sec.XI were applied to the BMI penetration nozzles with specified ranges of the geometric variables. The total stresses at steady state during normal operation including welding residual stresses increase with increasing inclination angle of the BMI nozzles, and with tilt angle, depth, and root width of the J-groove weld. The lifetime from the assumed initial crack to the acceptance criteria according to the ASME B and PV Code, Sec.XI also decreases under these conditions. The total stresses decrease and the lifetime increases with increasing nozzle thickness, but outer radius of the BMI nozzles has an insignificant effect on both of these factors.

  20. Fluiddynamic effects in the fuel element top nozzle area during refilling and reflooding

    International Nuclear Information System (INIS)

    Hawighorst, A.; Kroening, H.; Mewes, D.; Spatz, R.; Mayinger, F.

    1985-01-01

    During the refilling and reflooding phase following a hypothetical loss of coolant accident in lightwater cooled nuclear reactors, there will be countercurrent flow between discharging steam and the feed of emergency core cooling water. It was the objective of this research project to contribute to a better physical understanding of the fluiddynamic processes in the area of the fuel element top nozzle and so to improve emergency core cooling calculations. Therefore, experimental and theoretical investigations about the entrainment and countercurrent behaviour of gas/liquid flows have been implemented within this project. Fluiddynamic processes in the fuel element top nozzle area were simulated during the reflooding and refilling phase. Based on special internals as single and multiple-hole orifices, basic phenomena of fluidynamics were studied first with air-water. Subsequently, investigations of the system steam/water were conducted. The reactor geometry was approximated step by step, until a complete reactor fuel assembly top nozzle was constituted. The system pressure was 4.8 bars (abs), in accordance with the conditions in the reactor pressure vessel at the end of the blowdown phase. The water was initially fed in at saturation temperature, then, as a second step, fed in at subcooled condition relative to the steam temperature, in order to be able to study condensation effects as well. First, investigations on gas/liquid countercurrent flows in the fluid system air/water are presented. Then one studies countercurrent flow in the system steam/water, including the investigation of condensation effects. Finally, a detailed description of the research on droplet size determination is given

  1. Improvement on Main/backup Controller Switching Device of the Nozzle Throat Area Control System for a Turbofan Aero Engine

    Science.gov (United States)

    Li, Jie; Duan, Minghu; Yan, Maode; Li, Gang; Li, Xiaohui

    2014-06-01

    A full authority digital electronic controller (FADEC) equipped with a full authority hydro-mechanical backup controller (FAHMBC) is adopted as the nozzle throat area control system (NTACS) of a turbofan aero engine. In order to ensure the switching reliability of the main/backup controller, the nozzle throat area control switching valve was improved from three-way convex desktop slide valve to six-way convex desktop slide valve. Simulation results show that, if malfunctions of FAEDC occur and abnormal signals are outputted from FADEC, NTACS will be seriously influenced by the main/backup controller switching in several working states, while NTACS will not be influenced by using the improved nozzle throat area control switching valve, thus the controller switching process will become safer and smoother and the working reliability of this turbofan aero engine is improved by the controller switching device improvement.

  2. The Effect of Bypass Nozzle Exit Area on Fan Aerodynamic Performance and Noise in a Model Turbofan Simulator

    Science.gov (United States)

    Hughes, Christopher E.; Podboy, Gary, G.; Woodward, Richard P.; Jeracki, Robert, J.

    2013-01-01

    The design of effective new technologies to reduce aircraft propulsion noise is dependent on identifying and understanding the noise sources and noise generation mechanisms in the modern turbofan engine, as well as determining their contribution to the overall aircraft noise signature. Therefore, a comprehensive aeroacoustic wind tunnel test program was conducted called the Fan Broadband Source Diagnostic Test as part of the NASA Quiet Aircraft Technology program. The test was performed in the anechoic NASA Glenn 9- by 15-Foot Low Speed Wind Tunnel using a 1/5 scale model turbofan simulator which represented a current generation, medium pressure ratio, high bypass turbofan aircraft engine. The investigation focused on simulating in model scale only the bypass section of the turbofan engine. The test objectives were to: identify the noise sources within the model and determine their noise level; investigate several component design technologies by determining their impact on the aerodynamic and acoustic performance of the fan stage; and conduct detailed flow diagnostics within the fan flow field to characterize the physics of the noise generation mechanisms in a turbofan model. This report discusses results obtained for one aspect of the Source Diagnostic Test that investigated the effect of the bypass or fan nozzle exit area on the bypass stage aerodynamic performance, specifically the fan and outlet guide vanes or stators, as well as the farfield acoustic noise level. The aerodynamic performance, farfield acoustics, and Laser Doppler Velocimeter flow diagnostic results are presented for the fan and four different fixed-area bypass nozzle configurations. The nozzles simulated fixed engine operating lines and encompassed the fan stage operating envelope from near stall to cruise. One nozzle was selected as a baseline reference, representing the nozzle area which would achieve the design point operating conditions and fan stage performance. The total area change from

  3. Nozzle airfoil having movable nozzle ribs

    Science.gov (United States)

    Yu, Yufeng Phillip; Itzel, Gary Michael

    2002-01-01

    A nozzle vane or airfoil structure is provided in which the nozzle ribs are connected to the side walls of the vane or airfoil in such a way that the ribs provide the requisite mechanical support between the concave side and convex side of the airfoil but are not locked in the radial direction of the assembly, longitudinally of the airfoil. The ribs may be bi-cast onto a preformed airfoil side wall structure or fastened to the airfoil by an interlocking slide connection and/or welding. By attaching the nozzle ribs to the nozzle airfoil metal in such a way that allows play longitudinally of the airfoil, the temperature difference induced radial thermal stresses at the nozzle airfoil/rib joint area are reduced while maintaining proper mechanical support of the nozzle side walls.

  4. Analysis of experiments of the University of Hannover with the Cathare code on fluid dynamic effects in the fuel element top nozzle area during refilling and reflooding

    International Nuclear Information System (INIS)

    Bestion, D.

    1989-11-01

    The CATHARE code is used to calculate the experiment of the University of Hannover concerning the flooding limit at the fuel element top nozzle area. Some qualitative and quantitativ limit at the fuel element top nozzle area. on both the actual fluid dynamics which is observed in the experiments and on the corresponding code behaviour. Shortcomings of the present models are clearly identified. New developments are proposed which should extend the code capabilities

  5. Prototype Morphing Fan Nozzle Demonstrated

    Science.gov (United States)

    Lee, Ho-Jun; Song, Gang-Bing

    2004-01-01

    Ongoing research in NASA Glenn Research Center's Structural Mechanics and Dynamics Branch to develop smart materials technologies for aeropropulsion structural components has resulted in the design of the prototype morphing fan nozzle shown in the photograph. This prototype exploits the potential of smart materials to significantly improve the performance of existing aircraft engines by introducing new inherent capabilities for shape control, vibration damping, noise reduction, health monitoring, and flow manipulation. The novel design employs two different smart materials, a shape-memory alloy and magnetorheological fluids, to reduce the nozzle area by up to 30 percent. The prototype of the variable-area fan nozzle implements an overlapping spring leaf assembly to simplify the initial design and to provide ease of structural control. A single bundle of shape memory alloy wire actuators is used to reduce the nozzle geometry. The nozzle is subsequently held in the reduced-area configuration by using magnetorheological fluid brakes. This prototype uses the inherent advantages of shape memory alloys in providing large induced strains and of magnetorheological fluids in generating large resistive forces. In addition, the spring leaf design also functions as a return spring, once the magnetorheological fluid brakes are released, to help force the shape memory alloy wires to return to their original position. A computerized real-time control system uses the derivative-gain and proportional-gain algorithms to operate the system. This design represents a novel approach to the active control of high-bypass-ratio turbofan engines. Researchers have estimated that such engines will reduce thrust specific fuel consumption by 9 percent over that of fixed-geometry fan nozzles. This research was conducted under a cooperative agreement (NCC3-839) at the University of Akron.

  6. Axisymmetric thrust-vectoring nozzle performance prediction

    International Nuclear Information System (INIS)

    Wilson, E. A.; Adler, D.; Bar-Yoseph, P.Z

    1998-01-01

    Throat-hinged geometrically variable converging-diverging thrust-vectoring nozzles directly affect the jet flow geometry and rotation angle at the nozzle exit as a function of the nozzle geometry, the nozzle pressure ratio and flight velocity. The consideration of nozzle divergence in the effective-geometric nozzle relation is theoretically considered here for the first time. In this study, an explicit calculation procedure is presented as a function of nozzle geometry at constant nozzle pressure ratio, zero velocity and altitude, and compared with experimental results in a civil thrust-vectoring scenario. This procedure may be used in dynamic thrust-vectoring nozzle design performance predictions or analysis for civil and military nozzles as well as in the definition of initial jet flow conditions in future numerical VSTOL/TV jet performance studies

  7. Nozzle seal

    International Nuclear Information System (INIS)

    Herman, R.F.

    1977-01-01

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing members operatively disposed between the outlet nozzle and the hoop. The sealing members are biased against the pressure vessel and the hoop and are connected by a leak restraining member establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel

  8. Nozzle seal

    International Nuclear Information System (INIS)

    Walling, G.A.

    1977-01-01

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing rings operatively disposed between the outlet nozzles and the hoop. The sealing rings connected by flexible members are biased against the pressure vessel and the hoop, establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel. 4 claims, 2 figures

  9. Variability of rainfall over small areas

    Science.gov (United States)

    Runnels, R. C.

    1983-01-01

    A preliminary investigation was made to determine estimates of the number of raingauges needed in order to measure the variability of rainfall in time and space over small areas (approximately 40 sq miles). The literature on rainfall variability was examined and the types of empirical relationships used to relate rainfall variations to meteorological and catchment-area characteristics were considered. Relations between the coefficient of variation and areal-mean rainfall and area have been used by several investigators. These parameters seemed reasonable ones to use in any future study of rainfall variations. From a knowledge of an appropriate coefficient of variation (determined by the above-mentioned relations) the number rain gauges needed for the precise determination of areal-mean rainfall may be calculated by statistical estimation theory. The number gauges needed to measure the coefficient of variation over a 40 sq miles area, with varying degrees of error, was found to range from 264 (10% error, mean precipitation = 0.1 in) to about 2 (100% error, mean precipitation = 0.1 in).

  10. Preliminary study of the primary nozzle position of a supersonic air ejector with a constant-area mixing chamber

    Directory of Open Access Journals (Sweden)

    Kracik Jan

    2017-01-01

    Full Text Available This work aims at investigating the primary nozzle position in a proposed supersonic air ejector device. The ejector is primarily made up of a supersonic primary nozzle, which is located in the axis of the ejector, a suction chamber or secondary stream inlet, a mixing chamber and a diffuser. The ejector design allows to translate the primary nozzle in the axis direction and fix it in a chosen distance from the beginning of the mixing chamber and hence influence the secondary mass flow rate. In a limit case, it is possible to set the nozzle to such a position where no secondary flow occurs. If we ignore the case where no secondary flow occurs, five different nozzle distances have been investigated in this paper. Some cases seem to be alike and there are no significant dissimilarities between them. Courses of relative back-pressure ratio are carried out against the entrainment ratio and transition between on-design and off-design regimes is determined. Measurements of the mixed flow based on the standard ISO 5167 are performed by means of orifice plate method. In addition, a comparison between experiments and simulations performed by Ansys Fluent software is presented in order to indicate further improvements to the numerical model.

  11. Operational analysis of the coupling between a multi-effect distillation unit with thermal vapor compression and a Rankine cycle power block using variable nozzle thermocompressors

    International Nuclear Information System (INIS)

    Ortega-Delgado, Bartolomé; Cornali, Matteo; Palenzuela, Patricia; Alarcón-Padilla, Diego C.

    2017-01-01

    Highlights: •Variable nozzle steam ejectors are used for operation flexibility of MED plants. •The power block breaking points have been investigated by simulations in Thermoflex. •An operational model of the MED-TVC process is developed for part load operation. •Efficiency and fresh water production are studied at nominal and partial loads. -- Abstract: In Multi-Effect Distillation with Thermal Vapor Compression (MED-TVC) plants, fixed steam ejectors are usually designed for constant motive steam pressures. When these distillation units are integrated into Concentrating Solar Power (CSP) plants, the available motive steam pressure is normally lower than the design value (due to the partial load operation of the power cycle under different solar radiation conditions), being the efficiency of the steam ejectors drastically reduced. Also, it has a negative impact on the fresh water production from the desalination plant because of a decrease in the mass flow of the motive steam. All this can be avoided by using variable nozzle steam ejectors, which can adjust the mass flow rate of steam according to the variable pressure so that they are always operating with the maximum efficiency and therefore they can maintain the freshwater production of the desalination plant near to the nominal value. This work presents a study of the coupling between CSP plants and MED-TVC units using variable nozzle steam ejectors in a wide range of operating conditions (on and off-design). For this purpose, simulations of a Rankine cycle power block in a typical commercial CSP plant have been firstly performed at different thermal loads to investigate the operational limits that allow keeping the motive steam mass flow rates constant. Then, the efficiency and fresh water production of an MED-TVC unit coupled to the different extractions available at the CSP plant have been studied in a wide range of operating conditions, covering both nominal and partial loads. To this end, an

  12. Fuel nozzle assembly

    Science.gov (United States)

    Johnson, Thomas Edward [Greer, SC; Ziminsky, Willy Steve [Simpsonville, SC; Lacey, Benjamin Paul [Greer, SC; York, William David [Greer, SC; Stevenson, Christian Xavier [Inman, SC

    2011-08-30

    A fuel nozzle assembly is provided. The assembly includes an outer nozzle body having a first end and a second end and at least one inner nozzle tube having a first end and a second end. One of the nozzle body or nozzle tube includes a fuel plenum and a fuel passage extending therefrom, while the other of the nozzle body or nozzle tube includes a fuel injection hole slidably aligned with the fuel passage to form a fuel flow path therebetween at an interface between the body and the tube. The nozzle body and the nozzle tube are fixed against relative movement at the first ends of the nozzle body and nozzle tube, enabling the fuel flow path to close at the interface due to thermal growth after a flame enters the nozzle tube.

  13. Variable stator radial turbine

    Science.gov (United States)

    Rogo, C.; Hajek, T.; Chen, A. G.

    1984-01-01

    A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.

  14. Investigation of turbines for driving supersonic compressors II : performance of first configuration with 2.2 percent reduction in nozzle flow area / Warner L. Stewart, Harold J. Schum, Robert Y. Wong

    Science.gov (United States)

    Stewart, Warner L; Schum, Harold J; Wong, Robert Y

    1952-01-01

    The experimental performance of a modified turbine for driving a supersonic compressor is presented and compared with the performance of the original configuration to illustrate the effect of small changes in the ratio of nozzle-throat area to rotor-throat area. Performance is based on the performance of turbines designed to operate with both blade rows close to choking. On the basis of the results of this investigation, the ratio of areas is concluded to become especially critical in the design of turbines such as those designed to drive high-speed, high-specific weight-flow compressors where the turbine nozzles and rotor are both very close to choking.

  15. Cross-talk effect in electrostatic based capillary array nozzles

    International Nuclear Information System (INIS)

    Choi, Kyung Hyun; Rahman, Khalid; Khan, Arshad; Kim, Dong Soo

    2011-01-01

    Electrohydrodynamic printing is a promising technique for printed electronics application. Most researchers working in this field are using a single nozzle configuration. However, for large area printing a multi-nozzle setup will be required for time and cost effective process. In this paper the influence of electric field and flow-rate on jetting angle on multi-nozzle array has been investigated experimentally. A three nozzle setup has been used in a linear array by using glass capillary as a nozzle with independent voltage applied on each nozzle and independent ink supply. The experiments are performed by changing the nozzle to nozzle gap and the effect on the jetting angle has been investigated. It has been observed that by increasing the applied voltage the jetting angle also increases at fixed flow-rate. In case of increasing the flow-rate, the jetting angle first increases with increase in flow-rate, but as the flow-rate increases at certain level the jetting angle decreases; moreover, at a high flow-rate the cone-jet length starts increasing. Numerical simulation has been performed to have a better understanding of the electric-field with respect to jetting angles. The influence of one nozzle on another nozzle is also investigated by operating the nozzle independently by using different operating cases. The cross-talk effect is also minimized by reducing the nozzle diameter. At 250 μm nozzle diameter the cross-talk effect was negligible for 5 mm nozzle-to-nozzle gap. This study will help in better understanding of the interaction between different nozzles in multi-nozzle cases and better design of the multi-nozzle system by minimizing the effects of adjacent nozzles for multi-nozzle electrohydrodynamic printing system

  16. Equivalent nozzle in thermomechanical problems

    International Nuclear Information System (INIS)

    Cesari, F.

    1977-01-01

    When analyzing nuclear vessels, it is most important to study the behavior of the nozzle cylinder-cylinder intersection. For the elastic field, this analysis in three dimensions is quite easy using the method of finite elements. The same analysis in the non-linear field becomes difficult for designs in 3-D. It is therefore necessary to resolve a nozzle in two dimensions equivalent to a 3-D nozzle. The purpose of the present work is to find an equivalent nozzle both with a mechanical and thermal load. This has been achieved by the analysis in three dimensions of a nozzle and a nozzle cylinder-sphere intersection, of a different radius. The equivalent nozzle will be a nozzle with a sphere radius in a given ratio to the radius of a cylinder; thus, the maximum equivalent stress is the same in both 2-D and 3-D. The nozzle examined derived from the intersection of a cylindrical vessel of radius R=191.4 mm and thickness T=6.7 mm with a cylindrical nozzle of radius r=24.675 mm and thickness t=1.350 mm, for which the experimental results for an internal pressure load are known. The structure was subdivided into 96 finite, three-dimensional and isoparametric elements with 60 degrees of freedom and 661 total nodes. Both the analysis with a mechanical load as well as the analysis with a thermal load were carried out on this structure according to the Bersafe system. The thermal load consisted of a transient typical of an accident occurring in a sodium-cooled fast reactor, with a peak of the temperature (540 0 C) for the sodium inside the vessel with an insulating argon temperature constant at 525 0 C. The maximum value of the equivalent tension was found in the internal area at the union towards the vessel side. The analysis of the nozzle in 2-D consists in schematizing the structure as a cylinder-sphere intersection, where the sphere has a given relation to the

  17. Experimental aerodynamic and acoustic model testing of the Variable Cycle Engine (VCE) testbed coannular exhaust nozzle system: Comprehensive data report

    Science.gov (United States)

    Nelson, D. P.; Morris, P. M.

    1980-01-01

    The component detail design drawings of the one sixth scale model of the variable cycle engine testbed demonstrator exhaust syatem tested are presented. Also provided are the basic acoustic and aerodynamic data acquired during the experimental model tests. The model drawings, an index to the acoustic data, an index to the aerodynamic data, tabulated and graphical acoustic data, and the tabulated aerodynamic data and graphs are discussed.

  18. Effects of a Dual-Loop Exhaust Gas Recirculation System and Variable Nozzle Turbine Control on the Operating Parameters of an Automotive Diesel Engine

    Directory of Open Access Journals (Sweden)

    Giorgio Zamboni

    2017-01-01

    Full Text Available Reduction of NOX emissions and fuel consumption are the main topics in engine development, forcing the adoption of complex techniques and components, whose interactions have to be clearly understood for proper and reliable operations and management of the whole system. The investigation presented in this paper aimed at the development of integrated control strategies of turbocharging, high pressure (HP and low pressure (LP exhaust gas recirculation (EGR systems for better NOX emissions and fuel consumption, while analyzing their reciprocal influence and the resulting variations of engine quantities. The study was based on an extended experimental program in three part load engine operating conditions. In the paper a comparison of the behavior of the main engine sub-systems (intake and exhaust circuits, turbocharger turbine and compressor, HP and LP EGR loops in a wide range of operating modes is presented and discussed, considering open and closed loop approaches for variable nozzle turbine (VNT control, and showing how these affect engine performance and emissions. The potential of significant decrease in NOX emissions through the integration of HP and LP EGR was confirmed, while a proper VNT management allowed for improved fuel consumption level, if an open loop control scheme is followed. At higher engine speed and load, further actions have to be applied to compensate for observed soot emissions increase.

  19. Effect of nozzle and vertical-tail variables on the performance of a 3-surface F-15 model at transonic Mach numbers. [Langley 16 foot transonic tunnel

    Science.gov (United States)

    Pendergraft, O. C., Jr.; Bare, E. A.

    1982-01-01

    An investigation was conducted in the Langley 16 foot transonic tunnel to determine the longitudinal aerodynamic characteristics of twin two dimensional nozzles and twin baseline axisymmetric nozzles installed on a fully metric 0.047 scale model of the F-15 three surface configuration (canards, wing, horizontal tails). The effects on performance of two dimensional nozzle in flight thrust reversing, locations and orientation of the vertical tails, and deflections of the horizontal tails were also determined. Test data were obtained at static conditions and at Mach numbers from 0.60 to 1.20 over an angle of attack range from -2 deg to 15 deg. Nozzle pressure ratio was varied from jet off to about 6.5.

  20. Effect of Pressure on the Uniformity of Nozzles Transverse Distribution and Mathematical Model Development

    Directory of Open Access Journals (Sweden)

    Vladimir Višacki

    2017-01-01

    Full Text Available Timely and high-quality application of pesticides contributes to environmental protection, economical production and production of healthy food. The efficacy of pesticide application depends not only on the quality of pesticides but also the quality of the application. One of the factor that most influences the quality of applications, from the standpoint of mechanization, are nozzles. They working liquid applied on the surface the plant resulting in the same volume of pesticide is applied to the entire surface of the plants. To achieve this goal, nozzles must be performed uniform application of working liquid per unit area, or tractor sprayer working width. The variable factor in the application of pesticides may be nozzle and operating pressure. With increasing working pressure obtained smaller droplets. The paper presents test of three different nozzles. Each nozzle is characterized by a flat jet with an angle of 110° and a flow rate of 1.6 l∙min−1 at a pressure of 3 bar. Differ from each other are by the way of disintegration of the jet. Exactly this characteristic causes that with pressure change coming to changes in the uniformity of nozzles transverse distribution. So the best distribution has nozzle with a flat jet. The coefficient of variation is between roughly from 4 to 6 % at the pressure application of 2 to 4 bar. Obtained mathematical model that describes changes in the coefficient of variation depending on pressure applications can be a good basis for easy harmonization parameters in the pesticide application.

  1. Cold spray nozzle design

    Science.gov (United States)

    Haynes, Jeffrey D [Stuart, FL; Sanders, Stuart A [Palm Beach Gardens, FL

    2009-06-09

    A nozzle for use in a cold spray technique is described. The nozzle has a passageway for spraying a powder material, the passageway having a converging section and a diverging section, and at least the diverging section being formed from polybenzimidazole. In one embodiment of the nozzle, the converging section is also formed from polybenzimidazole.

  2. Focusing liquid microjets with nozzles

    International Nuclear Information System (INIS)

    Acero, A J; Ferrera, C; Montanero, J M; Gañán-Calvo, A M

    2012-01-01

    The stability of flow focusing taking place in a converging–diverging nozzle, as well as the size of the resulting microjets, is examined experimentally in this paper. The results obtained in most aspects of the problem are similar to those of the classical plate-orifice configuration. There is, however, a notable difference between flow focusing in nozzles and in the plate-orifice configuration. In the former case, the liquid meniscus oscillates laterally (global whipping) for a significant area of the control parameter plane, a phenomenon never observed when focusing with the plate-orifice configuration. Global whipping may constitute an important drawback of flow focusing with nozzles because it reduces the robustness of the technique. (paper)

  3. THE EFFECTS OF CLIMATIC VARIABLES AND CROP AREA ON MAIZE YIELD AND VARIABILITY IN GHANA

    Directory of Open Access Journals (Sweden)

    Henry De-Graft Acquah

    2012-10-01

    Full Text Available Climate change tends to have negative effects on crop yield through its influence on crop production. Understanding the relationship between climatic variables and crop area on the mean and variance of crop yield will facilitate development of appropriate policies to cope with climate change. This paper examines the effects of climatic variables and crop area on the mean and variance of maize yield in Ghana. The Just and Pope stochastic production function using the Cobb-Douglas functional form was employed. The results show that average maize yield is positively related to crop area and negatively related to rainfall and temperature. Furthermore, increase in crop area and temperature will enlarge maize yield variability while rainfall increase will decrease the variability in maize yield.

  4. Parametric Study of Sealant Nozzle

    Science.gov (United States)

    Yamamoto, Yoshimi

    It has become apparent in recent years the advancement of manufacturing processes in the aerospace industry. Sealant nozzles are a critical device in the use of fuel tank applications for optimal bonds and for ground service support and repair. Sealants has always been a challenging area for optimizing and understanding the flow patterns. A parametric study was conducted to better understand geometric effects of sealant flow and to determine whether the sealant rheology can be numerically modeled. The Star-CCM+ software was used to successfully develop the parametric model, material model, physics continua, and simulate the fluid flow for the sealant nozzle. The simulation results of Semco sealant nozzles showed the geometric effects of fluid flow patterns and the influences from conical area reduction, tip length, inlet diameter, and tip angle parameters. A smaller outlet diameter induced maximum outlet velocity at the exit, and contributed to a high pressure drop. The conical area reduction, tip angle and inlet diameter contributed most to viscosity variation phenomenon. Developing and simulating 2 different flow models (Segregated Flow and Viscous Flow) proved that both can be used to obtain comparable velocity and pressure drop results, however; differences are seen visually in the non-uniformity of the velocity and viscosity fields for the Viscous Flow Model (VFM). A comprehensive simulation setup for sealant nozzles was developed so other analysts can utilize the data.

  5. Experimental investigation and exergy analysis of the performance of a counter flow Ranque-Hilsch vortex tube with regard to nozzle cross-section areas

    Energy Technology Data Exchange (ETDEWEB)

    Dincer, K.; Avci, A.; Berber, A. [Dept. of Mechanical Eng., Fac. of Eng. and Architecture, Selcuk Univ., Selcuklu, Konya (Turkey); Baskaya, S. [Dept. of Mechanical Eng., Fac. of Eng. and Architecture, Gazi Univ., Maltepe, Ankara (Turkey)

    2010-08-15

    Exergy analysis and performance of a Ranque-Hilsch Vortex Tube (RHVT) with various nozzle cross-section areas (NCSA = 3 x 3, 4 x 4, 5 x 5 mm{sup 2}) were determined under inlet pressures (P{sub i}) of 260, 300 kPa (absolute) pressurized air. The maximum difference in the temperatures of hot output and cold output streams was obtained for NCSA = 3 x 3 mm{sup 2}. The total inlet exergy (sum E{sub i}), total outlet exergy (sum E{sub O}), total lost exergy (sum E{sub Lost}) and exergy efficiency ({eta}, %) were calculated. It was determined that the exergy efficiency of the system, varied between 1% and 39%, and the highest exergy efficiency was obtained for NCSA = 3 x 3 mm{sup 2}. The exergy efficiency strongly depends on the level of P{sub i}, {xi} and v{sub cold}. Variation of the exergy efficiency decreased with decreasing P{sub i}, {xi}, v{sub cold} and the highest and lowest exergy efficiencies were found when the values of P{sub i}, {xi}, v{sub cold} reached maximum and minimum levels, respectively. (author)

  6. Altitude Compensating Nozzle

    Science.gov (United States)

    Ruf, Joseph H.; Jones, Daniel

    2015-01-01

    The dual-bell nozzle (fig. 1) is an altitude-compensating nozzle that has an inner contour consisting of two overlapped bells. At low altitudes, the dual-bell nozzle operates in mode 1, only utilizing the smaller, first bell of the nozzle. In mode 1, the nozzle flow separates from the wall at the inflection point between the two bell contours. As the vehicle reaches higher altitudes, the dual-bell nozzle flow transitions to mode 2, to flow full into the second, larger bell. This dual-mode operation allows near optimal expansion at two altitudes, enabling a higher mission average specific impulse (Isp) relative to that of a conventional, single-bell nozzle. Dual-bell nozzles have been studied analytically and subscale nozzle tests have been completed.1 This higher mission averaged Isp can provide up to a 5% increase2 in payload to orbit for existing launch vehicles. The next important step for the dual-bell nozzle is to confirm its potential in a relevant flight environment. Toward this end, NASA Marshall Space Flight Center (MSFC) and Armstrong Flight Research Center (AFRC) have been working to develop a subscale, hot-fire, dual-bell nozzle test article for flight testing on AFRC's F15-D flight test bed (figs. 2 and 3). Flight test data demonstrating a dual-bell ability to control the mode transition and result in a sufficient increase in a rocket's mission averaged Isp should help convince the launch service providers that the dual-bell nozzle would provide a return on the required investment to bring a dual-bell into flight operation. The Game Changing Department provided 0.2 FTE to ER42 for this effort in 2014.

  7. Advanced exhaust nozzle technology

    Energy Technology Data Exchange (ETDEWEB)

    Glidewell, R J; Warburton, R E

    1981-01-01

    Recent developments in turbine engine exhaust nozzle technology include nonaxisymmetric nozzles, thrust reversing, and thrust vectoring. Trade studies have been performed to determine the impact of these developments on the thrust-to-weight ratio and specific fuel consumption of an advanced high performance, augmented turbofan engine. Results are presented in a manner which provides an understanding of the sources and magnitudes of differences in the basic elements of nozzle internal performance and weight as they relate to conventional, axisymmetric nozzle technology. Conclusions are presented and recommendations are made with regard to future directions of advanced development and demonstration. 5 refs.

  8. Firefighter Nozzle Reaction

    DEFF Research Database (Denmark)

    Chin, Selena K.; Sunderland, Peter B.; Jomaas, Grunde

    2017-01-01

    to anchor forces, the hose becomes straight. The nozzle reaction is found to equal the jet momentum flow rate, and it does not change when an elbow connects the hose to the nozzle. A forward force must be exerted by a firefighter or another anchor that matches the forward force that the jet would exert...... on a perpendicular wall. Three reaction expressions are derived, allowing it to be determined in terms of hose diameter, jet diameter, flow rate, and static pressure upstream of the nozzle. The nozzle reaction predictions used by the fire service are 56% to 90% of those obtained here for typical firefighting hand...

  9. External Cylindrical Nozzle with Controlled Vacuum

    Directory of Open Access Journals (Sweden)

    V. N. Pil'gunov

    2015-01-01

    Full Text Available There is a developed design of the external cylindrical nozzle with a vacuum camera. The paper studies the nozzle controllability of flow rate via regulated connection of the evacuated chamber to the atmosphere through an air throttle. Working capacity of the nozzle with inlet round or triangular orifice are researched. The gap is provided in the nozzle design between the external wall of the inlet orifice and the end face of the straight case in the nozzle case. The presented mathematical model of the nozzle with the evacuated chamber allows us to estimate the expected vacuum amount in the compressed section of a stream and maximum permissible absolute pressure at the inlet orifice. The paper gives experimental characteristics of the fluid flow process through the nozzle for different values of internal diameter of a straight case and an extent of its end face remoteness from an external wall of the inlet orifice. It estimates how geometry of nozzle constructive elements influences on the volume flow rate. It is established that the nozzle capacity significantly depends on the shape of inlet orifice. Triangular orifice nozzles steadily work in the mode of completely filled flow area of the straight case at much more amounts of the limit pressure of the flow. Vacuum depth in the evacuated chamber also depends on the shape of inlet orifice: the greatest vacuum is reached in a nozzle with the triangular orifice which 1.5 times exceeds the greatest vacuum with the round orifice. Possibility to control nozzle capacity through the regulated connection of the evacuated chamber to the atmosphere was experimentally estimated, thus depth of flow rate regulation of the nozzle with a triangular orifice was 45% in comparison with 10% regulation depth of the nozzle with a round orifice. Depth of regulation calculated by a mathematical model appeared to be much more. The paper presents experimental dependences of the flow coefficients of nozzle input orifice

  10. Firefighter Nozzle Reaction

    DEFF Research Database (Denmark)

    Chin, Selena K.; Sunderland, Peter B.; Jomaas, Grunde

    2017-01-01

    Nozzle reaction and hose tension are analyzed using conservation of fluid momentum and assuming steady, inviscid flow and a flexible hose in frictionless contact with the ground. An expression that is independent of the bend angle is derived for the hose tension. If this tension is exceeded owing...... to anchor forces, the hose becomes straight. The nozzle reaction is found to equal the jet momentum flow rate, and it does not change when an elbow connects the hose to the nozzle. A forward force must be exerted by a firefighter or another anchor that matches the forward force that the jet would exert...... on a perpendicular wall. Three reaction expressions are derived, allowing it to be determined in terms of hose diameter, jet diameter, flow rate, and static pressure upstream of the nozzle. The nozzle reaction predictions used by the fire service are 56% to 90% of those obtained here for typical firefighting hand...

  11. Design and Analyses of High Aspect Ratio Nozzles for Distributed Propulsion Acoustic Measurements

    Science.gov (United States)

    Dippold, Vance F., III

    2016-01-01

    A series of three convergent round-to-rectangular high-aspect ratio nozzles were designed for acoustics measurements. The nozzles have exit area aspect ratios of 8:1, 12:1, and 16:1. With septa inserts, these nozzles will mimic an array of distributed propulsion system nozzles, as found on hybrid wing-body aircraft concepts. Analyses were performed for the three nozzle designs and showed that the flow through the nozzles was free of separated flow and shocks. The exit flow was mostly uniform with the exception of a pair of vortices at each span-wise end of the nozzle.

  12. Geochemical Modeling Of F Area Seepage Basin Composition And Variability

    International Nuclear Information System (INIS)

    Millings, M.; Denham, M.; Looney, B.

    2012-01-01

    From the 1950s through 1989, the F Area Seepage Basins at the Savannah River Site (SRS) received low level radioactive wastes resulting from processing nuclear materials. Discharges of process wastes to the F Area Seepage Basins followed by subsequent mixing processes within the basins and eventual infiltration into the subsurface resulted in contamination of the underlying vadose zone and downgradient groundwater. For simulating contaminant behavior and subsurface transport, a quantitative understanding of the interrelated discharge-mixing-infiltration system along with the resulting chemistry of fluids entering the subsurface is needed. An example of this need emerged as the F Area Seepage Basins was selected as a key case study demonstration site for the Advanced Simulation Capability for Environmental Management (ASCEM) Program. This modeling evaluation explored the importance of the wide variability in bulk wastewater chemistry as it propagated through the basins. The results are intended to generally improve and refine the conceptualization of infiltration of chemical wastes from seepage basins receiving variable waste streams and to specifically support the ASCEM case study model for the F Area Seepage Basins. Specific goals of this work included: (1) develop a technically-based 'charge-balanced' nominal source term chemistry for water infiltrating into the subsurface during basin operations, (2) estimate the nature of short term and long term variability in infiltrating water to support scenario development for uncertainty quantification (i.e., UQ analysis), (3) identify key geochemical factors that control overall basin water chemistry and the projected variability/stability, and (4) link wastewater chemistry to the subsurface based on monitoring well data. Results from this study provide data and understanding that can be used in further modeling efforts of the F Area groundwater plume. As identified in this study, key geochemical factors affecting basin

  13. Sensitivity of marine protected area network connectivity to atmospheric variability.

    Science.gov (United States)

    Fox, Alan D; Henry, Lea-Anne; Corne, David W; Roberts, J Murray

    2016-11-01

    International efforts are underway to establish well-connected systems of marine protected areas (MPAs) covering at least 10% of the ocean by 2020. But the nature and dynamics of ocean ecosystem connectivity are poorly understood, with unresolved effects of climate variability. We used 40-year runs of a particle tracking model to examine the sensitivity of an MPA network for habitat-forming cold-water corals in the northeast Atlantic to changes in larval dispersal driven by atmospheric cycles and larval behaviour. Trajectories of Lophelia pertusa larvae were strongly correlated to the North Atlantic Oscillation (NAO), the dominant pattern of interannual atmospheric circulation variability over the northeast Atlantic. Variability in trajectories significantly altered network connectivity and source-sink dynamics, with positive phase NAO conditions producing a well-connected but asymmetrical network connected from west to east. Negative phase NAO produced reduced connectivity, but notably some larvae tracked westward-flowing currents towards coral populations on the mid-Atlantic ridge. Graph theoretical metrics demonstrate critical roles played by seamounts and offshore banks in larval supply and maintaining connectivity across the network. Larval longevity and behaviour mediated dispersal and connectivity, with shorter lived and passive larvae associated with reduced connectivity. We conclude that the existing MPA network is vulnerable to atmospheric-driven changes in ocean circulation.

  14. Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

    Energy Technology Data Exchange (ETDEWEB)

    Bouriaud, O. [Inst. National de la Recherche Agronomique, Centre de Recherches Forestieres de Nancy, Champenoux (France); Soudani, K. [Univ. Paris-Sud XI, Dept. d' Ecophysiologie Vegetale, Lab. Ecologie Systematique et Evolution, Orsay Cedex (France); Breda, N. [Inst. National de la Recherche Agronomique, Centre de Recherches Forestieres de Nancy, Champenoux (France)

    2003-06-01

    Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m{sup 2}{center_dot}g{sup -1}) is used to convert dry leaf litter biomass (g .m{sup -}2) into leaf area per ground unit area (m{sup 2}{center_dot}m{sup -2}). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m{sup 2}) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm{sup 2}{center_dot}g{sup -1}. Nevertheless, no relationship was found between SLA and stand canopy closure or PAI On the contrary, a significant

  15. Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

    International Nuclear Information System (INIS)

    Bouriaud, O.; Soudani, K.; Breda, N.

    2003-01-01

    Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m 2 ·g -1 ) is used to convert dry leaf litter biomass (g .m - 2) into leaf area per ground unit area (m 2 ·m -2 ). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m 2 ) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm 2 ·g -1 . Nevertheless, no relationship was found between SLA and stand canopy closure or PAI On the contrary, a significant relationship between SLA and soil properties was observed. Both SLA

  16. Consistency of variables in PCS and JASTRO great area database

    International Nuclear Information System (INIS)

    Nishino, Tomohiro; Teshima, Teruki; Abe, Mitsuyuki

    1998-01-01

    To examine whether the Patterns of Care Study (PCS) reflects the data for the major areas in Japan, the consistency of variables in the PCS and in the major area database of the Japanese Society for Therapeutic Radiology and Oncology (JASTRO) were compared. Patients with esophageal or uterine cervical cancer were sampled from the PCS and JASTRO databases. From the JASTRO database, 147 patients with esophageal cancer and 95 patients with uterine cervical cancer were selected according to the eligibility criteria for the PCS. From the PCS, 455 esophageal and 432 uterine cervical cancer patients were surveyed. Six items for esophageal cancer and five items for uterine cervical cancer were selected for a comparative analysis of PCS and JASTRO databases. Esophageal cancer: Age (p=.0777), combination of radiation and surgery (p=.2136), and energy of the external beam (p=.6400) were consistent for PCS and JASTRO. However, the dose of the external beam for the non-surgery group showed inconsistency (p=.0467). Uterine cervical cancer: Age (p=.6301) and clinical stage (p=.8555) were consistent for the two sets of data. However, the energy of the external beam (p<.0001), dose rate of brachytherapy (p<.0001), and brachytherapy utilization by clinical stage (p<.0001) showed inconsistencies. It appears possible that the JASTRO major area database could not account for all patients' backgrounds and factors and that both surveys might have an imbalance in the stratification of institutions including differences in equipment and staffing patterns. (author)

  17. Cold water injection nozzles

    International Nuclear Information System (INIS)

    Kura, Masaaki; Maeda, Masamitsu; Endo, Takio.

    1979-01-01

    Purpose: To inject cold water in a reactor without applying heat cycles to a reactor container and to the inner wall of a feedwater nozzle by securing a perforated plate at the outlet of the cold water injection nozzle. Constitution: A disc-like cap is secured to the final end of a return nozzle of a control rod drive. The cap prevents the flow of a high temperature water flowing downward in the reactor from entering into the nozzle. The cap is perforated with a plurality of bore holes for injecting cold water into the reactor. The cap is made to about 100 mm in thickness so that the cold water passing through the bore holes is heated by the heat conduction in the cap. Accordingly, the flow of high temperature water flowing downwardly in the reactor is inhibited by the cap from backward flowing into the nozzle. Moreover, the flow of the cold water in the nozzle is controlled and rectified when passed through the bore holes in the cap and then injected into the reactor. (Yoshino, Y.)

  18. Characterisation of subsonic axisymmetric nozzles

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav

    2008-01-01

    Roč. 86, č. 11 (2008), s. 1253-1262 ISSN 0263-8762 R&D Projects: GA AV ČR IAA200760705 Institutional research plan: CEZ:AV0Z20760514 Keywords : nozzle * characterisation * nozzle properties * nozzle invariants Subject RIV: BK - Fluid Dynamics Impact factor: 0.989, year: 2008

  19. Improving risk estimates of runoff producing areas: formulating variable source areas as a bivariate process.

    Science.gov (United States)

    Cheng, Xiaoya; Shaw, Stephen B; Marjerison, Rebecca D; Yearick, Christopher D; DeGloria, Stephen D; Walter, M Todd

    2014-05-01

    Predicting runoff producing areas and their corresponding risks of generating storm runoff is important for developing watershed management strategies to mitigate non-point source pollution. However, few methods for making these predictions have been proposed, especially operational approaches that would be useful in areas where variable source area (VSA) hydrology dominates storm runoff. The objective of this study is to develop a simple approach to estimate spatially-distributed risks of runoff production. By considering the development of overland flow as a bivariate process, we incorporated both rainfall and antecedent soil moisture conditions into a method for predicting VSAs based on the Natural Resource Conservation Service-Curve Number equation. We used base-flow immediately preceding storm events as an index of antecedent soil wetness status. Using nine sub-basins of the Upper Susquehanna River Basin, we demonstrated that our estimated runoff volumes and extent of VSAs agreed with observations. We further demonstrated a method for mapping these areas in a Geographic Information System using a Soil Topographic Index. The proposed methodology provides a new tool for watershed planners for quantifying runoff risks across watersheds, which can be used to target water quality protection strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Duplex tab exhaust nozzle

    Science.gov (United States)

    Gutmark, Ephraim Jeff (Inventor); Martens, Steven (nmn) (Inventor)

    2012-01-01

    An exhaust nozzle includes a conical duct terminating in an annular outlet. A row of vortex generating duplex tabs are mounted in the outlet. The tabs have compound radial and circumferential aft inclination inside the outlet for generating streamwise vortices for attenuating exhaust noise while reducing performance loss.

  1. Isentropic Gas Flow for the Compressible Euler Equation in a Nozzle

    Science.gov (United States)

    Tsuge, Naoki

    2013-08-01

    We study the motion of isentropic gas in a nozzle. Nozzles are used to increase the thrust of engines or to accelerate a flow from subsonic to supersonic. Nozzles are essential parts for jet engines, rocket engines and supersonicwind tunnels. In the present paper, we consider unsteady flow, which is governed by the compressible Euler equation, and prove the existence of global solutions for the Cauchy problem. For this problem, the existence theorem has already been obtained for initial data away from the sonic state, (Liu in Commun Math Phys 68:141-172, 1979). Here, we are interested in the transonic flow, which is essential for engineering and physics. Although the transonic flow has recently been studied (Tsuge in J Math Kyoto Univ 46:457-524, 2006; Lu in Nonlinear Anal Real World Appl 12:2802-2810, 2011), these papers assume monotonicity of the cross section area. Here, we consider the transonic flow in a nozzle with a general cross section area. When we prove global existence, the most difficult point is obtaining a bounded estimate for approximate solutions. To overcome this, we employ a new invariant region that depends on the space variable. Moreover, we introduce a modified Godunov scheme. The corresponding approximate solutions consist of piecewise steady-state solutions of an auxiliary equation, which yield a desired bounded estimate. In order to prove their convergence, we use the compensated compactness framework.

  2. New atomization nozzle for spray drying

    NARCIS (Netherlands)

    Deventer, H.C. van; Houben, R.J.; Koldeweij, R.B.J.

    2013-01-01

    A new atomization nozzle based on ink jet technology is introduced for spray drying. Application areas are the food and dairy industry, in the first instance, because in these industries the quality demands on the final powders are high with respect to heat load, powder shape, and size distribution.

  3. Rainfall trends and variability in selected areas of Ethiopian Somali ...

    African Journals Online (AJOL)

    Moreover, proper spatial distribution of meteorological stations together with early warning system are required to further support local adaptive and coping strategies that the community designed towards rainfall variability in particular and climate change/disaster and risk at large. Keywords: Ethiopian Somali Region, Gode, ...

  4. Plant community variability on a small area in southeastern Montana

    Science.gov (United States)

    James G. MacCracken; Daniel W. Uresk; Richard M. Hansen

    1984-01-01

    Plant communities are inherently variable due to a number of environmental and biological forces. Canopy cover and aboveground biomass were determined for understory vegetation in plant communities of a prairie grassland-forest ecotone in southeastern Montana. Vegetation units were described using polar ordination and stepwise discriminant analysis. Nine of a total of...

  5. Stereophysicochemical variability plots highlight conserved antigenic areas in Flaviviruses

    Directory of Open Access Journals (Sweden)

    Zhou Bin

    2005-04-01

    Full Text Available Abstract Background Flaviviruses, which include Dengue (DV and West Nile (WN, mutate in response to immune system pressure. Identifying escape mutants, variant progeny that replicate in the presence of neutralizing antibodies, is a common way to identify functionally important residues of viral proteins. However, the mutations typically occur at variable positions on the viral surface that are not essential for viral replication. Methods are needed to determine the true targets of the neutralizing antibodies. Results Stereophysicochemical variability plots (SVPs, 3-D images of protein structures colored according to variability, as determined by our PCPMer program, were used to visualize residues conserved in their physical chemical properties (PCPs near escape mutant positions. The analysis showed 1 that escape mutations in the flavivirus envelope protein are variable residues by our criteria and 2 two escape mutants found at the same position in many flaviviruses sit above clusters of conserved residues from different regions of the linear sequence. Conservation patterns in T-cell epitopes in the NS3- protease suggest a similar mechanism of immune system evasion. Conclusion The SVPs add another dimension to structurally defining the binding sites of neutralizing antibodies. They provide a useful aid for determining antigenically important regions and designing vaccines.

  6. Premixed direct injection nozzle

    Science.gov (United States)

    Zuo, Baifang [Simpsonville, SC; Johnson, Thomas Edward [Greer, SC; Lacy, Benjamin Paul [Greer, SC; Ziminsky, Willy Steve [Simpsonville, SC

    2011-02-15

    An injection nozzle having a main body portion with an outer peripheral wall is disclosed. The nozzle includes a plurality of fuel/air mixing tubes disposed within the main body portion and a fuel flow passage fluidly connected to the plurality of fuel/air mixing tubes. Fuel and air are partially premixed inside the plurality of the tubes. A second body portion, having an outer peripheral wall extending between a first end and an opposite second end, is connected to the main body portion. The partially premixed fuel and air mixture from the first body portion gets further mixed inside the second body portion. The second body portion converges from the first end toward said second end. The second body portion also includes cooling passages that extend along all the walls around the second body to provide thermal damage resistance for occasional flame flash back into the second body.

  7. Limit loads in nozzles

    International Nuclear Information System (INIS)

    Zouain, N.

    1983-01-01

    The static method for the evaluation of the limit loads of a perfectly elasto-plastic structure is presented. Using the static theorem of Limit Analysis and the Finite Element Method, a lower bound for the colapso load can be obtained through a linear programming problem. This formulation if then applied to symmetrically loaded shells of revolution and some numerical results of limit loads in nozzles are also presented. (Author) [pt

  8. Distribuição da calda herbicida por pontas de pulverização agrícola utilizadas em áreas de reflorestamento com eucalipto Herbicide distribution by spraying nozzles used in eucalyptus reforestation areas

    Directory of Open Access Journals (Sweden)

    Marcelo da C. Ferreira

    2009-06-01

    Full Text Available O trabalho teve como objetivo avaliar a distribuição de calda por pontas de pulverização hidráulicas para a aplicação de herbicidas em pré-emergência das plantas daninhas, em função do espaçamento na barra utilizada em áreas de reflorestamento com eucalipto. O experimento foi realizado no Laboratório de Ciência das Plantas Daninhas do Departamento de Fitossanidade da UNESP, Câmpus de Jaboticabal. Foram utilizados os modelos com indução de ar AIUB 025, AI 110025, TTI 110015 e DB 12002, considerando o espaçamento de 0,8; 1,0; 1,2 e 1,5 m entre eles. A avaliação da distribuição da calda pulverizada foi realizada em mesa de deposição. Pulverizou-se água com 0,1% do adjuvante não iônico alquilfenol. Os valores observados foram utilizados para a obtenção das curvas de deposição e do coeficiente de variação. Para a sobreposição de dois exemplares de pontas, conclui-se que o modelo AIUB 025 possui menores coeficientes de variação, resultando em melhores características operacionais em relação à AI 110025, TTI 110015 e DB 12002. Para a utilização de três exemplares de pontas, seguindo somente o critério da distribuição da calda, a melhor combinação foi entre AIUB 025 e DB 12002, como intercalar. A utilização da ponta intercalar aumentou significativamente o consumo de calda.This work aimed to evaluate spray distribution by spraying hydraulic nozzles for the application of herbicides in the pre-emergence of weeds, due to the spacing in spraying boom used in areas reforested with eucalyptus. The trial was carried out at the Weed Science Laboratory from the Phytosanitary Department, UNESP - Jaboticabal Campus - SP, Brazil. It was used air induction nozzles AIUB 025, AI 110025, TTI 110015 and DB 12002, on spacing 0.8; 1.0; 1.2; and 1.5 m, between them. The spraying liquid distribution evaluation was done in patternator table. It was sprayed water plus 0.1% of non-ionic adjuvant alkylphenol . The observed

  9. Stress analyses of flat plates with attached nozzles. Vol. 2: Experimental stress analyses of a flat plate with one nozzle attached

    International Nuclear Information System (INIS)

    Battiste, R.L.; Peters, W.H.; Ranson, W.F.; Swinson, W.F.

    1975-07-01

    Vol. 1 of this report compares experimental results with theoretical stress distributions for a flat plate with one nozzle configuration and for a flat plate with two closely spaced nozzles attached. This volume contains the complete test results for a flat plate with one nozzle attached that was subjected to 1:1 and 1:2 biaxial planar loadings on the plate, to a thrust loading on the nozzle, and to a moment loading on the nozzle. The plate tested was 36 x 36 x 0.375 in., and the attached nozzle had an outer dia of 2.625 in. and a 0.250-in.-thick wall. The nozzle was located in the center of the plate and was considered to be free of weld distortions and irregularities in the junction area. (U.S.)

  10. Nozzle design study for a quasi-axisymmetric scramjet-powered vehicle at Mach 7.9 flight conditions

    Science.gov (United States)

    Tanimizu, Katsuyoshi; Mee, David J.; Stalker, Raymond J.; Jacobs, Peter A.

    2013-09-01

    A nozzle shape optimization study for a quasi-axisymmetric scramjet has been performed for a Mach 7.9 operating condition with hydrogen fuel, aiming at the application of a hypersonic airbreathing vehicle. In this study, the nozzle geometry which is parameterized by a set of design variables, is optimized for the single objective of maximum net thrust using an in-house CFD solver for inviscid flowfields with a simple force prediction methodology. The combustion is modelled using a simple chemical reaction code. The effects of the nozzle design on the overall vehicle performance are discussed. For the present geometry, net thrust is achieved for the optimized vehicle design. The results of the nozzle-optimization study show that performance is limited by the nozzle area ratio that can be incorporated into the vehicle without leading to too large a base diameter of the vehicle and increasing the external drag of the vehicle. This study indicates that it is very difficult to achieve positive thrust at Mach 7.9 using the basic geometry investigated.

  11. Variable area manifolds for ring mirror heat exchangers

    Science.gov (United States)

    Eng, Albert; Senterfitt, Donald R.

    1988-05-01

    A laser ring mirror assembly is disclosed which supports and cools an annular ring mirror of a high powered laser with a cooling manifold which has a coolant flow design which is intended to reduce thermal distortions of the ring mirror by minimizing azimuthal variations in temperature around its circumference. The cooling manifold has complementary pairs of cooling passages each of which conduct coolant in opposite flow directions. The manifold also houses adjusters which vary the depth between the annular ring mirror and each cooling, and which vary the flow area of the cooling passage to produce a control over the cooling characteristics of the cooling manifold.

  12. A Parametric Investigation of Nozzle Planform and Internal/External Geometry at Transonic Speeds

    Science.gov (United States)

    Cler, Daniel L.

    1995-01-01

    An experimental investigation of multidisciplinary (scarfed trailing edge) nozzle divergent flap geometry was conducted at transonic speeds in the NASA Langley 16-Foot Transonic Tunnel. The geometric parameters investigated include nozzle planform, nozzle contouring location (internal and/or external), and nozzle area ratio (area ratio 1.2 and 2.0). Data were acquired over a range of Mach Numbers from 0.6 to 1.2, angle-of-attack from 0.0 degrees to 9.6 degrees and nozzle pressure ratios from 1.0 to 20.0. Results showed that increasing the rate of change internal divergence angle across the width of the nozzle or increasing internal contouring will decrease static, aeropropulsive and thrust removed drag performance regardless of the speed regime. Also, increasing the rate of change in boattail angle across the width of the nozzle or increasing external contouring will provide the lowest thrust removed drag. Scarfing of the nozzle trailing edges reduces the aeropropulsive performance for the most part and adversely affects the nozzle plume shape at higher nozzle pressure ratios thus increasing the thrust removed drag. The effects of contouring were primary in nature and the effects of planform were secondary in nature. Larger losses occur supersonically than subsonically when scarfing of nozzle trailing edges occurs. The single sawtooth nozzle almost always provided lower thrust removed drag than the double sawtooth nozzles regardless the speed regime. If internal contouring is required, the double sawtooth nozzle planform provides better static and aeropropulsive performance than the single sawtooth nozzle and if no internal contouring is required the single sawtooth provides the highest static and aeropropulsive performance.

  13. Prototype particulate stack sampler with single-cut nozzle and microcomputer calculating/display system

    International Nuclear Information System (INIS)

    Eler, J.C.; Littlefield, L.G.; Tillery, M.I.

    1979-01-01

    A prototype particulate stack sampler (PPSS) has been developed to improve on the existing EPA Method 5 sampling apparatus. Its primary features are (1) higher sampling rate (56 1/min); (2) display (on demand) of all required variables and calculated values by a microcomputer-based calculating and display system; (3) continuous stack gas moisture determination; (4) a virtual impactor nozzle with 3 μm mass median diameter cutpoint which collects fine and coarse particle fractions on separate glass fiber filters; (5) a variable-area inlet to maintain isokinetic sampling conditions; and (6) conversion to stainless steel components from the glass specified by EPA Method 5. The basic sampling techniques of EPA Method 5 have been retained; however, versatility in the form of optional in-stack filters and general modernization of the stack sampler have been provided in the prototype design. Laboratory testing with monodisperse dye aerosols has shown the present variable inlet, virtual impactor nozzle to have a collection efficiency which is less than 77% and significant wall losses. This is primarily due to lack of symmetry in this rectangular jet impactor and short transition lengths dictated by physical design constraints (required passage of the nozzle through a 7.6 cm (3 in) diameter stack port). Electronic components have shown acceptable service in laboratory testing although no field testing of the prototype under a broad range of temperature, humidity, and SO 2 concentration has been undertaken

  14. Computational study of variable area ejector rocket flowfields

    Science.gov (United States)

    Etele, Jason

    Access to space has always been a scientific priority for countries which can afford the prohibitive costs associated with launch. However, the large scale exploitation of space by the business community will require the cost of placing payloads into orbit be dramatically reduced for space to become a truly profitable commodity. To this end, this work focuses on a next generation propulsive technology called the Rocket Based Combined Cycle (RBCC) engine in which rocket, ejector, ramjet, and scramjet cycles operate within the same engine environment. Using an in house numerical code solving the axisymmetric version of the Favre averaged Navier Stokes equations (including the Wilcox ko turbulence model with dilatational dissipation) a systematic study of various ejector designs within an RBCC engine is undertaken. It is shown that by using a central rocket placed along the axisymmetric axis in combination with an annular rocket placed along the outer wall of the ejector, one can obtain compression ratios of approximately 2.5 for the case where both the entrained air and rocket exhaust mass flows are equal. Further, it is shown that constricting the exit area, and the manner in which this constriction is performed, has a significant positive impact on the compression ratio. For a decrease in area of 25% a purely conical ejector can increase the compression ratio by an additional 23% compared to an equal length unconstricted ejector. The use of a more sharply angled conical section followed by a cylindrical section to maintain equivalent ejector lengths can further increase the compression ratio by 5--7% for a total increase of approximately 30%.

  15. Outlining precision boundaries among areas with different variability standards using magnetic susceptibility and geomorphic surfaces

    OpenAIRE

    Matias,Sammy S. R.; Marques Júnior,José; Siqueira,Diego S.; Pereira,Gener T.

    2014-01-01

    There is an increasing demand for detailed maps that represent in a simplified way the knowledge of the variability of a particular area or region maps. The objective was to outline precision boundaries among areas with different accuracy variability standards using magnetic susceptibility and geomorphic surfaces. The study was conducted in an area of 110 ha, which identified three compartment landscapes based on the geomorphic surfaces model. To determinate pH, organic matter, phosphorus, po...

  16. Application of LBB to a nozzle-pipe interface

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Y.J.; Sohn, G.H.; Kim, Y.J. [and others

    1997-04-01

    Typical LBB (Leak-Before-Break) analysis is performed for the highest stress location for each different type of material in the high energy pipe line. In most cases, the highest stress occurs at the nozzle and pipe interface location at the terminal end. The standard finite element analysis approach to calculate J-Integral values at the crack tip utilizes symmetry conditions when modeling near the nozzle as well as away from the nozzle region to minimize the model size and simplify the calculation of J-integral values at the crack tip. A factor of two is typically applied to the J-integral value to account for symmetric conditions. This simplified analysis can lead to conservative results especially for small diameter pipes where the asymmetry of the nozzle-pipe interface is ignored. The stiffness of the residual piping system and non-symmetries of geometry along with different material for the nozzle, safe end and pipe are usually omitted in current LBB methodology. In this paper, the effects of non-symmetries due to geometry and material at the pipe-nozzle interface are presented. Various LBB analyses are performed for a small diameter piping system to evaluate the effect a nozzle has on the J-integral calculation, crack opening area and crack stability. In addition, material differences between the nozzle and pipe are evaluated. Comparison is made between a pipe model and a nozzle-pipe interface model, and a LBB PED (Piping Evaluation Diagram) curve is developed to summarize the results for use by piping designers.

  17. The effects of a spray slurry nozzle on copper CMP for reduction in slurry consumption

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Da Sol; Jeong, Hae Do [Pusan National University, Busan (Korea, Republic of); Lee, Hyun Seop [Tongmyong University, Busan (Korea, Republic of)

    2015-12-15

    The environmental impact of semiconductor manufacturing has been a big social problem, like greenhouse gas emission. Chemical mechanical planarization (CMP), a wet process which consumes chemical slurries, seriously impacts environmental sustain ability and cost-effectiveness. This paper demonstrates the superiority of a full-cone spray slurry nozzle to the conventional tube-type slurry nozzle in Cu CMP. It was observed that the spray nozzle made a weak slurry wave at the retaining ring unlike a conventional nozzle, because the slurry was supplied uniformly in broader areas. Experiments were implemented with different slurry flow rates and spray nozzle heights. Spray nozzle performance is controlled by the spray angle and spray height. The process temperature was obtained with an infrared (IR) sensor and an IR thermal imaging camera to investigate the cooling effect of the spray. The results show that the spray nozzle provides a higher Material removal rate (MRR), lower non-uniformity (NU), and lower temperature than the conventional nozzle. Computational fluid dynamics techniques show that the turbulence kinetic energy and slurry velocity of the spray nozzle are much higher than those of the conventional nozzle. Finally, it can be summarized that the spray nozzle plays a significant role in slurry efficiency by theory of Minimum quantity lubrication (MQL).

  18. Evaluation of the effects of break nozzle configuration in the Semiscale Mod-1 system

    International Nuclear Information System (INIS)

    Hanson, R.G.

    1977-08-01

    The Semiscale Mod-1 Program has utilized two different break nozzle configurations in the test system. An evaluation has been made to determine the effect these break nozzle configurations have on system thermal-hydraulic response during a 200 percent double-ended cold leg break loss-of-coolant accident simulation. The first nozzle was a convergent-divergent nozzle (Henry nozzle) and the second, an elongated constant area throat nozzle. Analysis is confined primarily to system response phenomena observed to be affected by the nozzle configuration and concentrates on the fluid response at the break and the resulting core behavior during subcooled and saturated blowdown. The evaluation shows that considerable difference in system response occurs as a result of the difference in break nozzle configuration. The elongated throat nozzle was scaled from the Loss-of-Fluid Test (LOFT) nozzle geometry and since the LOFT counterpart tests were designed to provide results for the LOFT Program, the elongated throat nozzle was used in the subsequent LOFT counterpart tests

  19. The effects of a spray slurry nozzle on copper CMP for reduction in slurry consumption

    International Nuclear Information System (INIS)

    Lee, Da Sol; Jeong, Hae Do; Lee, Hyun Seop

    2015-01-01

    The environmental impact of semiconductor manufacturing has been a big social problem, like greenhouse gas emission. Chemical mechanical planarization (CMP), a wet process which consumes chemical slurries, seriously impacts environmental sustain ability and cost-effectiveness. This paper demonstrates the superiority of a full-cone spray slurry nozzle to the conventional tube-type slurry nozzle in Cu CMP. It was observed that the spray nozzle made a weak slurry wave at the retaining ring unlike a conventional nozzle, because the slurry was supplied uniformly in broader areas. Experiments were implemented with different slurry flow rates and spray nozzle heights. Spray nozzle performance is controlled by the spray angle and spray height. The process temperature was obtained with an infrared (IR) sensor and an IR thermal imaging camera to investigate the cooling effect of the spray. The results show that the spray nozzle provides a higher Material removal rate (MRR), lower non-uniformity (NU), and lower temperature than the conventional nozzle. Computational fluid dynamics techniques show that the turbulence kinetic energy and slurry velocity of the spray nozzle are much higher than those of the conventional nozzle. Finally, it can be summarized that the spray nozzle plays a significant role in slurry efficiency by theory of Minimum quantity lubrication (MQL).

  20. Understanding Hydrological Processes in Variable Source Areas in the Glaciated Northeastern US Watersheds under Variable Climate Conditions

    Science.gov (United States)

    Steenhuis, T. S.; Azzaino, Z.; Hoang, L.; Pacenka, S.; Worqlul, A. W.; Mukundan, R.; Stoof, C.; Owens, E. M.; Richards, B. K.

    2017-12-01

    The New York City source watersheds in the Catskill Mountains' humid, temperate climate has long-term hydrological and water quality monitoring data It is one of the few catchments where implementation of source and landscape management practices has led to decreased phosphorus concentration in the receiving surface waters. One of the reasons is that landscape measures correctly targeted the saturated variable source runoff areas (VSA) in the valley bottoms as the location where most of the runoff and other nonpoint pollutants originated. Measures targeting these areas were instrumental in lowering phosphorus concentration. Further improvements in water quality can be made based on a better understanding of the flow processes and water table fluctuations in the VSA. For that reason, we instrumented a self-contained upland variable source watershed with a landscape characteristic of a soil underlain by glacial till at shallow depth similar to the Catskill watersheds. In this presentation, we will discuss our experimental findings and present a mathematical model. Variable source areas have a small slope making gravity the driving force for the flow, greatly simplifying the simulation of the flow processes. The experimental data and the model simulations agreed for both outflow and water table fluctuations. We found that while the flows to the outlet were similar throughout the year, the discharge of the VSA varies greatly. This was due to transpiration by the plants which became active when soil temperatures were above 10oC. We found that shortly after the temperature increased above 10oC the baseflow stopped and only surface runoff occurred when rainstorms exceeded the storage capacity of the soil in at least a portion of the variable source area. Since plant growth in the variable source area was a major variable determining the base flow behavior, changes in temperature in the future - affecting the duration of the growing season - will affect baseflow and

  1. Using small area estimation and Lidar-derived variables for multivariate prediction of forest attributes

    Science.gov (United States)

    F. Mauro; Vicente Monleon; H. Temesgen

    2015-01-01

    Small area estimation (SAE) techniques have been successfully applied in forest inventories to provide reliable estimates for domains where the sample size is small (i.e. small areas). Previous studies have explored the use of either Area Level or Unit Level Empirical Best Linear Unbiased Predictors (EBLUPs) in a univariate framework, modeling each variable of interest...

  2. Characteristics of Multiplexed Grooved Nozzles for High Flow Rate Electrospray

    International Nuclear Information System (INIS)

    Kim, Kyoung Tae; Kim, Woo Jin; Kim, Sang Soo

    2007-01-01

    The electrospray operated in the cone-jet mode can generate highly charged micro droplets in an almost uniform size at flow rates. Therefore, the multiplexing system which can retain the characteristics of the cone-jet mode is inevitable for the electrospray application. This experiment reports the multiplexed grooved nozzle system with the extractor. The effects of the grooves and the extractor on the performance of the electrospray were evaluated through experiments. Using the grooved nozzle, the stable cone-jet mode can be achieved at the each groove in the grooved mode. Furthermore, the number of nozzles per unit area is increased by the extractor. The multiplexing density is 12 jets per cm 2 at 30 mm distance from the nozzle tip to the ground plate. The multiplexing system for the high flow rate electrospray is realized with the extractor which can diminish the space charge effect without sacrificing characteristics of the cone-jet mode

  3. Injection nozzle for a turbomachine

    Science.gov (United States)

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo

    2012-09-11

    A turbomachine includes a compressor, a combustor operatively connected to the compressor, an end cover mounted to the combustor, and an injection nozzle assembly operatively connected to the combustor. The injection nozzle assembly includes a first end portion that extends to a second end portion, and a plurality of tube elements provided at the second end portion. Each of the plurality of tube elements defining a fluid passage includes a body having a first end section that extends to a second end section. The second end section projects beyond the second end portion of the injection nozzle assembly.

  4. Airfoil nozzle and shroud assembly

    Science.gov (United States)

    Shaffer, J.E.; Norton, P.F.

    1997-06-03

    An airfoil and nozzle assembly are disclosed including an outer shroud having a plurality of vane members attached to an inner surface and having a cantilevered end. The assembly further includes a inner shroud being formed by a plurality of segments. Each of the segments having a first end and a second end and having a recess positioned in each of the ends. The cantilevered end of the vane member being positioned in the recess. The airfoil and nozzle assembly being made from a material having a lower rate of thermal expansion than that of the components to which the airfoil and nozzle assembly is attached. 5 figs.

  5. Flow-throttling orifice nozzle

    International Nuclear Information System (INIS)

    Sletten, H.L.

    1975-01-01

    A series-parallel-flow type throttling apparatus to restrict coolant flow to certain fuel assemblies of a nuclear reactor is comprised of an axial extension nozzle of the fuel assembly. The nozzle has a series of concentric tubes with parallel-flow orifice holes in each tube. Flow passes from a high pressure plenum chamber outside the nozzle through the holes in each tube in series to the inside of the innermost tube where the coolant, having dissipated most of its pressure, flows axially to the fuel element. (U.S.)

  6. Variable volume combustor

    Science.gov (United States)

    Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

    2017-01-17

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

  7. Design and performance of atomizing nozzles for spray calcination of high-level wastes

    International Nuclear Information System (INIS)

    Miller, F.A.; Stout, L.A.

    1981-05-01

    A key aspect of high-level liquid-waste spray calcination is waste-feed atomization by using air atomizing nozzles. Atomization substantially increases the heat transfer area of the waste solution, which enhances rapid drying. Experience from the spray-calciner operations has demonstrated that nozzle flow conditions that produce 70-μ median-volume-diameter or smaller spray droplets are required for small-scale spray calciners (drying capacity less than 80 L/h). For large-scale calciners (drying capacity greater than 300 L/h), nozzle flow conditions that produce 100-μ median-volume-diameter or smaller spray droplets are required. Mass flow ratios of 0.2 to 0.4, depending on nozzle size, are required for proper operation of internal-mix atomizing nozzles. Both internal-mix and external-mix nozzles have been tested at PNL. Due to the lower airflow requirements and fewer large droplets produced, the internal-mix nozzle has been chosen for primary development in the spray calciner program at PNL. Several nozzle air-cap materials for internal-mix nozzles have been tested for wear resistance. Results show that nozzle air caps of stainless steel and Cer-vit (a machineable glass ceramic) are suceptible to rapid wear by abrasive slurries, whereas air caps of alumina and reaction-bonded silicon nitride show only slow wear. Longer-term testing is necessary to determine more accurately the actual frequency of nozzle replacement. Atomizing nozzle air caps of alumina are subject to fracture from thermal shock, whereas air caps of silicon nitride and Cer-vit are not. Fractured nozzles are held in place by the air-cap retaining ring and continue to atomize satisfactorily. Therefore, fractures caused by thermal shocking do not necessarily result in nozzle failure

  8. Modelling of hydrothermal characteristics of centrifugal nozzles

    International Nuclear Information System (INIS)

    Yarkho, A.A.; Omelchenko, M.P.; Borshchev, V.A.

    1990-01-01

    Presented for the first time is a method of recalculating the hydrothermal characteristics of centrifugal nozzles obtained in laboratory conditions for full-scale nozzles. From the experimental hydrothermal characteristics of nozzles observed in the laboratory it is allowed to calculate the hydrothermal characteristics of any other centrifugal nozzle whose diameter and dimensionless geometric characteristic are known

  9. Performance of an area variable MOS varicap weighted programmable CCD transversal filter

    OpenAIRE

    Bhattacharyya, A.B.; Shankarnarayan, L.; Kapur, N.; Wallinga, Hans

    1981-01-01

    The performance of an electrically programmable CCD transversal filter (PTF) is presented in which tap-weight multiplication is performed by a novel and compact on chip voltage controlled area variable MOS varicap.

  10. Numerical Simulation of Twin Nozzle Injectors

    OpenAIRE

    Milak, Dino

    2015-01-01

    Fuel injectors for marine applications have traditionally utilized nozzles with symmetric equispaced orifice configuration. But in light of the new marine emission legislations the twin nozzle concept has arisen. The twin nozzle differs from the conventional configuration by utilizing two closely spaced orifices to substitute each orifice in the conventional nozzle. Injector manufacturers regard twin nozzle injectors as a promising approach to facilitate stable spray patterns independent of t...

  11. Assessing the Impact of Socioeconomic Variables on Small Area Variations in Suicide Outcomes in England

    Directory of Open Access Journals (Sweden)

    Peter Congdon

    2012-12-01

    Full Text Available Ecological studies of suicide and self-harm have established the importance of area variables (e.g., deprivation, social fragmentation in explaining variations in suicide risk. However, there are likely to be unobserved influences on risk, typically spatially clustered, which can be modeled as random effects. Regression impacts may be biased if no account is taken of spatially structured influences on risk. Furthermore a default assumption of linear effects of area variables may also misstate or understate their impact. This paper considers variations in suicide outcomes for small areas across England, and investigates the impact on them of area socio-economic variables, while also investigating potential nonlinearity in their impact and allowing for spatially clustered unobserved factors. The outcomes are self-harm hospitalisations and suicide mortality over 6,781 Middle Level Super Output Areas.

  12. Design and Checkout of a High Speed Research Nozzle Evaluation Rig

    Science.gov (United States)

    Castner, Raymond S.; Wolter, John D.

    1997-01-01

    The High Flow Jet Exit Rig (HFJER) was designed to provide simulated mixed flow turbojet engine exhaust for one- seventh scale models of advanced High Speed Research test nozzles. The new rig was designed to be used at NASA Lewis Research Center in the Nozzle Acoustic Test Rig and the 8x6 Supersonic Wind Tunnel. Capabilities were also designed to collect nozzle thrust measurement, aerodynamic measurements, and acoustic measurements when installed at the Nozzle Acoustic Test Rig. Simulated engine exhaust can be supplied from a high pressure air source at 33 pounds of air per second at 530 degrees Rankine and nozzle pressure ratios of 4.0. In addition, a combustion unit was designed from a J-58 aircraft engine burner to provide 20 pounds of air per second at 2000 degrees Rankine, also at nozzle pressure ratios of 4.0. These airflow capacities were designed to test High Speed Research nozzles with exhaust areas from eighteen square inches to twenty-two square inches. Nozzle inlet flow measurement is available through pressure and temperature sensors installed in the rig. Research instrumentation on High Speed Research nozzles is available with a maximum of 200 individual pressure and 100 individual temperature measurements. Checkout testing was performed in May 1997 with a 22 square inch ASME long radius flow nozzle. Checkout test results will be summarized and compared to the stated design goals.

  13. Inter- and intrapatient variability of facial nerve response areas in the floor of the fourth ventricle.

    Science.gov (United States)

    Bertalanffy, Helmut; Tissira, Nadir; Krayenbühl, Niklaus; Bozinov, Oliver; Sarnthein, Johannes

    2011-03-01

    Surgical exposure of intrinsic brainstem lesions through the floor of the 4th ventricle requires precise identification of facial nerve (CN VII) fibers to avoid damage. To assess the shape, size, and variability of the area where the facial nerve can be stimulated electrophysiologically on the surface of the rhomboid fossa. Over a period of 18 months, 20 patients were operated on for various brainstem and/or cerebellar lesions. Facial nerve fibers were stimulated to yield compound muscle action potentials (CMAP) in the target muscles. Using the sites of CMAP yield, a detailed functional map of the rhomboid fossa was constructed for each patient. Lesions resected included 14 gliomas, 5 cavernomas, and 1 epidermoid cyst. Of 40 response areas mapped, 19 reached the median sulcus. The distance from the obex to the caudal border of the response area ranged from 8 to 27 mm (median, 17 mm). The rostrocaudal length of the response area ranged from 2 to 15 mm (median, 5 mm). Facial nerve response areas showed large variability in size and position, even in patients with significant distance between the facial colliculus and underlying pathological lesion. Lesions located close to the facial colliculus markedly distorted the response area. This is the first documentation of variability in the CN VII response area in the rhomboid fossa. Knowledge of this remarkable variability may facilitate the assessment of safe entry zones to the brainstem and may contribute to improved outcome following neurosurgical interventions within this sensitive area of the brain.

  14. Erosion wear of boron carbide ceramic nozzles by abrasive air-jets

    International Nuclear Information System (INIS)

    Deng Jianxin

    2005-01-01

    Boron carbide nozzles were produced by hot pressing. The erosion wear of this nozzle caused by abrasive particle impact was investigated by abrasive air-jets. Silica, silicon carbide and alumina powders with different hardness were used as the erodent abrasive particles. Results showed that the hardness of the erodent particles played an important role with respect to the erosion wear of the boron carbide nozzles. As the hardness of the erodent particles increases, there is a dramatic increase in erosion rate of the nozzles. The nozzle entrance area suffered from severe abrasive impact under large impact angles, and generated maximum tensile stresses. The wear mechanisms of boron carbide nozzle at this area appeared to be entirely brittle in nature with the evidence of large scale-chipping, and exhibited a brittle fracture induced removal process. While at the nozzle center wall section, most of the particles traveled parallel to the nozzle wall, and showed minimum tensile stresses. The wear mode in this area of the nozzle changed from impact to sliding erosion, and the wear mechanisms appeared to be the lateral cracking owing to a surface fatigue fracture mechanism

  15. Optimization of the size and shape of the set-in nozzle for a PWR reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Murtaza, Usman Tariq, E-mail: maniiut@yahoo.com; Javed Hyder, M., E-mail: hyder@pieas.edu.pk

    2015-04-01

    Highlights: • The size and shape of the set-in nozzle of the RPV have been optimized. • The optimized nozzle ensure the reduction of the mass around 198 kg per nozzle. • The mass of the RPV should be minimized for better fracture toughness. - Abstract: The objective of this research work is to optimize the size and shape of the set-in nozzle for a typical reactor pressure vessel (RPV) of a 300 MW pressurized water reactor. The analysis was performed by optimizing the four design variables which control the size and shape of the nozzle. These variables are inner radius of the nozzle, thickness of the nozzle, taper angle at the nozzle-cylinder intersection, and the point where taper of the nozzle starts from. It is concluded that the optimum design of the nozzle is the one that minimizes the two conflicting state variables, i.e., the stress intensity (Tresca yield criterion) and the mass of the RPV.

  16. Nozzle geometry for organic vapor jet printing

    Science.gov (United States)

    Forrest, Stephen R.; McGraw, Gregory

    2017-10-25

    A first device is provided. The device includes a print head. The print head further includes a first nozzle hermetically sealed to a first source of gas. The first nozzle has an aperture having a smallest dimension of 0.5 to 500 microns in a direction perpendicular to a flow direction of the first nozzle. At a distance from the aperture into the first nozzle that is 5 times the smallest dimension of the aperture of the first nozzle, the smallest dimension perpendicular to the flow direction is at least twice the smallest dimension of the aperture of the first nozzle.

  17. High inter-specimen variability of baseline data for the tibio-talar contact area.

    Science.gov (United States)

    Matricali, Giovanni A; Bartels, Ward; Labey, Luc; Dereymaeker, Greta Ph E; Luyten, Frank P; Vander Sloten, Jos

    2009-01-01

    The tibio-talar contact area has been widely investigated to monitor biomechanical changes due to articular incongruities or an altered loading. This study aims to investigate for the first time in a systematic way the extent of the inter-specimen variability of the tibio-talar contact area, and its repercussions when analyzing data concerning this parameter. Ten specimens were loaded to record the tibio-talar contact characteristics by use of pressure sensitive film. The size of the talar dome area, the size of the (normalized) tibio-talar contact area, the position of the tibio-talar contact area, and the shape of the latter were determined and analyzed. Inter-specimen variability was expressed as the coefficient of variation and was calculated for the datasets of previous studies as well. The size of the tibio-talar contact area showed a very high inter-specimen variability, as is the case in previous studies. This high variability persisted when a normalized tibio-talar contact area was calculated. The shape of the tibio-talar contact area showed some basic characteristics, but a high variation in details could be observed. Every specimen can be considered to have its own "ankle print". By this variability, articular incongruities are expected to have a different effect on local biomechanical characteristics in every single individual. Therefore, every single case has to be evaluated and reported for significant changes. In case of modeling, this also underscores the need to use subject specific models fed by sets of parameters derived from a series of single specimens.

  18. A tool for protected area management: multivariate control charts 'cope' with rare variable communities.

    Science.gov (United States)

    Stringell, Thomas B; Bamber, Roger N; Burton, Mark; Lindenbaum, Charles; Skates, Lucie R; Sanderson, William G

    2013-06-01

    Performance assessment, impact detection, and the assessment of regulatory compliance are common scientific problems for the management of protected areas. Some habitats in protected areas, however, are rare and/or variable and are not often selected for study by ecologists because they preclude comparison with controls and high community variability makes meaningful change detection difficult. Shallow coastal saline lagoons are habitats that experience comparatively high levels of stress due to high physical variability. Lagoons are rare, declining habitats found in coastal regions throughout Europe (and elsewhere) where they are identified as one of the habitats most in need of protected area management. The infauna in the sediments of 25 lagoons were sampled. Temporal and spatial variation in three of these [protected] lagoons was investigated further over 5 years. In a multivariate analysis of community structure similarities were found between some lagoons, but in other cases communities were unique or specific to only two sites. The protected lagoons with these unique/specific communities showed significant temporal and spatial variation, yet none of the changes observed were attributed to human impacts and were interpreted as inherent variability. Multivariate control charts can operate without experimental controls and were used to assess community changes within the context of 'normal' lagoon variability. The aim of control chart analysis is to characterize background variability in a parameter and identify when a new observation deviates more than expected. In only 1 year was variability more than expected and corresponded with the coldest December in over 100 years. Multivariate control charts are likely to have wide application in the management of protected areas and other natural systems where variability and/or rarity preclude conventional analytical and experimental approaches but where assessments of condition, impact or regulatory compliance are

  19. Analysis of experiments performed at University of Hannover with Relap5/Mod2 and Cathare codes on fluid dynamic effects in the fuel element top nozzle area during refilling and reflooding

    International Nuclear Information System (INIS)

    Ambrosini, W.; D'Auria, F.; Di Marco, P.; Fantappie, G.; Giot, G.; Emmerechts, D.; Seynhaeve, J.M.; Zhang, J.

    1989-11-01

    The experimental data of flooding and CCFL in the fuel element top nozzle area collected at the University of Hannover have been analyzed with RELAP5/MOD2 and CATHARE V.1.3 codes. Preliminary sensitivity calculations have been performed to evaluate the influence of various parameters and code options on the results. However, an a priori rational assessment procedure has been performed for those parameters non specific in experimental data (e.g. energy loss coefficients in flow restrictions). This procedure is based on single phase flow pressure drops and no further tuning has been performed to fit experimental data. The reported experimental data and some others demonstrate the complex relation-ship among the involved physical quantities (film thickness, pressure drop etc.) even in a simple geometrical condition with well defined boundary conditions. In the application of the two advanced codes to the selected CCFL experiments it appears that sophisticated models do not simulate satisfactorily the measured phenomena mainly when situations similar to nuclear reactors are dealt with (rod bundles). This result should be evaluated considering that: - dimensional phenomena occurring in flooding experiments are not well reproducible with one dimensional models implemented in the two codes; - a rational and reproducible procedure has been used to fix some boundary conditions (K-tuning); there is the evidence that more tuning can be used to get results closer to the experimental ones in each specific situation; - the uncertainty bands in measured experimental results are not (entirely) specified. The work performed demonstrated that further applications to CCFL experiments of present codes appear to be unuseful. New models should be tested and implemented before any attempt to reproduce CCFL in experimental facilities by system codes

  20. Multielement suppressor nozzles for thrust augmentation systems.

    Science.gov (United States)

    Lawrence, R. L.; O'Keefe, J. V.; Tate, R. B.

    1972-01-01

    The noise reduction and nozzle performance characteristics of large-scale, high-aspect-ratio multielement nozzle arrays operated at low velocities were determined by test. The nozzles are selected for application to high-aspect-ratio augmentor suppressors to be used for augmentor wing airplanes. Significant improvements in noise characteristics for multielement nozzles over those of round or high-aspect-ratio slot nozzles are obtained. Elliptical noise patterns typical of slot nozzles are presented for high-aspect-ratio multielement nozzle arrays. Additional advantages are available in OASPL noise reduction from the element size and spacing. Augmentor-suppressor systems can be designed for maximum beam pattern directivity and frequency spectrum shaping advantages. Measurements of the nozzle wakes show a correlation with noise level data and frequency spectrum peaks. The noise and jet wake results are compared with existing prediction procedures based on empirical jet flow equations, Lighthill relationships, Strouhal number, and empirical shock-induced screech noise effects.

  1. Influence of weather and climate variables on the basal area growth of individual shortleaf pine trees

    Science.gov (United States)

    Pradip Saud; Thomas B. Lynch; Duncan S. Wilson; John Stewart; James M. Guldin; Bob Heinemann; Randy Holeman; Dennis Wilson; Keith Anderson

    2015-01-01

    An individual-tree basal area growth model previously developed for even-aged naturally occurring shortleaf pine trees (Pinus echinata Mill.) in western Arkansas and southeastern Oklahoma did not include weather variables. Individual-tree growth and yield modeling of shortleaf pine has been carried out using the remeasurements of over 200 plots...

  2. Turbomachine combustor nozzle including a monolithic nozzle component and method of forming the same

    Science.gov (United States)

    Stoia, Lucas John; Melton, Patrick Benedict; Johnson, Thomas Edward; Stevenson, Christian Xavier; Vanselow, John Drake; Westmoreland, James Harold

    2016-02-23

    A turbomachine combustor nozzle includes a monolithic nozzle component having a plate element and a plurality of nozzle elements. Each of the plurality of nozzle elements includes a first end extending from the plate element to a second end. The plate element and plurality of nozzle elements are formed as a unitary component. A plate member is joined with the nozzle component. The plate member includes an outer edge that defines first and second surfaces and a plurality of openings extending between the first and second surfaces. The plurality of openings are configured and disposed to register with and receive the second end of corresponding ones of the plurality of nozzle elements.

  3. Simulation of a Downsized FDM Nozzle

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Pimentel, Rodrigo; Pedersen, David B.

    2015-01-01

    This document discusses the simulat-ion of a downsized nozzle for fused deposition modelling (FDM), namely the E3D HotEnd Extruder with manufactured diameters of 200-400 μm in the nozzle tip. The nozzle has been simulated in terms of heat transfer and fluid flow giving an insight into the physical...

  4. Technical specifications of variable speed motors for negative pressure control in hot cell area

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Duk; Bang, H. S.; Cho, W. K

    2002-01-01

    Hot cells are the facilities for handling the high radioactive materials and various R and D activities are performed using hot cells. Therefore the control of air flow in hot cell area is very important technology and it is started with the variable speed motor(VSM) controlling the air handling system in that area. This report describes various technical aspects of VS motors and will be useful for understanding the practical technologies of VS motors and also for optimization of the negative pressure controls in hot cell area.

  5. Variability in effective radiating area and output power of new ultrasound transducers at 3 MHz.

    Science.gov (United States)

    Johns, Lennart D; Straub, Stephen J; Howard, Samuel M

    2007-01-01

    Spatial average intensity (SAI) is often used by clinicians to gauge therapeutic ultrasound dosage, yet SAI measures are not directly regulated by US Food and Drug Administration (FDA) standards. Current FDA guidelines permit a possible 50% to 150% minimum to maximum range of SAI values, potentially contributing to variability in clinical outcomes. To measure clinical values that describe ultrasound transducers and to determine the degree of intramanufacturer and intermanufacturer variability in effective radiating area, power, and SAI when the transducer is functioning at 3 MHz. A descriptive and interferential approach was taken to this quasi-experimental design. Measurement laboratory. Sixty-six 5-cm(2) ultrasound transducers were purchased from 6 different manufacturers. All transducers were calibrated and then assessed using standardized measurement techniques; SAI was normalized to account for variability in effective radiating area, resulting in an nSAI. Effective radiating area, power, and nSAI. All manufacturers with the exception of Omnisound (P = .534) showed a difference between the reported and measured effective radiating area values (P nSAI (P < .05) than all other manufacturers functioning at 3 MHz. Intramanufacturer variability in SAI ranged from 16% to 35%, and intermanufacturer variability ranged from 22% to 61%. Clinicians should consider treatment values of each individual transducer, regardless of the manufacturer. In addition, clinicians should scrutinize the power calibration and recalibration record of the transducer and adjust clinical settings as needed for the desired level of heating. Our data may aid in explaining the reported heating differences among transducers from different manufacturers. Stricter FDA standards regarding effective radiating area and total power are needed, and standards regulating SAI should be established.

  6. Process for manufacturing separating nozzles

    International Nuclear Information System (INIS)

    Bier, W.; Linder, G.; Mayer, E.

    1979-01-01

    The final form of the basic body and the unit consisting of the nozzle and peeling orifice provides immovable fixing of these parts. Surfaces of various components can then be milled, using milling tools, in one operation. Assembly can be made automatic. (DG) [de

  7. Nozzle for electric dispersion reactor

    Science.gov (United States)

    Sisson, W.G.; Basaran, O.A.; Harris, M.T.

    1995-11-07

    A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 4 figs.

  8. Shock unsteadiness in a thrust optimized parabolic nozzle

    Science.gov (United States)

    Verma, S. B.

    2009-07-01

    This paper discusses the nature of shock unsteadiness, in an overexpanded thrust optimized parabolic nozzle, prevalent in various flow separation modes experienced during start up {(δ P0 /δ t > 0)} and shut down {(δ P0/δ t The results are based on simultaneously acquired data from real-time wall pressure measurements using Kulite pressure transducers, high-speed schlieren (2 kHz) of the exhaust flow-field and from strain-gauges installed on the nozzle bending tube. Shock unsteadiness in the separation region is seen to increase significantly just before the onset of each flow transition, even during steady nozzle operation. The intensity of this measure ( rms level) is seen to be strongly influenced by relative locations of normal and overexpansion shock, the decrease in radial size of re-circulation zone in the back-flow region, and finally, the local nozzle wall contour. During restricted shock separation, the pressure fluctuations in separation region exhibit periodic characteristics rather than the usually observed characteristics of intermittent separation. The possible physical mechanisms responsible for the generation of flow unsteadiness in various separation modes are discussed. The results are from an experimental study conducted in P6.2 cold-gas subscale test facility using a thrust optimized parabolic nozzle of area-ratio 30.

  9. A computational investigation on the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development in diesel injector nozzles

    International Nuclear Information System (INIS)

    Molina, S.; Salvador, F.J.; Carreres, M.; Jaramillo, D.

    2014-01-01

    Highlights: • The influence of elliptical orifices on the inner nozzle flow is compared. • Five nozzles with different elliptical and circular orifices are simulated. • Differences in the flow coefficients and cavitation morphology are observed. • Horizontal axis orifices are ease to cavitate, with a higher discharge coefficient. • A better mixing process quality is expected for the horizontal major axis nozzles. - Abstract: In this paper a computational study was carried out in order to investigate the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development. With this aim, a large number of injection conditions have been simulated and analysed for 5 different nozzles: four nozzles with different elliptical orifices and one standard nozzle with circular orifices. The four elliptical nozzles differ from each other in the orientation of the major axis (vertical or horizontal) and in the eccentricity value, but keeping the same outlet section in all cases. The comparison has been made in terms of mass flow, momentum flux and other important non-dimensional parameters which help to describe the behaviour of the inner nozzle flow: discharge coefficient (C d ), area coefficient (C a ) and velocity coefficient (C v ). The simulations have been done with a code able to simulate the flow under either cavitating or non-cavitating conditions. This code has been previously validated using experimental measurements over the standard nozzle with circular orifices. The main results of the investigation have shown how the different geometries modify the critical cavitation conditions as well as the discharge coefficient and the effective velocity. In particular, elliptical geometries with vertically oriented major axis are less prone to cavitate and have a lower discharge coefficient, whereas elliptical geometries with horizontally oriented major axis are more prone to cavitate and show a higher discharge coefficient

  10. Annular Internal-External-Expansion Rocket Nozzles for Large Booster Applications

    Science.gov (United States)

    Connors, James F.; Cubbison, Robert W.; Mitchell, Glenn A.

    1961-01-01

    For large-thrust booster applications, annular rocket nozzles employing both internal and external expansion are investigated. In these nozzles, free-stream air flows through the center as well as around the outside of the exiting jet. Flaps for deflecting the rocket exhaust are incorporated on the external-expansion surface for thrust-vector control. In order to define nozzle off-design performance, thrust vectoring effectiveness, and external stream effects, an experimental investigation was conducted on two annular nozzles with area ratios of 15 and 25 at Mach 0, 2, and 3 in the Lewis 10- by 10-foot wind tunnel. Air, pressurized to 600 pounds per square inch absolute, was used to simulate the exhaust flow. For a nozzle-pressure-ratio range of 40 to 1000, the ratio of actual to ideal thrust was essentially constant at 0.98 for both nozzles. Compared with conventional convergent-divergent configurations on hypothetical boost missions, the performance gains of the annular nozzle could yield significant orbital payload increases (possibly 8 to 17 percent). A single flap on the external-expansion surface of the area-ratio-25 annular nozzle produced a side force equal to 4 percent of the axial force with no measurable loss in axial thrust.

  11. Nozzle geometry variations on the discharge coefficient

    Directory of Open Access Journals (Sweden)

    M.M.A. Alam

    2016-03-01

    Full Text Available Numerical works have been conducted to investigate the effect of nozzle geometries on the discharge coefficient. Several contoured converging nozzles with finite radius of curvatures, conically converging nozzles and conical divergent orifices have been employed in this investigation. Each nozzle and orifice has a nominal exit diameter of 12.7×10−3 m. A 3rd order MUSCL finite volume method of ANSYS Fluent 13.0 was used to solve the Reynolds-averaged Navier–Stokes equations in simulating turbulent flows through various nozzle inlet geometries. The numerical model was validated through comparison between the numerical results and experimental data. The results obtained show that the nozzle geometry has pronounced effect on the sonic lines and discharge coefficients. The coefficient of discharge was found differ from unity due to the non-uniformity of flow parameters at the nozzle exit and the presence of boundary layer as well.

  12. Compressed air noise reductions from using advanced air gun nozzles in research and development environments.

    Science.gov (United States)

    Prieve, Kurt; Rice, Amanda; Raynor, Peter C

    2017-08-01

    The aims of this study were to evaluate sound levels produced by compressed air guns in research and development (R&D) environments, replace conventional air gun models with advanced noise-reducing air nozzles, and measure changes in sound levels to assess the effectiveness of the advanced nozzles as engineering controls for noise. Ten different R&D manufacturing areas that used compressed air guns were identified and included in the study. A-weighted sound level and Z-weighted octave band measurements were taken simultaneously using a single instrument. In each area, three sets of measurements, each lasting for 20 sec, were taken 1 m away and perpendicular to the air stream of the conventional air gun while a worker simulated typical air gun work use. Two different advanced noise-reducing air nozzles were then installed. Sound level and octave band data were collected for each of these nozzles using the same methods as for the original air guns. Both of the advanced nozzles provided sound level reductions of about 7 dBA, on average. The highest noise reductions measured were 17.2 dBA for one model and 17.7 dBA for the other. In two areas, the advanced nozzles yielded no sound level reduction, or they produced small increases in sound level. The octave band data showed strong similarities in sound level among all air gun nozzles within the 10-1,000 Hz frequency range. However, the advanced air nozzles generally had lower noise contributions in the 1,000-20,000 Hz range. The observed decreases at these higher frequencies caused the overall sound level reductions that were measured. Installing new advanced noise-reducing air nozzles can provide large sound level reductions in comparison to existing conventional nozzles, which has direct benefit for hearing conservation efforts.

  13. Spatial variability of soil potassium in sugarcane areas subjected to the application of vinasse

    Directory of Open Access Journals (Sweden)

    LAÉRCIO A. DE CARVALHO

    2014-12-01

    Full Text Available When deposited on land the vinasse can promote improvement in fertility, however, often fertilizer application occurs in areas considered homogeneous, without taking into account the variability of the soil. The objective of this study was to evaluate the effect of vinasse application on potassium content in two classes of soils cultivated with sugarcane, and characterize the spatial variability of soil using geostatistical techniques. In the 2010 and 2011 crop year, soil samples were collected from an experimental grid at 0-0.2 and 0.2-0.4 m depth in three soils cultivated with sugarcane, totaling 90 samplings in each grid, for the determination of pH, calcium (Ca, magnesium (Mg, potassium (K, phosphorus (P, aluminum (Al and potential acidity (H + Al. The data have been submitted to analysis of descriptive statistics and the K attribute was subjected to geostatistical analysis. The coefficient of variation indicated medium and high variability of K for the three soils. The results showed that the spatial dependence of K increased in depth to FRce and decreased to PHlv, indicating that the attribute could have followed the pattern of distribution of clay in depth. The investigation of the spatial variability of K on the surface and subsurface soils provided the definition of management zones with different levels of fertility, which can be organized into sub-areas for a more efficient management of the resources and the environment.

  14. Climate variability and impacts on east African livestock herders: The Maasai of Ngorongoro Conservation Area, Tanzania

    OpenAIRE

    Galvin, K.A.; Thornton, P.K.; Boone, R.B.; Sunderland, J.

    2004-01-01

    Metadata only record East African pastoral adaptation and vulnerability to climate variability and climate change is assessed, using data from decision-making processes and ecological data of the Maasai of Ngorongoro Conservation Area as an example. The paper uses integrated modeling, linking PHEWS, a household model, to SAVANNA, an ecosystem model to look at the effects of drought and a series of wet years on the well-being of Maasai pastoralists. Model results suggest that the ecosystem ...

  15. Area-averaged surface fluxes and their time-space variability over the FIFE experimental domain

    Science.gov (United States)

    Smith, E. A.; Hsu, A. Y.; Crosson, W. L.; Field, R. T.; Fritschen, L. J.; Gurney, R. J.; Kanemasu, E. T.; Kustas, W. P.; Nie, D.; Shuttleworth, W. J.

    1992-01-01

    The underlying mean and variance properties of surface net radiation, sensible-latent heat fluxes and soil heat flux are studied over the densely instrumented grassland region encompassing FIFE. Flux variability is discussed together with the problem of scaling up to area-averaged fluxes. Results are compared and contrasted for cloudy and clear situations and examined for the influence of surface-induced biophysical controls (burn and grazing treatments) and topographic controls (aspect ratios and slope factors).

  16. Controllable deposition distance of aligned pattern via dual-nozzle near-field electrospinning

    Science.gov (United States)

    Wang, Zhifeng; Chen, Xindu; Zeng, Jun; Liang, Feng; Wu, Peixuan; Wang, Han

    2017-03-01

    For large area micro/nano pattern printing, multi-nozzle electrohydrodynamic (EHD) printing setup is an efficient method to boost productivity in near-field electrospinning (NFES) process. And controlling EHD multi-jet accurate deposition under the interaction of nozzles and other parameters are crucial concerns during the process. The influence and sensitivity of various parameters such as the needle length, needle spacing, electrode-to-collector distance, voltage etc. on the direct-write patterning performance was investigated by orthogonal experiments with dual-nozzle NFES setup, and then the deposition distance estimated based on a novel model was compared with measurement results and proven. More controllable deposition distance and much denser of aligned naofiber can be achieved by rotating the dual-nozzle setup. This study can be greatly contributed to estimate the deposition distance and helpful to guide the multi-nozzle NFES process to accurate direct-write pattern in manufacturing process in future.

  17. Spatial Variability of Sources and Mixing State of Atmospheric Particles in a Metropolitan Area.

    Science.gov (United States)

    Ye, Qing; Gu, Peishi; Li, Hugh Z; Robinson, Ellis S; Lipsky, Eric; Kaltsonoudis, Christos; Lee, Alex K Y; Apte, Joshua S; Robinson, Allen L; Sullivan, Ryan C; Presto, Albert A; Donahue, Neil M

    2018-05-30

    Characterizing intracity variations of atmospheric particulate matter has mostly relied on fixed-site monitoring and quantifying variability in terms of different bulk aerosol species. In this study, we performed ground-based mobile measurements using a single-particle mass spectrometer to study spatial patterns of source-specific particles and the evolution of particle mixing state in 21 areas in the metropolitan area of Pittsburgh, PA. We selected sampling areas based on traffic density and restaurant density with each area ranging from 0.2 to 2 km 2 . Organics dominate particle composition in all of the areas we sampled while the sources of organics differ. The contribution of particles from traffic and restaurant cooking varies greatly on the neighborhood scale. We also investigate how primary and aged components in particles mix across the urban scale. Lastly we quantify and map the particle mixing state for all areas we sampled and discuss the overall pattern of mixing state evolution and its implications. We find that in the upwind and downwind of the urban areas, particles are more internally mixed while in the city center, particle mixing state shows large spatial heterogeneity that is mostly driven by emissions. This study is to our knowledge, the first study to perform fine spatial scale mapping of particle mixing state using ground-based mobile measurement and single-particle mass spectrometry.

  18. Interpolating a consumption variable for scaling and generalizing potential population pressure on urbanizing natural areas

    Science.gov (United States)

    Varanka, Dalia; Jiang, Bin; Yao, Xiaobai

    2010-01-01

    Measures of population pressure, referring in general to the stress upon the environment by human consumption of resources, are imperative for environmental sustainability studies and management. Development based on resource consumption is the predominant factor of population pressure. This paper presents a spatial model of population pressure by linking consumption associated with regional urbanism and ecosystem services. Maps representing relative geographic degree and extent of natural resource consumption and degree and extent of impacts on surrounding areas are new, and this research represents the theoretical research toward this goal. With development, such maps offer a visualization tool for planners of various services, amenities for people, and conservation planning for ecologist. Urbanization is commonly generalized by census numbers or impervious surface area. The potential geographical extent of urbanism encompasses the environmental resources of the surrounding region that sustain cities. This extent is interpolated using kriging of a variable based on population wealth data from the U.S. Census Bureau. When overlayed with land-use/land-cover data, the results indicate that the greatest estimates of population pressure fall within mixed forest areas. Mixed forest areas result from the spread of cedar woods in previously disturbed areas where further disturbance is then suppressed. Low density areas, such as suburbanization and abandoned farmland are characteristic of mixed forest areas.

  19. Fluid flow nozzle energy harvesters

    Science.gov (United States)

    Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Winn, Tyler; Tosi, Luis Phillipe; Colonius, Tim

    2015-04-01

    Power generation schemes that could be used downhole in an oil well to produce about 1 Watt average power with long-life (decades) are actively being developed. A variety of proposed energy harvesting schemes could be used to extract energy from this environment but each of these has their own limitations that limit their practical use. Since vibrating piezoelectric structures are solid state and can be driven below their fatigue limit, harvesters based on these structures are capable of operating for very long lifetimes (decades); thereby, possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. An initial survey [1] identified that spline nozzle configurations can be used to excite a vibrating piezoelectric structure in such a way as to convert the abundant flow energy into useful amounts of electrical power. This paper presents current flow energy harvesting designs and experimental results of specific spline nozzle/ bimorph design configurations which have generated suitable power per nozzle at or above well production analogous flow rates. Theoretical models for non-dimensional analysis and constitutive electromechanical model are also presented in this paper to optimize the flow harvesting system.

  20. Assessing variability and long-term trends in burned area by merging multiple satellite fire products

    Directory of Open Access Journals (Sweden)

    L. Giglio

    2010-03-01

    Full Text Available Long term, high quality estimates of burned area are needed for improving both prognostic and diagnostic fire emissions models and for assessing feedbacks between fire and the climate system. We developed global, monthly burned area estimates aggregated to 0.5° spatial resolution for the time period July 1996 through mid-2009 using four satellite data sets. From 2001–2009, our primary data source was 500-m burned area maps produced using Moderate Resolution Imaging Spectroradiometer (MODIS surface reflectance imagery; more than 90% of the global area burned during this time period was mapped in this fashion. During times when the 500-m MODIS data were not available, we used a combination of local regression and regional regression trees developed over periods when burned area and Terra MODIS active fire data were available to indirectly estimate burned area. Cross-calibration with fire observations from the Tropical Rainfall Measuring Mission (TRMM Visible and Infrared Scanner (VIRS and the Along-Track Scanning Radiometer (ATSR allowed the data set to be extended prior to the MODIS era. With our data set we estimated that the global annual area burned for the years 1997–2008 varied between 330 and 431 Mha, with the maximum occurring in 1998. We compared our data set to the recent GFED2, L3JRC, GLOBCARBON, and MODIS MCD45A1 global burned area products and found substantial differences in many regions. Lastly, we assessed the interannual variability and long-term trends in global burned area over the past 13 years. This burned area time series serves as the basis for the third version of the Global Fire Emissions Database (GFED3 estimates of trace gas and aerosol emissions.

  1. PIV Measurements of Chevrons on F400-Series Tactical Aircraft Nozzle Model

    Science.gov (United States)

    Bridges, James; Wernet, Mark P.; Frate, Franco C.

    2011-01-01

    Reducing noise of tactical jet aircraft has taken on fresh urgency as core engine technologies allow higher specific-thrust engines and as society become more concerned for the health of its military workforce. Noise reduction on this application has lagged the commercial field as incentives for quieting military aircraft have not been as strong as in their civilian counterparts. And noise reduction strategies employed on civilian engines may not be directly applicable due to the differences in exhaust system architecture and mission. For instance, the noise reduction technology of chevrons, examined in this study, will need to be modified to take into account the special features of tactical aircraft nozzles. In practice, these nozzles have divergent slats that are tied to throttle position, and at take off the jet flow is highly overexpanded as the nozzle is optimized for cruise altitude rather than sea level. In simple oil flow visualization experiments conducted at the onset of the current test program flow barely stays attached at end of nozzle at takeoff conditions. This adds a new twist to the design of chevrons. Upon reaching the nozzle exit the flow shrinks inward radially, meaning that for a chevron to penetrate the flow it must extend much farther away from the baseline nozzle streamline. Another wrinkle is that with a variable divergence angle on the nozzle, the effective penetration will differ with throttle position and altitude. The final note of realism introduced in these experiments was to simulate the manner in which bypass flow is bled into the nozzle wall in real engines to cool the nozzle, which might cause very fat boundary layer at exit. These factors, along with several other issues specific to the application of chevrons to convergent-divergent nozzles have been explored with particle image velocimetry measurements and are presented in this paper.

  2. Off-design performance loss model for radial turbines with pivoting, variable-area stators

    Science.gov (United States)

    Meitner, P. L.; Glassman, A. J.

    1980-01-01

    An off-design performance loss model was developed for variable stator (pivoted vane), radial turbines through analytical modeling and experimental data analysis. Stator loss is determined by a viscous loss model; stator vane end-clearance leakage effects are determined by a clearance flow model. Rotor loss coefficient were obtained by analyzing the experimental data from a turbine rotor previously tested with six stators having throat areas from 20 to 144 percent of design area and were correlated with stator-to-rotor throat area ratio. An incidence loss model was selected to obtain best agreement with experimental results. Predicted turbine performance is compared with experimental results for the design rotor as well as with results for extended and cutback versions of the rotor. Sample calculations were made to show the effects of stator vane end-clearance leakage.

  3. Variability of soil fertility properties in areas planted to sugarcane in the State of Goias, Brazil

    Directory of Open Access Journals (Sweden)

    José Avelino Cardoso

    2014-04-01

    Full Text Available Soil sampling should provide an accurate representation of a given area so that recommendations for amendments of soil acidity, fertilization and soil conservation may be drafted to increase yield and improve the use of inputs. The aim of this study was to evaluate the variability of soil fertility properties of Oxisols in areas planted to sugarcane in the State of Goias, Brazil. Two areas of approximately 8,100 m² each were selected, representing two fields of the Goiasa sugarcane mill in Goiatuba. The sugarcane crop had a row spacing of 1.5 m and subsamples were taken from 49 points in the row and 49 between the row with a Dutch auger at depths of 0.0-0.2 and 0.2-0.4 m, for a total of 196 subsamples for each area. The samples were individually subjected to chemical analyses of soil fertility (pH in CaCl2, potential acidity, organic matter, P, K, Ca and Mg and particle size analysis. The number of subsamples required to compose a sample within the acceptable ranges of error of 5, 10, 20 and 40 % of each property were computed from the coefficients of variation and the Student t-value for 95 % confidence. The soil properties under analysis exhibited different variabilities: high (P and K, medium (potential acidity, Ca and Mg and low (pH, organic matter and clay content. Most of the properties analyzed showed an error of less than 20 % for a group of 20 subsamples, except for P and K, which were capable of showing an error greater than 40 % around the mean. The extreme variability in phosphorus, particularly at the depth of 0.2-0.4 m, attributed to banded application of high rates of P fertilizers at planting, places limitations on assessment of its availability due to the high number of subsamples required for a composite sample.

  4. Computer Graphic Design Using Auto-CAD and Plug Nozzle Research

    Science.gov (United States)

    Rogers, Rayna C.

    2004-01-01

    The purpose of creating computer generated images varies widely. They can be use for computational fluid dynamics (CFD), or as a blueprint for designing parts. The schematic that I will be working on the summer will be used to create nozzles that are a part of a larger system. At this phase in the project, the nozzles needed for the systems have been fabricated. One part of my mission is to create both three dimensional and two dimensional models on Auto-CAD 2002 of the nozzles. The research on plug nozzles will allow me to have a better understanding of how they assist in the thrust need for a missile to take off. NASA and the United States military are working together to develop a new design concept. On most missiles a convergent-divergent nozzle is used to create thrust. However, the two are looking into different concepts for the nozzle. The standard convergent-divergent nozzle forces a mixture of combustible fluids and air through a smaller area in comparison to where the combination was mixed. Once it passes through the smaller area known as A8 it comes out the end of the nozzle which is larger the first or area A9. This creates enough thrust for the mechanism whether it is an F-18 fighter jet or a missile. The A9 section of the convergent-divergent nozzle has a mechanism that controls how large A9 can be. This is needed because the pressure of the air coming out nozzle must be equal to that of the ambient pressure other wise there will be a loss of performance in the machine. The plug nozzle however does not need to have an A9 that can vary. When the air flow comes out it can automatically sense what the ambient pressure is and will adjust accordingly. The objective of this design is to create a plug nozzle that is not as complicated mechanically as it counterpart the convergent-divergent nozzle.

  5. Spatial representation and cognitive modulation of response variability in the lateral intraparietal area priority map.

    Science.gov (United States)

    Falkner, Annegret L; Goldberg, Michael E; Krishna, B Suresh

    2013-10-09

    The lateral intraparietal area (LIP) in the macaque contains a priority-based representation of the visual scene. We previously showed that the mean spike rate of LIP neurons is strongly influenced by spatially wide-ranging surround suppression in a manner that effectively sharpens the priority map. Reducing response variability can also improve the precision of LIP's priority map. We show that when a monkey plans a visually guided delayed saccade with an intervening distractor, variability (measured by the Fano factor) decreases both for neurons representing the saccade goal and for neurons representing the broad spatial surround. The reduction in Fano factor is maximal for neurons representing the saccade goal and steadily decreases for neurons representing more distant locations. LIP Fano factor changes are behaviorally significant: increasing expected reward leads to lower variability for the LIP representation of both the target and distractor locations, and trials with shorter latency saccades are associated with lower Fano factors in neurons representing the surround. Thus, the LIP Fano factor reflects both stimulus and behavioral engagement. Quantitative modeling shows that the interaction between mean spike count and target-receptive field (RF) distance in the surround during the predistractor epoch is multiplicative: the Fano factor increases more steeply with mean spike count further away from the RF. A negative-binomial model for LIP spike counts captures these findings quantitatively, suggests underlying mechanisms based on trial-by-trial variations in mean spike rate or burst-firing patterns, and potentially provides a principled framework to account simultaneously for the previously observed unsystematic relationships between spike rate and variability in different brain areas.

  6. PULSED MOLECULAR BEAM PRODUCTION WITH NOZZLES

    Energy Technology Data Exchange (ETDEWEB)

    Hagena, Otto-Friedrich

    1963-05-15

    Molecular beam experiments that can be carried out in pulsed operation may be performed at considerably reduced expense for apparatus if, for pulse generation, the gas supply to the beam production system is interrupted as opposed to the usual steady molecular beam. This technique is studied by measuring intensity vs time of molecular beam impulses of varying length, how fast and through which intermediate states the initial intensity of the impulse attains equilibrium, and in which way the intensity of the molecular-beam impulse is affected by the pulse length and by increasing pressure in the first pressure stage. For production of pulses, a magnetically actuated, quick shutting, valve is used whose scaling area is the inlet cone of the nozzle used for the beam generation. The shortest pulses produced had a pulse length of 1.6 ms. (auth)

  7. Experimental investigation on motive nozzle throat diameter for an ejector expansion refrigeration system

    International Nuclear Information System (INIS)

    Bilir Sag, Nagihan; Ersoy, H. Kursad

    2016-01-01

    Highlights: • Effects of nozzle throat diameter and its location on performance were investigated. • The nozzle has an optimum throat diameter under the experiment condition. • The maximum performance has been achieved by using optimum nozzle throat diameter. • The variation of nozzle throat diameter with condenser water inlet temperature was examined. • Motive nozzle has no optimum position in the ejector refrigeration system. - Abstract: In this study, ejector was used to reduce throttling losses in a vapour compression refrigeration system. Effects on system performance of throat diameter and position of motive nozzle of ejector were investigated experimentally. An ejector was designed based on the established mathematical model and manufactured. The experiments were carried out by using different primary nozzle throat diameters. The experiments were further conducted by changing condenser water inlet temperature, which is one of the external parameters. The experimental results of the ejector system and those of the classic system were compared under same external operating conditions and for the same cooling capacity. In order to obtain same external operating conditions in both systems, the inlet conditions of the brine supplied to the evaporator and inlet water conditions (flow rate and temperature) to the condenser were kept constant. Maximum performance was obtained when the primary nozzle throat diameter was 2.3 mm within the areas considered in this study. When compared, it was experimentally determined that the ejector system that uses the optimum motive nozzle throat diameter exhibits higher COP than the classic system by 5–13%. Furthermore, it was found that the variation of coefficient of performance based on position of motive nozzle in two-phase ejector expander refrigeration cycle is lower than 1%.

  8. Laval nozzles for cluster-jet targets

    Energy Technology Data Exchange (ETDEWEB)

    Grieser, Silke; Bonaventura, Daniel; Hergemoeller, Ann-Katrin; Hetz, Benjamin; Koehler, Esperanza; Lessmann, Lukas; Khoukaz, Alfons [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster, 48149 Muenster (Germany)

    2016-07-01

    Cluster-jet targets are highly suited for storage ring experiments due to the fact that they provide high and constant beam densities. Therefore, a cluster-jet target is planned to be the first internal target for the PANDA experiment at FAIR. A cluster source generates a continuous flow of cryogenic solid clusters by the expansion of pre-cooled gases within fine Laval nozzles. For the production of clusters the geometry of the nozzle is crucial. The production of such nozzles with their complex inner geometry represents a major technical challenge. The possibility to produce new fine Laval nozzles ensures the operation of cluster-jet targets, e.g. for the PANDA experiment, and opens the way for future investigations on the cluster production process to match the required targets performance. Optimizations on the recently developed production process and the fabrication of new glass nozzles were done. Initial measurements of these nozzles at the PANDA cluster-jet target prototype and the investigation of the cluster beam origin within the nozzle will be presented and discussed. For the future more Laval nozzles with different geometries will be produced and additional measurements with these new nozzles at the PANDA cluster-jet target prototype towards higher performance will be realized.

  9. Fractal analysis of agricultural nozzles spray

    Directory of Open Access Journals (Sweden)

    Francisco Agüera

    2012-02-01

    Full Text Available Fractal scaling of the exponential type is used to establish the cumulative volume (V distribution applied through agricultural spray nozzles in size x droplets, smaller than the characteristic size X. From exponent d, we deduced the fractal dimension (Df which measures the degree of irregularity of the medium. This property is known as 'self-similarity'. Assuming that the droplet set from a spray nozzle is self-similar, the objectives of this study were to develop a methodology for calculating a Df factor associated with a given nozzle and to determine regression coefficients in order to predict droplet spectra factors from a nozzle, taking into account its own Df and pressure operating. Based on the iterated function system, we developed an algorithm to relate nozzle types to a particular value of Df. Four nozzles and five operating pressure droplet size characteristics were measured using a Phase Doppler Particle Analyser (PDPA. The data input consisted of droplet size spectra factors derived from these measurements. Estimated Df values showed dependence on nozzle type and independence of operating pressure. We developed an exponential model based on the Df to enable us to predict droplet size spectra factors. Significant coefficients of determination were found for the fitted model. This model could prove useful as a means of comparing the behavior of nozzles which only differ in not measurable geometric parameters and it can predict droplet spectra factors of a nozzle operating under different pressures from data measured only in extreme work pressures.

  10. Pengaruh Variasi Lip Thickness pada Nozzle Terpancung terhadap Karakteristik Api Pembakaran Difusi Concentric Jet Flow

    Directory of Open Access Journals (Sweden)

    Elka Faizal

    2016-05-01

    Full Text Available Nozzle shape greatly influence turbulence between the fuel, air and formation of flow recirculation zone to produce a homogeneous mixing and get a near-perfect combustion. The recirculation zone is area that caused by flow rate breakdown, causing vortex and backflow around the end of nozzle. This backflow that hold up while lowering the flame so the flow rate of fuel and air mixture maintained lower or equal with flame speed. This study used variation of lip thickness of truncated nozzle 0, 4, 8, 12, and 16 mm.To obtain flame stability, fuel velocity and air velocity were variated. Thermocouples were used to measure flame temperature and its distribution. The results showed that stability of concentric jet diffusion flame flow increased with narrow lip thickness on a truncated nozzle. The wider stability area obtained in 4 mm lip thickness. In addition, temperature on diffusion flames concentric jet flow also more evenly distributed evenly with size of the nozzle lip thickness. The highest temperature and temperature distribution in the horizontal direction were occured in in the nozzle with lip thickness of 0 mm. A shadowgrapgh visualization was also used to identify phenomena of the nozzle exit flow.

  11. Spatial variability of soil CO2 emission in a sugarcane area characterized by secondary information

    Directory of Open Access Journals (Sweden)

    Daniel De Bortoli Teixeira

    2013-06-01

    Full Text Available Soil CO2 emission (FCO2 is governed by the inherent properties of the soil, such as bulk density (BD. Mapping of FCO2 allows the evaluation and identification of areas with different accumulation potential of carbon. However, FCO2 mapping over larger areas is not feasible due to the period required for evaluation. This study aimed to assess the quality of FCO2 spatial estimates using values of BD as secondary information. FCO2 and BD were evaluated on a regular sampling grid of 60 m × 60 m comprising 141 points, which was established on a sugarcane area. Four scenarios were defined according to the proportion of the number of sampling points of FCO2 to those of BD. For these scenarios, 67 (F67, 87 (F87, 107 (F107 and 127 (F127 FCO2 sampling points were used in addition to 127 BD sampling points used as supplementary information. The use of additional information from the BD provided an increase in the accuracy of the estimates only in the F107, F67 and F87 scenarios, respectively. The F87 scenario, with the approximate ratio between the FCO2 and BD of 1.00:1.50, presented the best relative improvement in the quality of estimates, thereby indicating that the BD should be sampled at a density 1.5 time greater than that applied for the FCO2. This procedure avoided problems related to the high temporal variability associated with FCO2, which enabled the mapping of this variable to be elaborated in large areas.

  12. High Pressure Water Stripping Using Multi-Orifice Nozzles

    Science.gov (United States)

    Hoppe, David

    1999-01-01

    The use of multi-orifice rotary nozzles greatly increases the speed and stripping effectiveness of high pressure water blasting systems, but also greatly increases the complexity of selecting and optimizing the operating parameters. The rotational speed of the nozzle must be coupled with its transverse velocity as it passes across the surface of the substrate being stripped. The radial and angular positions of each orifice must be included in the analysis of the nozzle configuration. Orifices at the outer edge of the nozzle head move at a faster rate than the orifices located near the center. The energy transmitted to the surface from the impact force of the water stream from an outer orifice is therefore spread over a larger area than energy from an inner orifice. Utilizing a larger diameter orifice in the outer radial positions increases the total energy transmitted from the outer orifice to compensate for the wider distribution of energy. The total flow rate from the combination of all orifices must be monitored and should be kept below the pump capacity while choosing orifice to insert in each position. The energy distribution from the orifice pattern is further complicated since the rotary path of all the orifices in the nozzle head pass through the center section. All orifices contribute to the stripping in the center of the path while only the outer most orifice contributes to the stripping at the edge of the nozzle. Additional orifices contribute to the stripping from the outer edge toward the center section. With all these parameters to configure and each parameter change affecting the others, a computer model was developed to track and coordinate these parameters. The computer simulation graphically indicates the cumulative affect from each parameter selected. The result from the proper choices in parameters is a well designed, highly efficient stripping system. A poorly chosen set of parameters will cause the nozzle to strip aggressively in some areas

  13. Through an Annular Turbine Nozzle

    Directory of Open Access Journals (Sweden)

    Rainer Kurz

    1995-01-01

    is located in the gas turbine. The experiments were performed using total pressure probes and wall static pressure taps. The pitch variation modifies the flow field both upstream and downstream of the nozzle, although the experiments show that the effect is localized to the immediate neighborhood of the involved blades. The effects on the wakes and on the inviscid flow are discussed separately. The mean velocities show a strong sensitivity to the changes of the pitch, which is due to a potential flow effect rather than a viscous effect.

  14. Axisymmetric nozzles with chamfered contraction

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav

    2017-01-01

    Roč. 263, August (2017), s. 147-158 ISSN 0924-4247 Institutional support: RVO:61388998 Keywords : nozzles * chamfering * invariant Subject RIV: BK - Fluid Dynamics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.499, year: 2016 http://ac.els-cdn.com/S0924424716310329/1-s2.0-S0924424716310329-main.pdf?_tid=f953dc4c-873c-11e7-b8d0-00000aacb35d&acdnat=1503408341_51527a384c272a3c4e8f43e6046d789d

  15. Urban mobility, socioeconomic and urban transport variables in metropolitan areas in three continents

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho da Costa, F.B. de; Nassi, C.D.

    2016-07-01

    Transportation is the soul of urban cities. Find sustainable ways to keep people moving in our cities is more important than ever. Historically, cities have developed in different ways. Each has its own personality and complexity. But in all cases, transport and mobility have played a key role in city life. Due to the relevance of mobility this article tries to establish the relationship between some variables. The method was developed by collecting, analyzing and comparing data on metropolitan regions in North America, South America, Europe and Oceania through a mathematical model. From each selected location the following data were gathered: population, area (km²), demographic density (inhab/km²), socio-economic aspects (annual GDP per capita), transport system (subway extension), number of trips per person per day and modal split (% non-motorized, % public transport and % private transport). In this study we analyze some variables that influence the number of trips per person per day. Understanding the associations between all the variables that influence the number of trips per person per day contributes the planners to determine whether changes are needed to improve in the transport system in the metropolitan region. (Author)

  16. Variability of zooplankton communities at Condor seamount and surrounding areas, Azores (NE Atlantic)

    Science.gov (United States)

    Carmo, Vanda; Santos, Mariana; Menezes, Gui M.; Loureiro, Clara M.; Lambardi, Paolo; Martins, Ana

    2013-12-01

    Seamounts are common topographic features around the Azores archipelago (NE Atlantic). Recently there has been increasing research effort devoted to the ecology of these ecosystems. In the Azores, the mesozooplankon is poorly studied, particularly in relation to these seafloor elevations. In this study, zooplankton communities in the Condor seamount area (Azores) were investigated during March, July and September 2010. Samples were taken during both day and night with a Bongo net of 200 µm mesh that towed obliquely within the first 100 m of the water column. Total abundance, biomass and chlorophyll a concentrations did not vary with sampling site or within the diel cycle but significant seasonal variation was observed. Moreover, zooplankton community composition showed the same strong seasonal pattern regardless of spatial or daily variability. Despite seasonal differences, the zooplankton community structure remained similar for the duration of this study. Seasonal variability better explained our results than mesoscale spatial variability. Spatial homogeneity is probably related with island proximity and local dynamics over Condor seamount. Zooplankton literature for the region is sparse, therefore a short review of the most important zooplankton studies from the Azores is also presented.

  17. Climate Variability and Industrial-Suburban Heat Environment in a Mediterranean Area

    Directory of Open Access Journals (Sweden)

    Giuseppina A. Giorgio

    2017-05-01

    Full Text Available The Urban Heat Island (UHI phenomenon prevalently concerns industrialized countries. It consists of a significant increase in temperatures, especially in industrialized and urbanized areas, in particular, during extreme warm periods like summer. This paper explores the climate variability of temperatures in two stations located in Matera city (Southern Italy, evaluating the increase in temperatures from 1988 to 2015. Moreover, the Corine Land Covers (1990–2000–2006–2012 were used in order to investigate the effect of land use on temperatures. The results obtained confirm the prevalence of UHI phenomena for industrialized areas, highlighting the proposal that the spreading of settlements may further drive these effects on the microclimate. In particular, the presence of industrial structures, even in rural areas, shows a clear increase in summer maximum temperatures. This does not occur in the period before 2000, probably due to the absence of the industrial settlement. On the contrary, from 2000 to 2015, changes are not relevant, but the maximum temperatures have always been higher than in the suburban area (station localized in green zone during daylight hours.

  18. GIS Based Distributed Runoff Predictions in Variable Source Area Watersheds Employing the SCS-Curve Number

    Science.gov (United States)

    Steenhuis, T. S.; Mendoza, G.; Lyon, S. W.; Gerard Marchant, P.; Walter, M. T.; Schneiderman, E.

    2003-04-01

    Because the traditional Soil Conservation Service Curve Number (SCS-CN) approach continues to be ubiquitously used in GIS-BASED water quality models, new application methods are needed that are consistent with variable source area (VSA) hydrological processes in the landscape. We developed within an integrated GIS modeling environment a distributed approach for applying the traditional SCS-CN equation to watersheds where VSA hydrology is a dominant process. Spatial representation of hydrologic processes is important for watershed planning because restricting potentially polluting activities from runoff source areas is fundamental to controlling non-point source pollution. The methodology presented here uses the traditional SCS-CN method to predict runoff volume and spatial extent of saturated areas and uses a topographic index to distribute runoff source areas through watersheds. The resulting distributed CN-VSA method was incorporated in an existing GWLF water quality model and applied to sub-watersheds of the Delaware basin in the Catskill Mountains region of New York State. We found that the distributed CN-VSA approach provided a physically-based method that gives realistic results for watersheds with VSA hydrology.

  19. Progress with variable cycle engines

    Science.gov (United States)

    Westmoreland, J. S.

    1980-01-01

    The evaluation of components of an advanced propulsion system for a future supersonic cruise vehicle is discussed. These components, a high performance duct burner for thrust augmentation and a low jet noise coannular exhaust nozzle, are part of the variable stream control engine. An experimental test program involving both isolated component and complete engine tests was conducted for the high performance, low emissions duct burner with excellent results. Nozzle model tests were completed which substantiate the inherent jet noise benefit associated with the unique velocity profile possible of a coannular exhaust nozzle system on a variable stream control engine. Additional nozzle model performance tests have established high thrust efficiency levels at takeoff and supersonic cruise for this nozzle system. Large scale testing of these two critical components is conducted using an F100 engine as the testbed for simulating the variable stream control engine.

  20. Pengaruh Jarak dan Posisi Nozzle terhadap Daya Turbin Pelton

    OpenAIRE

    Kurniawan, Yani; Pane, Erlanda Augupta; Ismail, Ismail

    2017-01-01

    Pelton Turbine is a turbine which use nozzle as officers the direction of a stream water in order to move around of blade turbine. The rotating of turbine blade efected by some parameters such as the distance of the nozzle, position of nozzle, diameter of nozzle, number of nozzle, and the geometry shape of the blade turbine. An experimental study to analyze the affect of distance and position nozzle to Pelton Turbine of performance. The research method used experiment parameter was position o...

  1. Pengaruh Jarak dan Posisi Nozzle Terhadap Daya Turbin Pelton

    OpenAIRE

    Yani Kurniawan; Erlanda Augupta Pane; Ismail

    2017-01-01

    Pelton Turbine is a turbine which use nozzle as officers the direction of a stream water in order to move around of blade turbine. The rotating of turbine blade efected by some parameters such as the distance of the nozzle, position of nozzle, diameter of nozzle, number of nozzle, and the geometry shape of the blade turbine. An experimental study to analyze the affect of distance and position nozzle to Pelton Turbine of performance. The research method used experiment parameter was position o...

  2. Palo Verde Unit 3 BMI nozzle modification

    International Nuclear Information System (INIS)

    Waskey, D.

    2015-01-01

    The 61 BMI (Bottom Mount Instrumentation) nozzles of the unit 3 of the Palo Verde plant have been examined through ASME Code Case N722. The nozzle 3 was the only one with leakage noted. The ultrasound testing results are characteristic of PWSCC (Primary Water Stress Corrosion Cracking). The initiation likely occurred at a weld defect which was exposed to the primary water environment resulting in PWSCC. All other nozzles (60) showed no unacceptable indications. Concerning nozzle 3 one crack in J-groove weld connected large defect to primary water. An environmental model has been used to simulate and optimize the repair. The AREVA crew was on site 18 days after contract award and the job was completed in 12 days, 30 hours ahead of baseline schedule. This series of slides describes the examination of the BMI nozzles, the repair steps, and alternative design concepts

  3. Diurnal and seasonal variability of outdoor radon concentration in the area of the NRPI Prague.

    Science.gov (United States)

    Jilek, K; Slezákova, M; Thomas, J

    2014-07-01

    In autumn 2010, an outdoor measuring station for measurement of atmospheric radon, gamma equivalent dose rate in the range of 100 nSv h(-1)-1 Sv h(-1) and proper meteorological parameters such as thermal air gradient, relative air humidity, wind speed and direction and solar radiation intensity was built in the area of the National Radiation Protection Institute vvi. The station was designed to be independent of an electrical network and enables on-line wireless transfer of all data. After introduction of the station, illustrations of its measurement properties and the results of measured diurnal and seasonal variability of atmospheric radon, based on annual continuous measurement using a high-volume scintillation cell at a height of 2.5 m above the ground, are presented. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Characterizing spatial variability of air pollution from vehicle traffic around the Houston Ship Channel area

    Science.gov (United States)

    Zhang, Xueying; Craft, Elena; Zhang, Kai

    2017-07-01

    Mobile emissions are a major source of urban air pollution and have been associated with a variety of adverse health outcomes. The Houston Ship Channel area is the home of a large number of diesel-powered vehicles emitting fine particulate matter (PM2.5; ≤2.5 μm in aerodynamic diameter) and nitrogen oxides (NOx). However, the spatial variability of traffic-related air pollutants in the Houston Ship Channel area has rarely been investigated. The objective of this study is to characterize spatial variability of PM2.5 and NOx concentrations attributable to on-road traffic in the Houston Ship Channel area in the year of 2011. We extracted the road network from the Texas Department of Transportation Road Inventory, and calculated emission rates using the Motor Vehicle Emission Simulator version 2014a (MOVES2014a). These parameters and preprocessed meteorological parameters were entered into a Research LINE-source Dispersion Model (RLINE) to conduct a simulation. Receptors were placed at 50 m resolution within 300 m to major roads and at 150 m resolution in the rest of the area. Our findings include that traffic-related PM2.5 were mainly emitted from trucks, while traffic-related NOx were emitted from both trucks and cars. The traffic contributed 0.90 μg/m3 PM2.5 and 29.23 μg/m3 NOx to the annual average mass concentrations of on-road air pollution, and the concentrations of the two pollutants decreased by nearly 40% within 500 m distance to major roads. The pollution level of traffic-related PM2.5 and NOx was higher in winter than those in the other three seasons. The Houston Ship Channel has earlier morning peak hours and relative late afternoon hours, which indicates the influence of goods movement from port activity. The varied near-road gradients illustrate that proximities to major roads are not an accurate surrogate of traffic-related air pollution.

  5. Variable Scheduling to Mitigate Channel Losses in Energy-Efficient Body Area Networks

    Directory of Open Access Journals (Sweden)

    Lavy Libman

    2012-11-01

    Full Text Available We consider a typical body area network (BAN setting in which sensor nodes send data to a common hub regularly on a TDMA basis, as defined by the emerging IEEE 802.15.6 BAN standard. To reduce transmission losses caused by the highly dynamic nature of the wireless channel around the human body, we explore variable TDMA scheduling techniques that allow the order of transmissions within each TDMA round to be decided on the fly, rather than being fixed in advance. Using a simple Markov model of the wireless links, we devise a number of scheduling algorithms that can be performed by the hub, which aim to maximize the expected number of successful transmissions in a TDMA round, and thereby significantly reduce transmission losses as compared with a static TDMA schedule. Importantly, these algorithms do not require a priori knowledge of the statistical properties of the wireless channels, and the reliability improvement is achieved entirely via shuffling the order of transmissions among devices, and does not involve any additional energy consumption (e.g., retransmissions. We evaluate these algorithms directly on an experimental set of traces obtained from devices strapped to human subjects performing regular daily activities, and confirm that the benefits of the proposed variable scheduling algorithms extend to this practical setup as well.

  6. Vanishing Viscosity Approach to the Compressible Euler Equations for Transonic Nozzle and Spherically Symmetric Flows

    Science.gov (United States)

    Chen, Gui-Qiang G.; Schrecker, Matthew R. I.

    2018-04-01

    We are concerned with globally defined entropy solutions to the Euler equations for compressible fluid flows in transonic nozzles with general cross-sectional areas. Such nozzles include the de Laval nozzles and other more general nozzles whose cross-sectional area functions are allowed at the nozzle ends to be either zero (closed ends) or infinity (unbounded ends). To achieve this, in this paper, we develop a vanishing viscosity method to construct globally defined approximate solutions and then establish essential uniform estimates in weighted L p norms for the whole range of physical adiabatic exponents γ\\in (1, ∞) , so that the viscosity approximate solutions satisfy the general L p compensated compactness framework. The viscosity method is designed to incorporate artificial viscosity terms with the natural Dirichlet boundary conditions to ensure the uniform estimates. Then such estimates lead to both the convergence of the approximate solutions and the existence theory of globally defined finite-energy entropy solutions to the Euler equations for transonic flows that may have different end-states in the class of nozzles with general cross-sectional areas for all γ\\in (1, ∞) . The approach and techniques developed here apply to other problems with similar difficulties. In particular, we successfully apply them to construct globally defined spherically symmetric entropy solutions to the Euler equations for all γ\\in (1, ∞).

  7. Step-by-step variability of swing phase trajectory area during steady state walking at a range of speeds

    Science.gov (United States)

    Hurt, Christopher P.; Brown, David A.

    2018-01-01

    Background Step kinematic variability has been characterized during gait using spatial and temporal kinematic characteristics. However, people can adopt different trajectory paths both between individuals and even within individuals at different speeds. Single point measures such as minimum toe clearance (MTC) and step length (SL) do not necessarily account for the multiple paths that the foot may take during the swing phase to reach the same foot fall endpoint. The purpose of this study was to test a step-by-step foot trajectory area (SBS-FTA) variability measure that is able to characterize sagittal plane foot trajectories of varying areas, and compare this measure against MTC and SL variability at different speeds. We hypothesize that the SBS-FTA variability would demonstrate increased variability with speed. Second, we hypothesize that SBS-FTA would have a stronger curvilinear fit compared with the CV and SD of SL and MTC. Third, we hypothesize SBS-FTA would be more responsive to change in the foot trajectory at a given speed compared to SL and MTC. Fourth, SBS-FTA variability would not strongly co-vary with SL and MTC variability measures since it represents a different construct related to foot trajectory area variability. Methods We studied 15 nonimpaired individuals during walking at progressively faster speeds. We calculated SL, MTC, and SBS-FTA area. Results SBS-FTA variability increased with speed, had a stronger curvilinear fit compared with the CV and SD of SL and MTC, was more responsive at a given speed, and did not strongly co-vary with SL and MTC variability measures. Conclusion SBS foot trajectory area variability was sensitive to change with faster speeds, captured a relationship that the majority of the other measures did not demonstrate, and did not co-vary strongly with other measures that are also components of the trajectory. PMID:29370202

  8. Spatial and temporal variability of rainfall and their effects on hydrological response in urban areas – a review

    OpenAIRE

    E. Cristiano; M.-C. ten Veldhuis; N. van de Giesen

    2017-01-01

    In urban areas, hydrological processes are characterized by high variability in space and time, making them sensitive to small-scale temporal and spatial rainfall variability. In the last decades new instruments, techniques, and methods have been developed to capture rainfall and hydrological processes at high resolution. Weather radars have been introduced to estimate high spatial and temporal rainfall variability. At the same time, new models have been proposed to reproduce hydrological res...

  9. The effects of finite rate chemical processes on high enthalpy nozzle performance - A comparison between SPARK and SEAGULL

    Science.gov (United States)

    Carpenter, M. H.

    1988-01-01

    The generalized chemistry version of the computer code SPARK is extended to include two higher-order numerical schemes, yielding fourth-order spatial accuracy for the inviscid terms. The new and old formulations are used to study the influences of finite rate chemical processes on nozzle performance. A determination is made of the computationally optimum reaction scheme for use in high-enthalpy nozzles. Finite rate calculations are compared with the frozen and equilibrium limits to assess the validity of each formulation. In addition, the finite rate SPARK results are compared with the constant ratio of specific heats (gamma) SEAGULL code, to determine its accuracy in variable gamma flow situations. Finally, the higher-order SPARK code is used to calculate nozzle flows having species stratification. Flame quenching occurs at low nozzle pressures, while for high pressures, significant burning continues in the nozzle.

  10. Spatial and temporal variability of rainfall and their effects on hydrological response in urban areas - A review

    NARCIS (Netherlands)

    Cristiano, E.; ten Veldhuis, J.A.E.; van de Giesen, N.C.

    2017-01-01

    In urban areas, hydrological processes are characterized by high variability in space and time, making them sensitive to small-scale temporal and spatial rainfall variability. In the last decades new instruments, techniques, and methods have been developed to capture rainfall and hydrological

  11. Supersonic flaw detection device for nozzle

    International Nuclear Information System (INIS)

    Hata, Moriki.

    1996-01-01

    In a supersonic flaw detection device to be attached to a body surface of a reactor pressure vessel for automatically detecting flaws of a welded portion of a horizontally connected nozzle by using supersonic waves, a running vehicle automatically running along a circumferential direction of the nozzle comprises a supersonic flaw detection means for detecting flaws of the welded portion of the nozzle by using supersonic waves, and an inclination angle sensor for detecting the inclination angle of the running vehicle relative to the central axis of the nozzle. The running distance of the vehicle running along the circumference of the nozzle, namely, the position of the running vehicle from a reference point of the nozzle can be detected accurately by dividing the distance around the nozzle by the inclination angle detected by the inclination angle sensor. Accordingly, disadvantages in the prior art, for example, that the detected values obtained by using an encoder are changed by slipping or idle running of the magnet wheels are eliminated, and accurate flaw detection can be conducted. In addition, an operation of visually adjusting the reference point for the device can be eliminated. An operator's exposure dose can be reduced. (N.H.)

  12. Spatial and temporal variability of rainfall and their effects on hydrological response in urban areas - a review

    Science.gov (United States)

    Cristiano, Elena; ten Veldhuis, Marie-claire; van de Giesen, Nick

    2017-07-01

    In urban areas, hydrological processes are characterized by high variability in space and time, making them sensitive to small-scale temporal and spatial rainfall variability. In the last decades new instruments, techniques, and methods have been developed to capture rainfall and hydrological processes at high resolution. Weather radars have been introduced to estimate high spatial and temporal rainfall variability. At the same time, new models have been proposed to reproduce hydrological response, based on small-scale representation of urban catchment spatial variability. Despite these efforts, interactions between rainfall variability, catchment heterogeneity, and hydrological response remain poorly understood. This paper presents a review of our current understanding of hydrological processes in urban environments as reported in the literature, focusing on their spatial and temporal variability aspects. We review recent findings on the effects of rainfall variability on hydrological response and identify gaps where knowledge needs to be further developed to improve our understanding of and capability to predict urban hydrological response.

  13. Effect of water injection and off scheduling of variable inlet guide vanes, gas generator speed and power turbine nozzle angle on the performance of an automotive gas turbine engine

    Science.gov (United States)

    Warren, E. L.

    1980-01-01

    The Chrysler/ERDA baseline automotive gas turbine engine was used to experimentally determine the power augmentation and emissions reductions achieved by the effect of variable compressor and power engine geometry, water injection downstream of the compressor, and increases in gas generator speed. Results were dependent on the mode of variable geometry utilization. Over 20 percent increase in power was accompanied by over 5 percent reduction in SFC. A fuel economy improvement of at least 6 percent was estimated for a vehicle with a 75 kW (100 hp) engine which could be augmented to 89 kW (120 hp) relative to an 89 Kw (120 hp) unaugmented engine.

  14. Ambipolar ion acceleration in an expanding magnetic nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Longmier, Benjamin W; Carter, Mark D; Cassady, Leonard D; Chancery, William J; Diaz, Franklin R Chang; Glover, Tim W; Ilin, Andrew V; McCaskill, Greg E; Olsen, Chris S; Squire, Jared P [Ad Astra Rocket Company, 141 W. Bay Area Blvd, Webster, TX (United States); Bering, Edgar A III [Department of Physics and Department of Electrical and Computer Engineering, University of Houston, 617 Science and Research Building 1, Houston, TX (United States); Hershkowitz, Noah [Department of Engineering Physics, University of Wisconsin, 1500 Engineering Dr., Madison, WI (United States)

    2011-02-15

    The helicon plasma stage in the Variable Specific Impulse Magnetoplasma Rocket (VASIMR (registered)) VX-200i device was used to characterize an axial plasma potential profile within an expanding magnetic nozzle region of the laboratory based device. The ion acceleration mechanism is identified as an ambipolar electric field produced by an electron pressure gradient, resulting in a local axial ion speed of Mach 4 downstream of the magnetic nozzle. A 20 eV argon ion kinetic energy was measured in the helicon source, which had a peak magnetic field strength of 0.17 T. The helicon plasma source was operated with 25 mg s{sup -1} argon propellant and 30 kW of RF power. The maximum measured values of plasma density and electron temperature within the exhaust plume were 1 x 10{sup 20} m{sup -3} and 9 eV, respectively. The measured plasma density is nearly an order of magnitude larger than previously reported steady-state helicon plasma sources. The exhaust plume also exhibits a 95% to 100% ionization fraction. The size scale and spatial location of the plasma potential structure in the expanding magnetic nozzle region appear to follow the size scale and spatial location of the expanding magnetic field. The thickness of the potential structure was found to be 10{sup 4} to 10{sup 5} {lambda}{sub De} depending on the local electron temperature in the magnetic nozzle, many orders of magnitude larger than typical laboratory double layer structures. The background plasma density and neutral argon pressure were 10{sup 15} m{sup -3} and 2 x 10{sup -5} Torr, respectively, in a 150 m{sup 3} vacuum chamber during operation of the helicon plasma source. The agreement between the measured plasma potential and plasma potential that was calculated from an ambipolar ion acceleration analysis over the bulk of the axial distance where the potential drop was located is a strong confirmation of the ambipolar acceleration process.

  15. Land Use Induced Hydroclimatic Variability Over Large Deforested Areas in Southern Amazon Rainforest

    Science.gov (United States)

    Khanna, J.; Medvigy, D.

    2017-12-01

    Contemporary Amazonian deforestation, which occurs at scales of a few hundreds of kilometers, has been found to induce systematic changes in the regional dry season precipitation. The replacement of rough forest with smooth pasture induces a low level atmospheric convergence and uplift in the downwind and divergence and subsidence in the upwind deforested areas. The resulting precipitation change is about ±30% of the deforested area mean in the two regions respectively. Compared with the increase in non-precipitating cloudiness triggered by small scale clearings prevalent in the early phases of deforestation, this `dynamical mesoscale circulation' can have regional ecological impacts by altering precipitation seasonality and in turn ecosystem dynamics. However, the seasonality and variability of this phenomenon hasn't been studied. Using observations and numerical simulations this study investigates the relationships between the dynamical mechanism and the local- and continental-scale atmospheric conditions to understand the physical controls on this phenomenon on the inter-annual, inter-seasonal and daily time scales. We find that the strength of the dynamical mechanism is controlled mostly by regional scale thermal and dynamical conditions of the boundary layer and not the continental and global scale atmospheric state. The lifting condensation level (thermodynamic control) and wind speed (dynamic control) within the boundary layer have the largest and positive correlations with the dipole strength, which is true although not always significant across time scales. Due to this dependence it is found to be strongest during parts of the year when the atmosphere is relatively stable. Hence, overall this phenomenon is found to be the prevalent convective triggering mechanism during the dry and parts of transition seasons (especially spring), significantly affecting the hydroclimate during this period.

  16. Spatially uniform but temporally variable bacterioplankton in a semi-enclosed coastal area.

    Science.gov (United States)

    Meziti, Alexandra; Kormas, Konstantinos A; Moustaka-Gouni, Maria; Karayanni, Hera

    2015-07-01

    Studies focusing on the temporal and spatial dynamics of bacterioplankton communities within littoral areas undergoing direct influences from the coast are quite limited. In addition, they are more complicated to resolve compared to communities in the open ocean. In order to elucidate the effects of spatial vs. temporal variability on bacterial communities in a highly land-influenced semi-enclosed gulf, surface bacterioplankton communities from five coastal sites in Igoumenitsa Gulf (Ionian Sea, Greece) were analyzed over a nine-month period using 16S rDNA 454-pyrosequencing. Temporal differences were more pronounced than spatial ones, with lower diversity indices observed during the summer months. During winter and early spring, bacterial communities were dominated by SAR11 representatives, while this pattern changed in May when they were abruptly replaced by members of Flavobacteriales, Pseudomonadales, and Alteromonadales. Additionally, correlation analysis showed high negative correlations between the presence of SAR11 OTUs in relation to temperature and sunlight that might have driven, directly or indirectly, the disappearance of these OTUs in the summer months. The dominance of SAR11 during the winter months further supported the global distribution of the clade, not only in the open-sea, but also in coastal systems. This study revealed that specific bacteria exhibited distinct succession patterns in an anthropogenic-impacted coastal system. The major bacterioplankton component was represented by commonly found marine bacteria exhibiting seasonal dynamics, while freshwater and terrestrial-related phylotypes were absent. Copyright © 2015 Elsevier GmbH. All rights reserved.

  17. Validation of the USGS Landsat Burned Area Essential Climate Variable (BAECV) across the conterminous United States

    Science.gov (United States)

    Vanderhoof, Melanie; Fairaux, Nicole; Beal, Yen-Ju G.; Hawbaker, Todd J.

    2017-01-01

    The Landsat Burned Area Essential Climate Variable (BAECV), developed by the U.S. Geological Survey (USGS), capitalizes on the long temporal availability of Landsat imagery to identify burned areas across the conterminous United States (CONUS) (1984–2015). Adequate validation of such products is critical for their proper usage and interpretation. Validation of coarse-resolution products often relies on independent data derived from moderate-resolution sensors (e.g., Landsat). Validation of Landsat products, in turn, is challenging because there is no corresponding source of high-resolution, multispectral imagery that has been systematically collected in space and time over the entire temporal extent of the Landsat archive. Because of this, comparison between high-resolution images and Landsat science products can help increase user's confidence in the Landsat science products, but may not, alone, be adequate. In this paper, we demonstrate an approach to systematically validate the Landsat-derived BAECV product. Burned area extent was mapped for Landsat image pairs using a manually trained semi-automated algorithm that was manually edited across 28 path/rows and five different years (1988, 1993, 1998, 2003, 2008). Three datasets were independently developed by three analysts and the datasets were integrated on a pixel by pixel basis in which at least one to all three analysts were required to agree a pixel was burned. We found that errors within our Landsat reference dataset could be minimized by using the rendition of the dataset in which pixels were mapped as burned if at least two of the three analysts agreed. BAECV errors of omission and commission for the detection of burned pixels averaged 42% and 33%, respectively for CONUS across all five validation years. Errors of omission and commission were lowest across the western CONUS, for example in the shrub and scrublands of the Arid West (31% and 24%, respectively), and highest in the grasslands and

  18. Integrated Composite Rocket Nozzle Extension, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop and demonstrate an Integrated Composite Rocket Nozzle Extension (ICRNE) for use in rocket thrust chambers. The ICRNE will utilize an...

  19. Aerospike Nozzle for Rotating Detonation Engine Application

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal presents a graduate MS research thesis on improving the efficiency of rotating detonation engines by using aerospike nozzle technologies. A rotating...

  20. Transient Three-Dimensional Side Load Analysis of a Film Cooled Nozzle

    Science.gov (United States)

    Wang, Ten-See; Guidos, Mike

    2008-01-01

    Transient three-dimensional numerical investigations on the side load physics for an engine encompassing a film cooled nozzle extension and a regeneratively cooled thrust chamber, were performed. The objectives of this study are to identify the three-dimensional side load physics and to compute the associated aerodynamic side load using an anchored computational methodology. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and a transient inlet history based on an engine system simulation. Ultimately, the computational results will be provided to the nozzle designers for estimating of effect of the peak side load on the nozzle structure. Computations simulating engine startup at ambient pressures corresponding to sea level and three high altitudes were performed. In addition, computations for both engine startup and shutdown transients were also performed for a stub nozzle, operating at sea level. For engine with the full nozzle extension, computational result shows starting up at sea level, the peak side load occurs when the lambda shock steps into the turbine exhaust flow, while the side load caused by the transition from free-shock separation to restricted-shock separation comes at second; and the side loads decreasing rapidly and progressively as the ambient pressure decreases. For the stub nozzle operating at sea level, the computed side loads during both startup and shutdown becomes very small due to the much reduced flow area.

  1. Jet Noise Scaling in Dual Stream Nozzles

    Science.gov (United States)

    Khavaran, Abbas; Bridges, James

    2010-01-01

    Power spectral laws in dual stream jets are studied by considering such flows a superposition of appropriate single-stream coaxial jets. Noise generation in each mixing region is modeled using spectral power laws developed earlier for single stream jets as a function of jet temperature and observer angle. Similarity arguments indicate that jet noise in dual stream nozzles may be considered as a composite of four single stream jets representing primary/secondary, secondary/ambient, transition, and fully mixed zones. Frequency filter are designed to highlight spectral contribution from each jet. Predictions are provided at an area ratio of 2.0--bypass ratio from 0.80 to 3.40, and are compared with measurements within a wide range of velocity and temperature ratios. These models suggest that the low frequency noise in unheated jets is dominated by the fully mixed region at all velocity ratios, while the high frequency noise is dominated by the secondary when the velocity ratio is larger than 0.80. Transition and fully mixed jets equally dominate the low frequency noise in heated jets. At velocity ratios less than 0.50, the high frequency noise from primary/bypass becomes a significant contributing factor similar to that in the secondary/ambient jet.

  2. Implications of Wide-Area Geographic Diversity for Short- Term Variability of Solar Power

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Andrew; Wiser, Ryan

    2010-08-23

    Worldwide interest in the deployment of photovoltaic generation (PV) is rapidly increasing. Operating experience with large PV plants, however, demonstrates that large, rapid changes in the output of PV plants are possible. Early studies of PV grid impacts suggested that short-term variability could be a potential limiting factor in deploying PV. Many of these early studies, however, lacked high-quality data from multiple sites to assess the costs and impacts of increasing PV penetration. As is well known for wind, accounting for the potential for geographic diversity can significantly reduce the magnitude of extreme changes in aggregated PV output, the resources required to accommodate that variability, and the potential costs of managing variability. We use measured 1-min solar insolation for 23 time-synchronized sites in the Southern Great Plains network of the Atmospheric Radiation Measurement program and wind speed data from 10 sites in the same network to characterize the variability of PV with different degrees of geographic diversity and to compare the variability of PV to the variability of similarly sited wind. The relative aggregate variability of PV plants sited in a dense 10 x 10 array with 20 km spacing is six times less than the variability of a single site for variability on time scales less than 15-min. We find in our analysis of wind and PV plants similarly sited in a 5 x 5 grid with 50 km spacing that the variability of PV is only slightly more than the variability of wind on time scales of 5-15 min. Over shorter and longer time scales the level of variability is nearly identical. Finally, we use a simple approximation method to estimate the cost of carrying additional reserves to manage sub-hourly variability. We conclude that the costs of managing the short-term variability of PV are dramatically reduced by geographic diversity and are not substantially different from the costs for managing the short-term variability of similarly sited wind in

  3. Single nozzle spray drift measurements of drift reducing nozzles at two forward speeds

    NARCIS (Netherlands)

    Stallinga, H.; Zande, van de J.C.; Michielsen, J.G.P.; Velde, van P.

    2016-01-01

    In 2011‒2012 single nozzle field experiments were carried out to determine the effect of different flat fan spray nozzles of the spray drift reduction classes 50, 75, 90 and 95% on spray drift at two different forward speeds (7.2 km h-1 and 14.4 km h-1). Experiments were performed with a single

  4. Computational study of performance characteristics for truncated conical aerospike nozzles

    Science.gov (United States)

    Nair, Prasanth P.; Suryan, Abhilash; Kim, Heuy Dong

    2017-12-01

    Aerospike nozzles are advanced rocket nozzles that can maintain its aerodynamic efficiency over a wide range of altitudes. It belongs to class of altitude compensating nozzles. A vehicle with an aerospike nozzle uses less fuel at low altitudes due to its altitude adaptability, where most missions have the greatest need for thrust. Aerospike nozzles are better suited to Single Stage to Orbit (SSTO) missions compared to conventional nozzles. In the current study, the flow through 20% and 40% aerospike nozzle is analyzed in detail using computational fluid dynamics technique. Steady state analysis with implicit formulation is carried out. Reynolds averaged Navier-Stokes equations are solved with the Spalart-Allmaras turbulence model. The results are compared with experimental results from previous work. The transition from open wake to closed wake happens in lower Nozzle Pressure Ratio for 20% as compared to 40% aerospike nozzle.

  5. The Use of Woodland Products to Cope with Climate Variability in Communal Areas in Zimbabwe

    Directory of Open Access Journals (Sweden)

    Lotte S. Woittiez

    2013-12-01

    Full Text Available Common lands provide smallholder farmers in Africa with firewood, timber, and feed for livestock, and they are used to complement human diets through the collection of edible nontimber forest products (NTFPs. Farmers have developed coping mechanisms, which they deploy at times of climatic shocks. We aimed to analyze the importance of NTFPs in times of drought and to identify options that could increase the capacity to adapt to climate change. We used participatory techniques, livelihood analysis, observations, and measurements to quantify the use of NTFPs. Communities recognized NTFPs as a mechanism to cope with crop failure. We estimated that indigenous fruits contributed to approximately 20% of the energy intake of wealthier farmers and to approximately 40% of the energy intake of poor farmers in years of inadequate rainfall. Farmers needed to invest a considerable share of their time to collect wild fruits from deforested areas. They recognized that the effectiveness of NTFPs as an adaptation option had become threatened by severe deforestation and by illegal harvesting of fruits by urban traders. Farmers indicated the need to plan future land use to (1 intensify crop production, (2 cultivate trees for firewood, (3 keep orchards of indigenous fruit trees, and (4 improve the quality of grazing lands. Farmers were willing to cultivate trees and to organize communal conservation of indigenous fruits trees. Through participatory exercises, farmers elaborated maps, which were used during land use discussions. The process led to prioritization of pressing land use problems and identification of the support needed: fast-growing trees for firewood, inputs for crop production, knowledge on the cultivation of indigenous fruit trees, and clear regulations and compliance with rules for extraction of NTFPs. Important issues that remain to be addressed are best practices for regeneration and conservation, access rules and implementation, and the

  6. A new general dynamic model predicting radionuclide concentrations and fluxes in coastal areas from readily accessible driving variables

    International Nuclear Information System (INIS)

    Haakanson, Lars

    2004-01-01

    This paper presents a general, process-based dynamic model for coastal areas for radionuclides (metals, organics and nutrients) from both single pulse fallout and continuous deposition. The model gives radionuclide concentrations in water (total, dissolved and particulate phases and concentrations in sediments and fish) for entire defined coastal areas. The model gives monthly variations. It accounts for inflow from tributaries, direct fallout to the coastal area, internal fluxes (sedimentation, resuspension, diffusion, burial, mixing and biouptake and retention in fish) and fluxes to and from the sea outside the defined coastal area and/or adjacent coastal areas. The fluxes of water and substances between the sea and the coastal area are differentiated into three categories of coast types: (i) areas where the water exchange is regulated by tidal effects; (ii) open coastal areas where the water exchange is regulated by coastal currents; and (iii) semi-enclosed archipelago coasts. The coastal model gives the fluxes to and from the following four abiotic compartments: surface water, deep water, ET areas (i.e., areas where fine sediment erosion and transport processes dominate the bottom dynamic conditions and resuspension appears) and A-areas (i.e., areas of continuous fine sediment accumulation). Criteria to define the boundaries for the given coastal area towards the sea, and to define whether a coastal area is open or closed are given in operational terms. The model is simple to apply since all driving variables may be readily accessed from maps and standard monitoring programs. The driving variables are: latitude, catchment area, mean annual precipitation, fallout and month of fallout and parameters expressing coastal size and form as determined from, e.g., digitized bathymetric maps using a GIS program. Selected results: the predictions of radionuclide concentrations in water and fish largely depend on two factors, the concentration in the sea outside the given

  7. Pollution influence in the variability of the lichen Lecanora varia (Ehrh) ach in the area of Bratislava

    Energy Technology Data Exchange (ETDEWEB)

    Pisut, I; Jelinkova, E

    1973-01-01

    The lichen Lecanora varia was transplanted from nonpolluted areas to polluted areas in Bratislava. The morphology of the organisms changed; soredia and apothecia with a soredious margin were formed. New young ascocarp with a paler colored discus and a margin were common. The transformation is conditioned by the degree of air pollution exposure. The rate is variable, and depends considerably on macroclimatic circumstances (mainly on the quantity of precipitation in winter). 10 references, 3 figures, 5 tables.

  8. Thermal infrared imagery as a tool for analysing the variability of surface saturated areas at various temporal and spatial scales

    Science.gov (United States)

    Glaser, Barbara; Antonelli, Marta; Pfister, Laurent; Klaus, Julian

    2017-04-01

    Surface saturated areas are important for the on- and offset of hydrological connectivity within the hillslope-riparian-stream continuum. This is reflected in concepts such as variable contributing areas or critical source areas. However, we still lack a standardized method for areal mapping of surface saturation and for observing its spatiotemporal variability. Proof-of-concept studies in recent years have shown the potential of thermal infrared (TIR) imagery to record surface saturation dynamics at various temporal and spatial scales. Thermal infrared imagery is thus a promising alternative to conventional approaches, such as the squishy boot method or the mapping of vegetation. In this study we use TIR images to investigate the variability of surface saturated areas at different temporal and spatial scales in the forested Weierbach catchment (0.45 km2) in western Luxembourg. We took TIR images of the riparian zone with a hand-held FLIR infrared camera at fortnightly intervals over 18 months at nine different locations distributed over the catchment. Not all of the acquired images were suitable for a derivation of the surface saturated areas, as various factors influence the usability of the TIR images (e.g. temperature contrasts, shadows, fog). Nonetheless, we obtained a large number of usable images that provided a good insight into the dynamic behaviour of surface saturated areas at different scales. The images revealed how diverse the evolution of surface saturated areas can be throughout the hydrologic year. For some locations with similar morphology or topography we identified diverging saturation dynamics, while other locations with different morphology / topography showed more similar behaviour. Moreover, we were able to assess the variability of the dynamics of expansion / contraction of saturated areas within the single locations, which can help to better understand the mechanisms behind surface saturation development.

  9. Computational Fluid Dynamic (CFD) analysis of axisymmetric plume and base flow of film/dump cooled rocket nozzle

    Science.gov (United States)

    Tucker, P. K.; Warsi, S. A.

    1993-01-01

    Film/dump cooling a rocket nozzle with fuel rich gas, as in the National Launch System (NLS) Space Transportation Main Engine (STME), adds potential complexities for integrating the engine with the vehicle. The chief concern is that once the film coolant is exhausted from the nozzle, conditions may exist during flight for the fuel-rich film gases to be recirculated to the vehicle base region. The result could be significantly higher base temperatures than would be expected from a regeneratively cooled nozzle. CFD analyses were conduced to augment classical scaling techniques for vehicle base environments. The FDNS code with finite rate chemistry was used to simulate a single, axisymmetric STME plume and the NLS base area. Parallel calculations were made of the Saturn V S-1 C/F1 plume base area flows. The objective was to characterize the plume/freestream shear layer for both vehicles as inputs for scaling the S-C/F1 flight data to NLS/STME conditions. The code was validated on high speed flows with relevant physics. This paper contains the calculations for the NLS/STME plume for the baseline nozzle and a modified nozzle. The modified nozzle was intended to reduce the fuel available for recirculation to the vehicle base region. Plumes for both nozzles were calculated at 10kFT and 50kFT.

  10. Diurnal, synoptic and seasonal variability of atmospheric CO2 in the Paris megacity area

    Science.gov (United States)

    Xueref-Remy, Irène; Dieudonné, Elsa; Vuillemin, Cyrille; Lopez, Morgan; Lac, Christine; Schmidt, Martina; Delmotte, Marc; Chevallier, Frédéric; Ravetta, François; Perrussel, Olivier; Ciais, Philippe; Bréon, François-Marie; Broquet, Grégoire; Ramonet, Michel; Spain, T. Gerard; Ampe, Christophe

    2018-03-01

    Most of the global fossil fuel CO2 emissions arise from urbanized and industrialized areas. Bottom-up inventories quantify them but with large uncertainties. In 2010-2011, the first atmospheric in situ CO2 measurement network for Paris, the capital of France, began operating with the aim of monitoring the regional atmospheric impact of the emissions coming from this megacity. Five stations sampled air along a northeast-southwest axis that corresponds to the direction of the dominant winds. Two stations are classified as rural (Traînou - TRN; Montgé-en-Goële - MON), two are peri-urban (Gonesse - GON; Gif-sur-Yvette - GIF) and one is urban (EIF, located on top of the Eiffel Tower). In this study, we analyze the diurnal, synoptic and seasonal variability of the in situ CO2 measurements over nearly 1 year (8 August 2010-13 July 2011). We compare these datasets with remote CO2 measurements made at Mace Head (MHD) on the Atlantic coast of Ireland and support our analysis with atmospheric boundary layer height (ABLH) observations made in the center of Paris and with both modeled and observed meteorological fields. The average hourly CO2 diurnal cycles observed at the regional stations are mostly driven by the CO2 biospheric cycle, the ABLH cycle and the proximity to urban CO2 emissions. Differences of several µmol mol-1 (ppm) can be observed from one regional site to the other. The more the site is surrounded by urban sources (mostly residential and commercial heating, and traffic), the more the CO2 concentration is elevated, as is the associated variability which reflects the variability of the urban sources. Furthermore, two sites with inlets high above ground level (EIF and TRN) show a phase shift of the CO2 diurnal cycle of a few hours compared to lower sites due to a strong coupling with the boundary layer diurnal cycle. As a consequence, the existence of a CO2 vertical gradient above Paris can be inferred, whose amplitude depends on the time of the day and on

  11. Diurnal, synoptic and seasonal variability of atmospheric CO2 in the Paris megacity area

    Directory of Open Access Journals (Sweden)

    I. Xueref-Remy

    2018-03-01

    Full Text Available Most of the global fossil fuel CO2 emissions arise from urbanized and industrialized areas. Bottom-up inventories quantify them but with large uncertainties. In 2010–2011, the first atmospheric in situ CO2 measurement network for Paris, the capital of France, began operating with the aim of monitoring the regional atmospheric impact of the emissions coming from this megacity. Five stations sampled air along a northeast–southwest axis that corresponds to the direction of the dominant winds. Two stations are classified as rural (Traînou – TRN; Montgé-en-Goële – MON, two are peri-urban (Gonesse – GON; Gif-sur-Yvette – GIF and one is urban (EIF, located on top of the Eiffel Tower. In this study, we analyze the diurnal, synoptic and seasonal variability of the in situ CO2 measurements over nearly 1 year (8 August 2010–13 July 2011. We compare these datasets with remote CO2 measurements made at Mace Head (MHD on the Atlantic coast of Ireland and support our analysis with atmospheric boundary layer height (ABLH observations made in the center of Paris and with both modeled and observed meteorological fields. The average hourly CO2 diurnal cycles observed at the regional stations are mostly driven by the CO2 biospheric cycle, the ABLH cycle and the proximity to urban CO2 emissions. Differences of several µmol mol−1 (ppm can be observed from one regional site to the other. The more the site is surrounded by urban sources (mostly residential and commercial heating, and traffic, the more the CO2 concentration is elevated, as is the associated variability which reflects the variability of the urban sources. Furthermore, two sites with inlets high above ground level (EIF and TRN show a phase shift of the CO2 diurnal cycle of a few hours compared to lower sites due to a strong coupling with the boundary layer diurnal cycle. As a consequence, the existence of a CO2 vertical gradient above Paris can be inferred, whose amplitude depends

  12. Robotic cleaning of radwaste tank nozzles

    International Nuclear Information System (INIS)

    Boughman, G.; Jones, S.L.

    1992-01-01

    The Susquehanna radwaste processing system includes two reactor water cleanup phase separator tanks and one waste sludge phase separator tank. A system of educator nozzles and associated piping is used to provide mixing in the tanks. The mixture pumped through the nozzles is a dense resin-and-water slurry, and the nozzles tend to plug up during processing. The previous method for clearing the nozzles had been for a worker to enter the tanks and manually insert a hydrolaser into each nozzle, one at a time. The significant radiation exposure and concern for worker safety in the tank led the utility to investigate alternate means for completing this task. The typical tank configuration is shown in a figure. The initial approach investigated was to insert a manipulator arm in the tank. This arm would be installed by workers and then teleoperated from a remote control station. This approach was abandoned because of several considerations including educator location and orientation, excessive installation time, and cost. The next approach was to use a mobile platform that would operate on the tank floor. This approach was selected as being the most feasible solution. After a competitive selection process, REMOTEC was selected to provide the mobile platform. Their proposal was based on the commercial ANDROS Mark 5 platform

  13. Lower nozzle of PWR fuel assembly

    International Nuclear Information System (INIS)

    Furutani, Nobuo.

    1994-01-01

    A lower nozzle comprises a regular square plate and legs. The plate has a plurality of holes for securing thimble tubes and a great number of water flowing ports. Ridges each having a lower end surface inclined toward inner side of the plate are disposed at the outer circumference of the plate. The legs suspend downwardly from the corners of the plate and support the plate at a predetermined gap between a lower reactor core plate and the plate. The inclined surfaces of the ridges disposed at the outer circumference of the plate retain coolants, that were caused to flow to the outside passing between the legs of the nozzle, while dividing them to the inside of the nozzle and circulate the coolants upwardly passing through the water flowing ports of the plate. Further, since obstacles abut against the inclined surfaces of the ridges and flow to the inner side of the lower nozzle, obstacles in the coolants can be captured substantially entirely by the lower nozzle. (I.N.)

  14. Aeroelastic Modeling of a Nozzle Startup Transient

    Science.gov (United States)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2014-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

  15. Variability of snow line elevation, snow cover area and depletion in the main Slovak basins in winters 2001–2014

    Directory of Open Access Journals (Sweden)

    Krajčí Pavel

    2016-03-01

    Full Text Available Spatial and temporal variability of snow line (SL elevation, snow cover area (SCA and depletion (SCD in winters 2001–2014 is investigated in ten main Slovak river basins (the Western Carpathians. Daily satellite snow cover maps from MODIS Terra (MOD10A1, V005 and Aqua (MYD10A1, V005 with resolution 500 m are used.

  16. Progress on Variable Cycle Engines

    Science.gov (United States)

    Westmoreland, J. S.; Howlett, R. A.; Lohmann, R. P.

    1979-01-01

    Progress in the development and future requirements of the Variable Stream Control Engine (VSCE) are presented. The two most critical components of this advanced system for future supersonic transports, the high performance duct burner for thrust augmentation, and the low jet coannular nozzle were studied. Nozzle model tests substantiated the jet noise benefit associated with the unique velocity profile possible with a coannular nozzle system on a VSCE. Additional nozzle model performance tests have established high thrust efficiency levels only at takeoff and supersonic cruise for this nozzle system. An experimental program involving both isolated component and complete engine tests has been conducted for the high performance, low emissions duct burner with good results and large scale testing of these two components is being conducted using a F100 engine as the testbed for simulating the VSCE. Future work includes application of computer programs for supersonic flow fields to coannular nozzle geometries, further experimental testing with the duct burner segment rig, and the use of the Variable Cycle Engine (VCE) Testbed Program for evaluating the VSCE duct burner and coannular nozzle technologies.

  17. Li/Li2 supersonic nozzle beam

    International Nuclear Information System (INIS)

    Wu, C.Y.R.; Crooks, J.B.; Yang, S.C.; Way, K.R.; Stwalley, W.C.

    1977-01-01

    The characterization of a lithium supersonic nozzle beam was made using spectroscopic techniques. It is found that at a stagnation pressure of 5.3 kPa (40 torr) and a nozzle throat diameter of 0.4 mm the ground state vibrational population of Li 2 can be described by a Boltzmann distribution with T/sub v/ = 195 +- 30 0 K. The rotational temperature is found to be T/sub r/ = 70 +- 20 0 K by band shape analysis. Measurements by quadrupole mass spectrometer indicates that approximately 10 mole per cent Li 2 dimers are formed at an oven body temperature of 1370 0 K n the supersonic nozzle expansion. This measured mole fraction is in good agreement with the existing dimerization theory

  18. Dual-nozzle microfluidic droplet generator

    Science.gov (United States)

    Choi, Ji Wook; Lee, Jong Min; Kim, Tae Hyun; Ha, Jang Ho; Ahrberg, Christian D.; Chung, Bong Geun

    2018-05-01

    The droplet-generating microfluidics has become an important technique for a variety of applications ranging from single cell analysis to nanoparticle synthesis. Although there are a large number of methods for generating and experimenting with droplets on microfluidic devices, the dispensing of droplets from these microfluidic devices is a challenge due to aggregation and merging of droplets at the interface of microfluidic devices. Here, we present a microfluidic dual-nozzle device for the generation and dispensing of uniform-sized droplets. The first nozzle of the microfluidic device is used for the generation of the droplets, while the second nozzle can accelerate the droplets and increase the spacing between them, allowing for facile dispensing of droplets. Computational fluid dynamic simulations were conducted to optimize the design parameters of the microfluidic device.

  19. Spatial and temporal variability of rainfall and their effects on hydrological response in urban areas – a review

    Directory of Open Access Journals (Sweden)

    E. Cristiano

    2017-07-01

    Full Text Available In urban areas, hydrological processes are characterized by high variability in space and time, making them sensitive to small-scale temporal and spatial rainfall variability. In the last decades new instruments, techniques, and methods have been developed to capture rainfall and hydrological processes at high resolution. Weather radars have been introduced to estimate high spatial and temporal rainfall variability. At the same time, new models have been proposed to reproduce hydrological response, based on small-scale representation of urban catchment spatial variability. Despite these efforts, interactions between rainfall variability, catchment heterogeneity, and hydrological response remain poorly understood. This paper presents a review of our current understanding of hydrological processes in urban environments as reported in the literature, focusing on their spatial and temporal variability aspects. We review recent findings on the effects of rainfall variability on hydrological response and identify gaps where knowledge needs to be further developed to improve our understanding of and capability to predict urban hydrological response.

  20. Thrust Augmented Nozzle for a Hybrid Rocket with a Helical Fuel Port

    Science.gov (United States)

    Marshall, Joel H.

    A thrust augmented nozzle for hybrid rocket systems is investigated. The design lever-ages 3-D additive manufacturing to embed a helical fuel port into the thrust chamber of a hybrid rocket burning gaseous oxygen and ABS plastic as propellants. The helical port significantly increases how quickly the fuel burns, resulting in a fuel-rich exhaust exiting the nozzle. When a secondary gaseous oxygen flow is injected into the nozzle downstream of the throat, all of the remaining unburned fuel in the plume spontaneously ignites. This secondary reaction produces additional high pressure gases that are captured by the nozzle and significantly increases the motor's performance. Secondary injection and combustion allows a high expansion ratio (area of the nozzle exit divided by area of the throat) to be effective at low altitudes where there would normally be significantly flow separation and possibly an embedded shock wave due. The result is a 15 percent increase in produced thrust level with no loss in engine efficiency due to secondary injection. Core flow efficiency was increased significantly. Control tests performed using cylindrical fuel ports with secondary injection, and helical fuel ports without secondary injection did not exhibit this performance increase. Clearly, both the fuel-rich plume and secondary injection are essential features allowing the hybrid thrust augmentation to occur. Techniques for better design optimization are discussed.

  1. Biannular Airbreathing Nozzle Rig (BANR) facility checkout and plug nozzle performance test data

    Science.gov (United States)

    Cummings, Chase B.

    2010-09-01

    The motivation for development of a supersonic business jet (SSBJ) platform lies in its ability to create a paradigm shift in the speed and reach of commercial, private, and government travel. A full understanding of the performance capabilities of exhaust nozzle configurations intended for use in potential SSBJ propulsion systems is critical to the design of an aircraft of this type. Purdue University's newly operational Biannular Airbreathing Nozzle Rig (BANR) is a highly capable facility devoted to the testing of subscale nozzles of this type. The high accuracy, six-axis force measurement system and complementary mass flowrate measurement capabilities of the BANR facility make it rather ideally suited for exhaust nozzle performance appraisal. Detailed accounts pertaining to methods utilized in the proper checkout of these diagnostic capabilities are contained herein. Efforts to quantify uncertainties associated with critical BANR test measurements are recounted, as well. Results of a second hot-fire test campaign of a subscale Gulfstream Aerospace Corporation (GAC) axisymmetric, shrouded plug nozzle are presented. Determined test article performance parameters (nozzle thrust efficiencies and discharge coefficients) are compared to those of a previous test campaign and numerical simulations of the experimental set-up. Recently acquired data is compared to published findings pertaining to plug nozzle experiments of similar scale and operating range. Suggestions relating to the future advancement and improvement of the BANR facility are provided. Lessons learned with regards to test operations and calibration procedures are divulged in an attempt to aid future facility users, as well.

  2. Effects of Fuel and Nozzle Characteristics on Micro Gas Turbine System: A Review

    Science.gov (United States)

    Akasha Hashim, Muhammad; Khalid, Amir; Salleh, Hamidon; Sunar, Norshuhaila Mohamed

    2017-08-01

    For many decades, gas turbines have been used widely in the internal combustion engine industry. Due to the deficiency of fossil fuel and the concern of global warming, the used of bio-gas have been recognized as one of most clean fuels in the application of engine to improve performance of lean combustion and minimize the production of NOX and PM. This review paper is to understand the combustion performance using dual-fuel nozzle for a micro gas turbine that was basically designed as a natural gas fuelled engine, the nozzle characteristics of the micro gas turbine has been modelled and the effect of multi-fuel used were investigated. The used of biogas (hydrogen) as substitute for liquid fuel (methane) at constant fuel injection velocity, the flame temperature is increased, but the fuel low rate reduced. Applying the blended fuel at constant fuel rate will increased the flame temperature as the hydrogen percentages increased. Micro gas turbines which shows the uniformity of the flow distribution that can be improved without the increase of the pressure drop by applying the variable nozzle diameters into the fuel supply nozzle design. It also identifies the combustion efficiency, better fuel mixing in combustion chamber using duel fuel nozzle with the largest potential for the future. This paper can also be used as a reference source that summarizes the research and development activities on micro gas turbines.

  3. Measurements methods and variability assesment of the Norway spruce total leaf area. Implications for remote sensing

    Czech Academy of Sciences Publication Activity Database

    Homolová, L.; Lukeš, Petr; Malenovský, Z.; Lhotáková, Z.; Kaplan, Věroslav; Hanuš, Jan

    2013-01-01

    Roč. 27, č. 1 (2013), s. 111-121 ISSN 0931-1890 R&D Projects: GA ČR GA205/09/ 1989 Institutional support: RVO:67179843 Keywords : chlorophyll content * conversion factor * Picea abies * projected leaf area * remote sensing * total leaf area Subject RIV: EH - Ecology, Behaviour Impact factor: 1.869, year: 2013

  4. Combustor nozzles in gas turbine engines

    Science.gov (United States)

    Johnson, Thomas Edward; Keener, Christopher Paul; Stewart, Jason Thurman; Ostebee, Heath Michael

    2017-09-12

    A micro-mixer nozzle for use in a combustor of a combustion turbine engine, the micro-mixer nozzle including: a fuel plenum defined by a shroud wall connecting a periphery of a forward tube sheet to a periphery of an aft tubesheet; a plurality of mixing tubes extending across the fuel plenum for mixing a supply of compressed air and fuel, each of the mixing tubes forming a passageway between an inlet formed through the forward tubesheet and an outlet formed through the aft tubesheet; and a wall mixing tube formed in the shroud wall.

  5. Variable Selection Strategies for Small-area Estimation Using FIA Plots and Remotely Sensed Data

    Science.gov (United States)

    Andrew Lister; Rachel Riemann; James Westfall; Mike Hoppus

    2005-01-01

    The USDA Forest Service's Forest Inventory and Analysis (FIA) unit maintains a network of tens of thousands of georeferenced forest inventory plots distributed across the United States. Data collected on these plots include direct measurements of tree diameter and height and other variables. We present a technique by which FIA plot data and coregistered...

  6. A Source Area Approach Demonstrates Moderate Predictive Ability but Pronounced Variability of Invasive Species Traits.

    Directory of Open Access Journals (Sweden)

    Günther Klonner

    Full Text Available The search for traits that make alien species invasive has mostly concentrated on comparing successful invaders and different comparison groups with respect to average trait values. By contrast, little attention has been paid to trait variability among invaders. Here, we combine an analysis of trait differences between invasive and non-invasive species with a comparison of multidimensional trait variability within these two species groups. We collected data on biological and distributional traits for 1402 species of the native, non-woody vascular plant flora of Austria. We then compared the subsets of species recorded and not recorded as invasive aliens anywhere in the world, respectively, first, with respect to the sampled traits using univariate and multiple regression models; and, second, with respect to their multidimensional trait diversity by calculating functional richness and dispersion metrics. Attributes related to competitiveness (strategy type, nitrogen indicator value, habitat use (agricultural and ruderal habitats, occurrence under the montane belt, and propagule pressure (frequency were most closely associated with invasiveness. However, even the best multiple model, including interactions, only explained a moderate fraction of the differences in invasive success. In addition, multidimensional variability in trait space was even larger among invasive than among non-invasive species. This pronounced variability suggests that invasive success has a considerable idiosyncratic component and is probably highly context specific. We conclude that basing risk assessment protocols on species trait profiles will probably face hardly reducible uncertainties.

  7. Development of Reactor Vessel Bottom Mount Instrumentation Nozzle Routine Inspection Device

    Energy Technology Data Exchange (ETDEWEB)

    Khaled, Atya Ahmed Abdallah; Ihn, Namgung [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2015-10-15

    The primary coolant water of pressurized water reactors has created cracks in j-weld of penetrations with Alloy 600 through a process called primary water stress corrosion cracking. On October 6, 2013, BMI nozzle number 3 at Palo Verde Unit 3 (PVNGS-3) exhibited small white de-posits around the annulus. Nozzle attachment to the RV lower head is by J-groove weld to the inside penetration of the nozzle and the weld material is of Alloy 600 material. Above two cases clearly show the necessity of routine inspection of RV lower head penetration during refueling outage. Nondestructive inspection is generally performed to detect fine cracks or defects that may develop during operation. Defects usually occur at weld regions, hence most non-destructive inspection is to scan and check any defects or crack in the weld region. BMI nozzles at the bottom head of a nuclear reactor vessel (RV) are one of such area for inspection. But BMI nozzles have not been inspected during regular refuel outage due to the relative small size of BMI nozzle and limited impact of the consequences of BMI leak. However, there is growing concern since there have been leaks at nuclear power plants (NPPs) as well as recent operating experience. In this study, we propose a system that is conveniently used for nondestructive inspection of BMI nozzles during regular refueling outage without removing all the reactor internals. A 3D model of the inspection system was also developed along with the RV and internals which permits a virtual 3D simulation to check the design concept and usability of the system.

  8. Variability of morphometric characteristics of the leaves of European white elm from the area of Great War Island

    Directory of Open Access Journals (Sweden)

    Devetaković Jovana

    2013-01-01

    Full Text Available The European White Elm (Ulmus effusa Willd. is indicated as a rare and endangered species in the growing stock of the Republic of Serbia. In the area of Great War Island, its natural populations were reduced to 56 registered trees, which occur in three spatially isolated subpopulations. On the basis of the research conducted on the level of variability of adaptible morphometric characteristics of leaves from 14 selected test trees of European White Elm, it can be concluded that the degree of interpopulation variability is satisfactory, which is a good basis for the conservation of the available gene pool.

  9. Effect of Injector Nozzle Holes on Diesel Engine Performance

    OpenAIRE

    Semin,; Yusof, Mohd Yuzri Mohd; Arof, Aminuddin Md; Shaharudin, Daneil Tomo; Ismail, Abdul Rahim

    2010-01-01

    All of the injector nozzle holes have examined and the results are shown that the seven holes nozzle have provided the best burning result for the fuel in-cylinder burned in any different engine speeds and the best burning is in low speed engine. In engine performance effect, all of the nozzles have examined and the five holes nozzle provided the best result in indicted power, indicated torque and ISFC in any different engine speeds.

  10. Effect of jet nozzle geometry on flow and heat transfer performance of vortex cooling for gas turbine blade leading edge

    International Nuclear Information System (INIS)

    Du, Changhe; Li, Liang; Wu, Xin; Feng, Zhenping

    2016-01-01

    Highlights: • We establish a suitable vortex chamber model for gas turbine blade leading edge. • Mechanism of vortex cooling is further discussed and presented. • Influences of jet nozzle geometry on vortex cooling characteristics are researched. • This paper focuses on assessment of flow field and thermal performance for different jet nozzle aspect ratio and area. - Abstract: In this paper, 3D viscous steady Reynolds Averaged Navier–Stokes (RANS) equations are utilized to investigate the influence of jet nozzle geometry on flow and thermal behavior of vortex cooling for gas turbine blades. Comparison between calculation with different turbulence models and the experimental data is conducted, and results show that the standard k-ω model provides the best accuracy. The grid independence analysis is performed to obtain the proper mesh number. First, the mechanism of vortex cooling is further discussed, and the pronounced impact of kinetic turbulence intensity, thin thermal boundary layer, violent radial convection and complex vortices on enhanced heat transfer performance is confirmed. Then, seven jet nozzle aspect ratios and seven jet nozzle to chamber cross section area ratios are selected to research the flow field and thermal characteristics of vortex cooling focusing on the streamline, static pressure ratio, total pressure loss ratio and Nusselt number. It is presented that the jet nozzle aspect ratio and jet nozzle to chamber cross section area ratio both impose a significant effect on the flow and thermal parameters. The averaged Nusselt number decreases at first and then increases with the increasing jet nozzle aspect ratio, reaching highest when aspect ratio equals to 1. The effect of area ratio on averaged Nusselt number is complex. Finally, the heat transfer results in this study are compared with other previous works. Results indicate that good agreement with previous data is achieved, and the enhanced thermal behavior may be acquired by

  11. Increased variability of watershed areas in patients with high-grade carotid stenosis

    DEFF Research Database (Denmark)

    Kaczmarz, Stephan; Griese, Vanessa; Preibisch, Christine

    2018-01-01

    . Despite of high relevance for both clinical diagnostics and research, individual in vivo WSA definition is fairly limited to date. Thus, this study proposes a standardized segmentation approach to delineate individual WSAs by use of time-to-peak (TTP) maps and investigates spatial variability...... of individual WSAs. Methods: We defined individual watershed masks based on relative TTP increases in 30 healthy elderly persons and 28 patients with unilateral, high-grade carotid stenosis, being at risk for watershed-related hemodynamic impairment. Determined WSA location was confirmed by an arterial transit...... time atlas and individual super-selective arterial spin labeling. We compared spatial variability of WSA probability maps between groups and assessed TTP differences between hemispheres in individual and group-average watershed locations. Results: Patients showed significantly higher spatial...

  12. Research Amplitudo Vibration On Holder Due To The Process Of Lathe Nozzle Rocket RX 450

    Science.gov (United States)

    Ediwan; Budi Djatmiko, Agus; Dody Arisandi, EfFendy; Purnomo, Heri; Ibadi, Mahfud

    2018-04-01

    The main function of the rocket nozzle is to convert the enthalpy efficiency from combustion gas to kinetic energy and also to make high velocity out of the gas. The rocket nozzle usually consists of a converging and diverging part. With a smaller area on the neck and enlarged at the exit area. The velocity flow through the nozzle enlarges into the speed of sound through the neck and then becomes super sonic in the divergent part. Nozzle making or machining using conventional lathes, first performed is drilling on a massive metal that is bonded to the veneer, then after a sufficient gap is done deep-boring. At the time of the process of lathe in the nozzle RX 450 there is an obstacle that is vibrating tool holder chisel or holder so it is worried about not precision of the process of lathe. This should not happen because it can cause failure in the latter for it needs to be studied and studied further so that the lathe process goes accordingly. The holder material of ST 60 with a modulus of elasticity 200 GPa and a nozzle material of AISI 4340 alloy steel with σyield = 470 MPa, Shear Modulus G = 80 GPa. The purpose of this research is to observe the amplitude of vibration on the holder due to RX- 450 nozzle lathe processing for the purpose of amplitude that occurs in accordance with the desired so that the nozzle structure is no damage process. The result of the research was obtained holder with length (L) 80cm, profile width (B) 5 cm, height of profile (H) 10 cm, turning machine ω = 8.98 rad / sec and natural holder frequency ωn = 89.8 rad / second, Amplitude of vibration of δ = 1.21 mm, while the amplitude of the design X = 1.22 mm From the results of this study it can be said that the holder of a chisel or holder can be used as a tool at the time of RX nozzle retrieval process and is quite safe because it works under the condition ω/ω n Rocket Payload "AKPV Engineering University of Wyoming 2009 )

  13. Climate variability in the subarctic area for the last 2 millennia

    Science.gov (United States)

    Nicolle, Marie; Debret, Maxime; Massei, Nicolas; Colin, Christophe; deVernal, Anne; Divine, Dmitry; Werner, Johannes P.; Hormes, Anne; Korhola, Atte; Linderholm, Hans W.

    2018-01-01

    To put recent climate change in perspective, it is necessary to extend the instrumental climate records with proxy data from paleoclimate archives. Arctic climate variability for the last 2 millennia has been investigated using statistical and signal analyses from three regionally averaged records from the North Atlantic, Siberia and Alaska based on many types of proxy data archived in the Arctic 2k database v1.1.1. In the North Atlantic and Alaska, the major climatic trend is characterized by long-term cooling interrupted by recent warming that started at the beginning of the 19th century. This cooling is visible in the Siberian region at two sites, warming at the others. The cooling of the Little Ice Age (LIA) was identified from the individual series, but it is characterized by wide-range spatial and temporal expression of climate variability, in contrary to the Medieval Climate Anomaly. The LIA started at the earliest by around AD 1200 and ended at the latest in the middle of the 20th century. The widespread temporal coverage of the LIA did not show regional consistency or particular spatial distribution and did not show a relationship with archive or proxy type either. A focus on the last 2 centuries shows a recent warming characterized by a well-marked warming trend parallel with increasing greenhouse gas emissions. It also shows a multidecadal variability likely due to natural processes acting on the internal climate system on a regional scale. A ˜ 16-30-year cycle is found in Alaska and seems to be linked to the Pacific Decadal Oscillation, whereas ˜ 20-30- and ˜ 50-90-year periodicities characterize the North Atlantic climate variability, likely in relation with the Atlantic Multidecadal Oscillation. These regional features are probably linked to the sea ice cover fluctuations through ice-temperature positive feedback.

  14. Climate variability in the subarctic area for the last 2 millennia

    Directory of Open Access Journals (Sweden)

    M. Nicolle

    2018-01-01

    Full Text Available To put recent climate change in perspective, it is necessary to extend the instrumental climate records with proxy data from paleoclimate archives. Arctic climate variability for the last 2 millennia has been investigated using statistical and signal analyses from three regionally averaged records from the North Atlantic, Siberia and Alaska based on many types of proxy data archived in the Arctic 2k database v1.1.1. In the North Atlantic and Alaska, the major climatic trend is characterized by long-term cooling interrupted by recent warming that started at the beginning of the 19th century. This cooling is visible in the Siberian region at two sites, warming at the others. The cooling of the Little Ice Age (LIA was identified from the individual series, but it is characterized by wide-range spatial and temporal expression of climate variability, in contrary to the Medieval Climate Anomaly. The LIA started at the earliest by around AD 1200 and ended at the latest in the middle of the 20th century. The widespread temporal coverage of the LIA did not show regional consistency or particular spatial distribution and did not show a relationship with archive or proxy type either. A focus on the last 2 centuries shows a recent warming characterized by a well-marked warming trend parallel with increasing greenhouse gas emissions. It also shows a multidecadal variability likely due to natural processes acting on the internal climate system on a regional scale. A ∼ 16–30-year cycle is found in Alaska and seems to be linked to the Pacific Decadal Oscillation, whereas ∼ 20–30- and ∼ 50–90-year periodicities characterize the North Atlantic climate variability, likely in relation with the Atlantic Multidecadal Oscillation. These regional features are probably linked to the sea ice cover fluctuations through ice–temperature positive feedback.

  15. CFD Analysis On The Performance Of Wind Turbine With Nozzles

    Directory of Open Access Journals (Sweden)

    Chunkyraj Kh

    2015-08-01

    Full Text Available In this paper an effort has been made in dealing with fluid characteristic that enters a converging nozzle and analysis of the nozzle is carried out using Computational Fluid Dynamics package ANSYS WORKBENCH 14.5. The paper is the continuation of earlier work Analytical and Experimental performance evaluation of Wind turbine with Nozzles. First the CFD analysis will be carried out on nozzle in-front of wind turbine where streamline velocity at the exit volume flow rate in the nozzle and pressure distribution across the nozzle will be studied. Experiments were conducted on the Wind turbine with nozzles and the corresponding power output at different air speed and different size of nozzles were calculated. Different shapes and dimensions with special contours and profiles of nozzles were studied. It was observed that the special contour nozzles have superior outlet velocity and low pressure at nozzle exit the design has maximum Kinetic energy. These indicators conclude that the contraction designed with the new profile is a good enhancing of the nozzle performance.

  16. Cavitation characteristics of multihole diesel-fuel nozzles in high-speed oil flows. Diesel kikan yo nenryo tako nozzle no abura cavitation tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, M. (Shimonoseki Univ. of Fisheris, Yamaguchi (Japan)); Ito, Y. (Hachinohe Inst. of Tech., Aomori (Japan)); Aoki, H. (Xexel-Gleason U.S.A. Inc., New York (U.S.A))

    1991-07-25

    Recently, since higher velocity and higher pressure are required for diesel injection systems, cavitation behaviors in high velocity oil flows are strongly interested in such as 100 to 500 m/s for oil flow velocity and less than the cavitation factor {sigma} of 0.01. In this paper, oil cavitation characteristics at the injection part of multihole nozzles, especially on the flow characteristics, were studied systematically using fuel injection multihole nozzles for an actual use. As a result, it was clarified that subcavitation area (sub C), transition area, and supercavitation area (SC) could be existing in C{sub d}-{sigma} relation, which was similar to that specified cavitation conditions could be exisiting in the actual working area of multihole nozzles. And it was also clarified that flow coefficient C{sub d} relied on Reynolds number R{sub e} in the transition of {sigma}{ge}{sigma}{sub cr} and in {sub C} area, and mainly relied on {sigma} in SC area of {sigma}<{sigma}{sub cr}. Moreover, it was also confirmed that such tendency was similar to the one of the two-dimensional contraction of an area. 22 refs., 10 figs., 1 tab.

  17. Shock wave fabricated ceramic-metal nozzles

    NARCIS (Netherlands)

    Carton, E.P.; Stuivinga, M.E.C.; Keizers, H.L.J.; Verbeek, H.J.; Put, P.J. van der

    1999-01-01

    Shock compaction was used in the fabrication of high temperature ceramic-based materials. The materials' development was geared towards the fabrication of nozzles for rocket engines using solid propellants, for which the following metal-ceramic (cermet) materials were fabricated and tested: B4C-Ti

  18. Clamp and Gas Nozzle for TIG Welding

    Science.gov (United States)

    Gue, G. B.; Goller, H. L.

    1982-01-01

    Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

  19. Fabrication of Microglass Nozzle for Microdroplet Jetting

    Directory of Open Access Journals (Sweden)

    Dan Xie

    2015-02-01

    Full Text Available An ejection aperture nozzle is the essential part for all microdrop generation techniques. The diameter size, the flow channel geometry, and fluid impedance are the key factors affecting the ejection capacity. A novel low-cost fabrication method of microglass nozzle involving four steps is developed in this work. In the first heating step, the glass pipette is melted and pulled. Then, the second heating step is to determine the tip cone angle and modify the flow channel geometry. The desired included angle is usually of 30~45 degrees. Fine grind can determine the exact diameter of the hole. Postheating step is the final process and it can reduce the sharpness of the edges of the hole. Micronozzles with hole diameters varying from 30 to 100 µm are fabricated by the homemade inexpensive and easy-to-operate setup. Hydrophobic treating method of microglass nozzle to ensure stable and accurate injection is also introduced in this work. According to the jetting results of aqueous solution, UV curing adhesive, and solder, the fabricated microglass nozzle can satisfy the need of microdroplet jetting of multimaterials.

  20. Microalgal cell disruption via ultrasonic nozzle spraying.

    Science.gov (United States)

    Wang, M; Yuan, W

    2015-01-01

    The objective of this study was to understand the effect of operating parameters, including ultrasound amplitude, spraying pressure, nozzle orifice diameter, and initial cell concentration on microalgal cell disruption and lipid extraction in an ultrasonic nozzle spraying system (UNSS). Two algal species including Scenedesmus dimorphus and Nannochloropsis oculata were evaluated. Experimental results demonstrated that the UNSS was effective in the disruption of microalgal cells indicated by significant changes in cell concentration and Nile red-stained lipid fluorescence density between all treatments and the control. It was found that increasing ultrasound amplitude generally enhanced cell disruption and lipid recovery although excessive input energy was not necessary for best results. The effect of spraying pressure and nozzle orifice diameter on cell disruption and lipid recovery was believed to be dependent on the competition between ultrasound-induced cavitation and spraying-generated shear forces. Optimal cell disruption was not always achieved at the highest spraying pressure or biggest nozzle orifice diameter; instead, they appeared at moderate levels depending on the algal strain and specific settings. Increasing initial algal cell concentration significantly reduced cell disruption efficiency. In all UNSS treatments, the effectiveness of cell disruption and lipid recovery was found to be dependent on the algal species treated.

  1. Design criteria for piping and nozzles program

    International Nuclear Information System (INIS)

    Moore, S.E.; Bryson, J.W.

    1977-01-01

    This report reviews the activities and accomplishments of the Design Criteria for Piping and Nozzles program being conducted by the Oak Ridge National Laboratory for the period July 1, 1975, to September 30, 1976. The objectives of the program are to conduct integrated experimental and analytical stress analysis studies of piping system components and isolated and closely-spaced pressure vessel nozzles in order to confirm and/or improve the adequacy of structural design criteria and analytical methods used to assure the safe design of nuclear power plants. Activities this year included the development of a finite-element program for analyzing two closely spaced nozzles in a cylindrical pressure vessel; a limited-parameter study of vessels with isolated nozzles, finite-element studies of piping elbows, a fatigue test of an out-of-round elbow, summary and evaluation of experimental studies on the elastic-response and fatigue failure of tees, parameter studies on the behavior of flanged joints, publication of fifteen topical reports and papers on various experimental and analytical studies; and the development and acceptance of a number of design rules changes to the ASME Code. 2 figures, 2 tables

  2. Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators

    Science.gov (United States)

    Meitner, P. L.; Glassman, A. J.

    1980-01-01

    An off-design performance loss model for a radial turbine with pivoting, variable-area stators is developed through a combination of analytical modeling and experimental data analysis. A viscous loss model is used for the variation in stator loss with setting angle, and stator vane end-clearance leakage effects are predicted by a clearance flow model. The variation of rotor loss coefficient with stator setting angle is obtained by means of an analytical matching of experimental data for a rotor that was tested with six stators, having throat areas from 20 to 144% of the design area. An incidence loss model is selected to obtain best agreement with experimental data. The stator vane end-clearance leakage model predicts increasing mass flow and decreasing efficiency as a result of end-clearances, with changes becoming significantly larger with decreasing stator area.

  3. Pore-scale modeling of vapor transport in partially saturated capillary tube with variable area using chemical potential

    DEFF Research Database (Denmark)

    Addassi, Mouadh; Schreyer, Lynn; Johannesson, Björn

    2016-01-01

    Here we illustrate the usefulness of using the chemical potential as the primary unknown by modeling isothermal vapor transport through a partially saturated cylindrically symmetric capillary tube of variable cross-sectional area using a single equation. There are no fitting parameters and the nu......Here we illustrate the usefulness of using the chemical potential as the primary unknown by modeling isothermal vapor transport through a partially saturated cylindrically symmetric capillary tube of variable cross-sectional area using a single equation. There are no fitting parameters...... and the numerical solutions to the equation are compared with experimental results with excellent agreement. We demonstrate that isothermal vapor transport can be accurately modeled without modeling the details of the contact angle, microscale temperature fluctuations, or pressure fluctuations using a modification...

  4. Spatial variability of soil pH based on GIS combined with geostatistics in Panzhihua tobacco area

    International Nuclear Information System (INIS)

    Du Wei; Wang Changquan; Li Bing; Li Qiquan; Du Qian; Hu Jianxin; Liu Chaoke

    2012-01-01

    GIS and geostatistics were utilized to study the spatial variability of soil pH in Panzhihua tobacco area. Results showed that pH values in this area ranged from 4.5 to 8.3, especially 5.5 to 6.5, and in few areas were lower than 5.0 or higher than 7.0 which can meet the need of high-quality tobacco production. The best fitting model of variogram was exponential model with the nugget/sill of soil pH in 13.61% indicating strong spatial correlation. The change process was 5.40 km and the coefficient of determination was 0.491. The spatial variability of soil pH was mainly caused by structural factors such as cane, topography and soil type. The soil pH in Panzhihua tobacco area also showed a increasing trend of northwest to southeast trend. The pH of some areas in Caochang, Gonghe and Yumen were lower, and in Dalongtan were slightly higher. (authors)

  5. Seasonal variability of leaf area index and foliar nitrogen in contrasting dry-mesic tundras

    DEFF Research Database (Denmark)

    Campioli, Matteo; Michelsen, Anders; Lemeur, Raoul

    2009-01-01

    Assimilation and exchange of carbon for arctic ecosystems depend strongly on leaf area index (LAI) and total foliar nitrogen (TFN). For dry-mesic tundras, the seasonality of these characteristics is unexplored. We addressed this knowledge gap by measuring variations of LAI and TFN at five contras...

  6. Measurement methods and variability assessment of the Norway spruce total leaf area: Implications for remote sensing

    NARCIS (Netherlands)

    Homolova, L.; Lukes, P.; Malenovsky, Z.; Lhotakova, Z.; Kaplan, V.; Hanus, J.

    2013-01-01

    Estimation of total leaf area (LAT) is important to express biochemical properties in plant ecology and remote sensing studies. A measurement of LAT is easy in broadleaf species, but it remains challenging in coniferous canopies. We proposed a new geometrical model to estimate Norway spruce LAT and

  7. Ultra low injection angle fuel holes in a combustor fuel nozzle

    Science.gov (United States)

    York, William David

    2012-10-23

    A fuel nozzle for a combustor includes a mixing passage through which fluid is directed toward a combustion area and a plurality of swirler vanes disposed in the mixing passage. Each swirler vane of the plurality of swirler vanes includes at least one fuel hole through which fuel enters the mixing passage in an injection direction substantially parallel to an outer surface of the plurality of swirler vanes thereby decreasing a flameholding tendency of the fuel nozzle. A method of operating a fuel nozzle for a combustor includes flowing a fluid through a mixing passage past a plurality of swirler vanes and injecting a fuel into the mixing passage in an injection direction substantially parallel to an outer surface of the plurality of swirler vanes.

  8. CFD Analysis of Nozzle Exit Position Effect in Ejector Gas Removal System in Geothermal Power Plant

    Directory of Open Access Journals (Sweden)

    Setyo Nugroho

    2015-06-01

    Full Text Available The single stage ejector is used to extract the Non CondensableGas (NCG in the condenser using the working principle of the Venturi tube. Three dimensional computational simulation of the ejector according to the operating conditions was conducted to determine the flow in the ejector. Motive steam entering through the convergent – divergent nozzle with increasing flow velocity so that the low pressure exist around the nozzle. Comparison is done also in a two dimensional simulation to know the differences occurring phenomena and flow inside ejector. Different simulation results obtained between two dimensional and three dimensional simulation. Reverse flow which occurs in the mixing chamber made the static pressure in the area has increased dramatically. Then the variation performed on Exit Nozzle Position (NXP to determine the changes of the flow of the NCG and the vacuum level of the ejector. Keywords: Ejector, NCG, CFD, Compressible flow.

  9. Brazing and diffusion bonding processes as available repair techniques for gas turbine blades and nozzles

    International Nuclear Information System (INIS)

    Mazur, Z.

    1997-01-01

    The conventionally welding methods are not useful for repair of heavily damaged gas turbine blades and nozzles. It includes thermal fatigue and craze cracks, corrosion, erosion and foreign object damage, which extend to the large areas. Because of required extensive heat input and couponing, it can cause severe distortion of the parts and cracks in the heat affected zone, and can made the repair costs high. For these cases, the available repair methods of gas turbine blades and nozzles, include brazing and diffusion bonding techniques are presented. Detailed analysis of the brazing and diffusion bonding processes applied for gas turbine blades repair with all elements which presented. Detailed analysis of the brazing and diffusion bonding processes applied for gas turbine blades repair with all elements which have influence to get sound joint is carried out. Depend of kind of blades and nozzle damage or deterioration registered a different methods of brazing and diffusion bonding applicability is presented. (Author) 65 refs

  10. Area vs. density: influence of visual variables and cardinality knowledge in early number comparison.

    Science.gov (United States)

    Abreu-Mendoza, Roberto A; Soto-Alba, Elia E; Arias-Trejo, Natalia

    2013-01-01

    Current research in the number development field has focused in individual differences regarding the acuity of children's approximate number system (ANS). The most common task to evaluate children's acuity is through non-symbolic numerical comparison. Efforts have been made to prevent children from using perceptual cues by controlling the visual properties of the stimuli (e.g., density, contour length, and area); nevertheless, researchers have used these visual controls interchangeably. Studies have also tried to understand the relation between children's cardinality knowledge and their performance in a number comparison task; divergent results may in fact be rooted in the use of different visual controls. The main goal of the present study is to explore how the usage of different visual controls (density, total filled area, and correlated and anti-correlated area) affects children's performance in a number comparison task, and its relationship to children's cardinality knowledge. For that purpose, 77 preschoolers participated in three tasks: (1) counting list elicitation to test whether children could recite the counting list up to ten, (2) give a number to evaluate children's cardinality knowledge, and (3) number comparison to evaluate their ability to compare two quantities. During this last task, children were asked to point at the set with more geometric figures when two sets were displayed on a screen. Children were exposed only to one of the three visual controls. Results showed that overall, children performed above chance in the number comparison task; nonetheless, density was the easiest control, while correlated and anti-correlated area was the most difficult in most cases. Only total filled area was sensitive to discriminate cardinal principal knowers from non-cardinal principal knowers. How this finding helps to explain conflicting evidence from previous research, and how the present outcome relates to children's number word knowledge is discussed.

  11. Variability in estimated runoff in a forested area based on different cartographic data sources

    Energy Technology Data Exchange (ETDEWEB)

    Fragoso, L.; Quirós, E.; Durán-Barroso, P.

    2017-11-01

    Aim of study: The goal of this study is to analyse variations in curve number (CN) values produced by different cartographic data sources in a forested watershed, and determine which of them best fit with measured runoff volumes. Area of study: A forested watershed located in western Spain. Material and methods: Four digital cartographic data sources were used to determine the runoff CN in the watershed. Main results: None of the cartographic sources provided all the information necessary to determine properly the CN values. Our proposed methodology, focused on the tree canopy cover, improves the achieved results. Research highlights: The estimation of the CN value in forested areas should be attained as a function of tree canopy cover and new calibrated tables should be implemented in a local scale.

  12. Resource communication: Variability in estimated runoff in a forested area based on different cartographic data sources

    Directory of Open Access Journals (Sweden)

    Laura Fragoso

    2017-10-01

    Full Text Available Aim of study: The goal of this study is to analyse variations in curve number (CN values produced by different cartographic data sources in a forested watershed, and determine which of them best fit with measured runoff volumes. Area of study: A forested watershed located in western Spain. Material and methods: Four digital cartographic data sources were used to determine the runoff CN in the watershed. Main results: None of the cartographic sources provided all the information necessary to determine properly the CN values. Our proposed methodology, focused on the tree canopy cover, improves the achieved results. Research highlights: The estimation of the CN value in forested areas should be attained as a function of tree canopy cover and new calibrated tables should be implemented in a local scale.

  13. Design and analysis approach for linear aerospike nozzle

    International Nuclear Information System (INIS)

    Khan, S.U.; Khan, A.A.; Munir, A.

    2014-01-01

    The paper presents an aerodynamic design of a simplified linear aerospike nozzle and its detailed exhaust flow analysis with no spike truncation. Analytical method with isentropic planar flow was used to generate the nozzle contour through MATLAB . The developed code produces a number of outputs comprising nozzle wall profile, flow properties along the nozzle wall, thrust coefficient, thrust, as well as amount of nozzle truncation. Results acquired from design code and numerical analyses are compared for observing differences. The numerical analysis adopted an inviscid model carried out through commercially available and reliable computational fluid dynamics (CFD) software. Use of the developed code would assist the readers to perform quick analysis of different aerodynamic design parameters for the aerospike nozzle that has tremendous scope of application in future launch vehicles. Keyword: Rocket propulsion, Aerospike Nozzle, Control Design, Computational Fluid Dynamics. (author)

  14. Nuclear thermal rocket nozzle testing and evaluation program

    International Nuclear Information System (INIS)

    Davidian, K.O.; Kacynski, K.J.

    1993-01-01

    Performance characteristics of the Nuclear Thermal Rocket can be enhanced through the use of unconventional nozzles as part of the propulsion system. In this report, the Nuclear Thermal Rocket nozzle testing and evaluation program being conducted at the NASA Lewis Research Center is outlined and the advantages of a plug nozzle are described. A facility description, experimental designs and schematics are given. Results of pretest performance analyses show that high nozzle performance can be attained despite substantial nozzle length reduction through the use of plug nozzles as compared to a convergent-divergent nozzle. Pretest measurement uncertainty analyses indicate that specific impulse values are expected to be within plus or minus 1.17%

  15. On a random area variable arising in discrete-time queues and compact directed percolation

    International Nuclear Information System (INIS)

    Kearney, Michael J

    2004-01-01

    A well-known discrete-time, single-server queueing system with mean arrival rate λ and mean departure rate μ is considered from the perspective of the area, A, swept out by the queue occupation process during a busy period. We determine the exact form of the tail of the distribution, Pr(A > x); in particular, we show that Pr(A > x) ∼ Cx -1/4 exp(-Dx 1/2 ) for all ρ ≠ 1, where ρ ≡ λ/μ, and expressions for C and D are given. For the critical case ρ = 1 we show that Pr(A > x) ∼ C'x -1/3 , with C' also given. A simple mapping, used in the derivation, establishes a connection with compact directed percolation on a square lattice. As a corollary, therefore, we are also able to specify the large-area asymptotic behaviour of this model at all points in the phase diagram. This extends previous scaling results, which are only valid close to the percolation threshold

  16. Variability and scaling of hydraulic properties for 200 Area soils, Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Khaleel, R.; Freeman, E.J.

    1995-10-01

    Over the years, data have been obtained on soil hydraulic properties at the Hanford Site. Much of these data have been obtained as part of recent site characterization activities for the Environmental Restoration Program. The existing data on vadose zone soil properties are, however, fragmented and documented in reports that have not been formally reviewed and released. This study helps to identify, compile, and interpret all available data for the principal soil types in the 200 Areas plateau. Information on particle-size distribution, moisture retention, and saturated hydraulic conductivity (K{sub s}) is available for 183 samples from 12 sites in the 200 Areas. Data on moisture retention and K{sub s} are corrected for gravel content. After the data are corrected and cataloged, hydraulic parameters are determined by fitting the van Genuchten soil-moisture retention model to the data. A nonlinear parameter estimation code, RETC, is used. The unsaturated hydraulic conductivity relationship can subsequently be predicted using the van Genuchten parameters, Mualem`s model, and laboratory-measured saturated hydraulic conductivity estimates. Alternatively, provided unsaturated conductivity measurements are available, the moisture retention curve-fitting parameters, Mualem`s model, and a single unsaturated conductivity measurement can be used to predict unsaturated conductivities for the desired range of field moisture regime.

  17. Combination of individual tree detection and area-based approach in imputation of forest variables using airborne laser data

    Science.gov (United States)

    Vastaranta, Mikko; Kankare, Ville; Holopainen, Markus; Yu, Xiaowei; Hyyppä, Juha; Hyyppä, Hannu

    2012-01-01

    The two main approaches to deriving forest variables from laser-scanning data are the statistical area-based approach (ABA) and individual tree detection (ITD). With ITD it is feasible to acquire single tree information, as in field measurements. Here, ITD was used for measuring training data for the ABA. In addition to automatic ITD (ITD auto), we tested a combination of ITD auto and visual interpretation (ITD visual). ITD visual had two stages: in the first, ITD auto was carried out and in the second, the results of the ITD auto were visually corrected by interpreting three-dimensional laser point clouds. The field data comprised 509 circular plots ( r = 10 m) that were divided equally for testing and training. ITD-derived forest variables were used for training the ABA and the accuracies of the k-most similar neighbor ( k-MSN) imputations were evaluated and compared with the ABA trained with traditional measurements. The root-mean-squared error (RMSE) in the mean volume was 24.8%, 25.9%, and 27.2% with the ABA trained with field measurements, ITD auto, and ITD visual, respectively. When ITD methods were applied in acquiring training data, the mean volume, basal area, and basal area-weighted mean diameter were underestimated in the ABA by 2.7-9.2%. This project constituted a pilot study for using ITD measurements as training data for the ABA. Further studies are needed to reduce the bias and to determine the accuracy obtained in imputation of species-specific variables. The method could be applied in areas with sparse road networks or when the costs of fieldwork must be minimized.

  18. Larval fish variability in response to oceanographic features in a nearshore nursery area.

    Science.gov (United States)

    Pattrick, P; Strydom, N A

    2014-09-01

    The influence of oceanographic features on ichthyoplankton assemblages in the warm temperate nearshore region of Algoa Bay, South Africa, was assessed. The nearshore ichthyoplankton comprised 88 taxa from 34 families. Samples were collected at six stations between August 2010 and July 2012 using a plankton ring net of 750 mm diameter and 500 µm mesh aperture. The majority of larvae collected were in a preflexion stage, indicating the potential importance of the nearshore for newly hatched larvae. Engraulidae dominated the catch (38·4%), followed by Cynoglossidae (28·1%) and Sparidae (8·4%). Larval fish abundance was highest during austral spring and summer (September to February). Unique patterns in responses of each dominant fish species to oceanographic features in the nearshore indicate the sensitivity of the early developmental stage to environmental variables. Using generalized linear models, ichthyoplankton abundance responded positively to upwelling and when warm water plumes originating from an Agulhas Current meander entered Algoa Bay. Highest abundances of Engraulis encrasicolus and Sardinops sagax were observed during Agulhas Plume intrusions into Algoa Bay. When a mixed and stratified water column persisted in the nearshore region of Algoa Bay, larval fish abundance decreased. The nearshore region of Algoa Bay appears to serve as a favourable environment for the accumulation of ichthyoplankton. © 2014 The Fisheries Society of the British Isles.

  19. Jet-Surface Interaction: High Aspect Ratio Nozzle Test, Nozzle Design and Preliminary Data

    Science.gov (United States)

    Brown, Clifford; Dippold, Vance

    2015-01-01

    The Jet-Surface Interaction High Aspect Ratio (JSI-HAR) nozzle test is part of an ongoing effort to measure and predict the noise created when an aircraft engine exhausts close to an airframe surface. The JSI-HAR test is focused on parameters derived from the Turbo-electric Distributed Propulsion (TeDP) concept aircraft which include a high-aspect ratio mailslot exhaust nozzle, internal septa, and an aft deck. The size and mass flow rate limits of the test rig also limited the test nozzle to a 16:1 aspect ratio, half the approximately 32:1 on the TeDP concept. Also, unlike the aircraft, the test nozzle must transition from a single round duct on the High Flow Jet Exit Rig, located in the AeroAcoustic Propulsion Laboratory at the NASA Glenn Research Center, to the rectangular shape at the nozzle exit. A parametric nozzle design method was developed to design three low noise round-to-rectangular transitions, with 8:1, 12:1, and 16: aspect ratios, that minimizes flow separations and shocks while providing a flat flow profile at the nozzle exit. These designs validated using the WIND-US CFD code. A preliminary analysis of the test data shows that the actual flow profile is close to that predicted and that the noise results appear consistent with data from previous, smaller scale, tests. The JSI-HAR test is ongoing through October 2015. The results shown in the presentation are intended to provide an overview of the test and a first look at the preliminary results.

  20. Variable exchange between a stream and an aquifer in the Rio Grande Project Area

    Science.gov (United States)

    Sheng, Z.; Abudu, S.; Michelsen, A.; King, P.

    2016-12-01

    Both surface water and groundwater in the Rio Grande Project area in southern New Mexico and Far West Texas have been stressed by natural conditions such as droughts and human activities, including urban development and agricultural irrigation. In some area pumping stress in the aquifer becomes so great that it depletes the river flow especially during the irrigation season, typically from March through October. Therefore understanding such relationship between surface water and groundwater becomes more important in regional water resources planning and management. In this area, stream flows are highly regulated by the upstream reservoirs during the irrigation season and greatly influenced by return flows during non-irrigation season. During a drought additional groundwater pumping to supplement surface water shortage further complicates the surface water and groundwater interaction. In this paper the authors will use observation data and results of numerical models (MODFLOW) to characterize and quantify hydrological exchange fluxes between groundwater in the aquifers and surface water as well as impacts of groundwater pumping. The interaction shows a very interesting seasonal variation (irrigation vs. non-irrigation) as well as impact of a drought. Groundwater has been pumped for both municipal supplies and agricultural irrigation, which has imposed stresses toward both stream flows and aquifer storage. The results clearly show that historic groundwater pumping has caused some reaches of the river change from gaining stream to losing stream. Beyond the exchange between surface water and groundwater in the shallow aquifer, groundwater pumping in a deep aquifer could also enhance the exchanges between different aquifers through leaky confining layers. In the earlier history of pumping, pumping from the shallow aquifer is compensated by simple depletion of surface water, while deep aquifer tends to use the aquifer storage. With continued pumping, the cumulative

  1. Seasonal and inter-annual variability of sea surface temperature at the east coast fishing area off Peninsular Malaysia

    Science.gov (United States)

    Nurul Ridani, S.; Mustapha, M. A.; Lihan, T.; Ku Kassim, K. Y.; Raja Bidin, R. H.

    2015-09-01

    Empirical orthogonal function (EOF) analysis was used to study a time-series of the aqua MODIS data imageries in the exclusive economic zone of east coast off Peninsular Malaysia. Temporal and spatial characteristics were examined to determine the dominant pattern of sea surface temperature (SST) variability from January 2003 to December 2011.The data were analysed from daily Level 1A (1km spatial resolution) to monthly composites Level 3 data using SeaDAS and ERDAS imagine software. Four modes was obtained from the analysis with the highest variance (7.9%) represented by mode 1 which explained the seasonal cycle. Mode 2 (5.11 % of total variance) showed positive and negative peak signal during March and April and in October and November with variability near the Kelantan and Pahang waters that indicated the inter monsoon. Mode 3 (3.8 % of variance) shows variability near the Terengganu, Kelantan and Johor waters to the open sea during July and August and in May and June representing the Southwest monsoon. Mode 4 (3.36 %) showed positive signal during November and December with strong signal near Pahang and Kelantan waters while weak signal was detected near Terengganu and Kelantan's open sea representing the Northeast monsoon. The SST variability was influenced by the monsoonal system which originated by the wind forcing condition that influences circulation in the study area.

  2. Space and time variability of heating requirements for greenhouse tomato production in the Euro-Mediterranean area.

    Science.gov (United States)

    Mariani, Luigi; Cola, Gabriele; Bulgari, Roberta; Ferrante, Antonio; Martinetti, Livia

    2016-08-15

    The Euro-Mediterranean area is the seat of a relevant greenhouse activity, meeting the needs of important markets. A quantitative assessment of greenhouse energy consumption and of its variability in space and time is an important decision support tool for both greenhouse-sector policies and farmers. A mathematical model of greenhouse energy balance was developed and parameterized for a state-of-the-art greenhouse to evaluate the heating requirements for vegetables growing. Tomato was adopted as reference crop, due to its high energy requirement for fruit setting and ripening and its economic relevance. In order to gain a proper description of the Euro-Mediterranean area, 56 greenhouse areas located within the ranges 28°N-72°N and 11°W-55°E were analyzed over the period 1973-2014. Moreover, the two 1973-1987 and 1988-2014 sub-periods were separately studied to describe climate change effects on energy consumption. Results account for the spatial variability of energy needs for tomato growing, highlighting the strong influence of latitude on the magnitude of heat requirements. The comparison between the two selected sub-periods shows a decrease of energy demand in the current warm phase, more relevant for high latitudes. Finally, suggestions to reduce energy consumptions are provided. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. The genetic variability of the Podolica cattle breed from the Gargano area. Preliminary results

    Directory of Open Access Journals (Sweden)

    Dario Cianci

    2010-01-01

    Full Text Available The Podolica cattle breed is autochthonous of Southern Italy and denoted by its particular rusticity. This study presents the preliminary results of the genetic characterization of the Podolica breed using DNA STR markers. A total of 20 microsatellite loci were analysed in 79 individuals reared in the Gargano area. Number of polymorphisms, allele fre- quencies, deviations from Hardy-Weinberg proportions, linkage disequilibrium between loci and genetic similarities between animals were calculated. The results showed a high deficiency of heterozygotes, the observed mean of het- erozygosis being 0.449, whereas the expected mean was 0.766. Many markers showed also deviations from the Hardy- Weinberg proportions and significant linkage disequilibrium between loci. However the genetic similarity within the pop- ulation was low (0.281 and the average number of alleles per locus was high (10, representing a high genetic vari- ability. In order to explain these results, a stratification of the breed in sub-populations with a high interior genetic homo- geneity but markedly differentiated one from each other could be hypothesized; this situation probably derived from non- random mating within each herd (consanguinity and from the lack of exchange of genetic material between the herds. A further study is needed on a wider sample and extending the analysis to FAO-ISAG microsatellite panel in order to con- firm this hypothesis. This could eventually provide the information necessary for the correct management of the repro- ductive schemes and for genomic traceability of meat production.

  4. RANS Analyses of Turbofan Nozzles with Internal Wedge Deflectors for Noise Reduction

    Science.gov (United States)

    DeBonis, James R.

    2009-01-01

    Computational fluid dynamics (CFD) was used to evaluate the flow field and thrust performance of a promising concept for reducing the noise at take-off of dual-stream turbofan nozzles. The concept, offset stream technology, reduces the jet noise observed on the ground by diverting (offsetting) a portion of the fan flow below the core flow, thickening and lengthening this layer between the high-velocity core flow and the ground observers. In this study a wedge placed in the internal fan stream is used as the diverter. Wind, a Reynolds averaged Navier-Stokes (RANS) code, was used to analyze the flow field of the exhaust plume and to calculate nozzle performance. Results showed that the wedge diverts all of the fan flow to the lower side of the nozzle, and the turbulent kinetic energy on the observer side of the nozzle is reduced. This reduction in turbulent kinetic energy should correspond to a reduction in noise. However, because all of the fan flow is diverted, the upper portion of the core flow is exposed to the freestream, and the turbulent kinetic energy on the upper side of the nozzle is increased, creating an unintended noise source. The blockage due to the wedge reduces the fan mass flow proportional to its blockage, and the overall thrust is consequently reduced. The CFD predictions are in very good agreement with experimental flow field data, demonstrating that RANS CFD can accurately predict the velocity and turbulent kinetic energy fields. While this initial design of a large scale wedge nozzle did not meet noise reduction or thrust goals, this study identified areas for improvement and demonstrated that RANS CFD can be used to improve the concept.

  5. Analysis of film cooling in rocket nozzles

    Science.gov (United States)

    Woodbury, Keith A.

    1992-01-01

    Computational Fluid Dynamics (CFD) programs are customarily used to compute details of a flow field, such as velocity fields or species concentrations. Generally they are not used to determine the resulting conditions at a solid boundary such as wall shear stress or heat flux. However, determination of this information should be within the capability of a CFD code, as the code supposedly contains appropriate models for these wall conditions. Before such predictions from CFD analyses can be accepted, the credibility of the CFD codes upon which they are based must be established. This report details the progress made in constructing a CFD model to predict the heat transfer to the wall in a film cooled rocket nozzle. Specifically, the objective of this work is to use the NASA code FDNS to predict the heat transfer which will occur during the upcoming hot-firing of the Pratt & Whitney 40K subscale nozzle (1Q93). Toward this end, an M = 3 wall jet is considered, and the resulting heat transfer to the wall is computed. The values are compared against experimental data available in Reference 1. Also, FDNS's ability to compute heat flux in a reacting flow will be determined by comparing the code's predictions against calorimeter data from the hot firing of a 40K combustor. The process of modeling the flow of combusting gases through the Pratt & Whitney 40K subscale combustor and nozzle is outlined. What follows in this report is a brief description of the FDNS code, with special emphasis on how it handles solid wall boundary conditions. The test cases and some FDNS solution are presented next, along with comparison to experimental data. The process of modeling the flow through a chamber and a nozzle using the FDNS code will also be outlined.

  6. Reactor vessel nozzle cracks: a photoelastic study

    International Nuclear Information System (INIS)

    Smith, C.W.

    1979-01-01

    A method consisting of a marriage between the ''frozen stress'' photoelastic approach and the local stress field equations of linear elastic fracture mechanics for estimating stress intensity factor distributions in three dimensional, finite cracked body problems is reviewed and extensions of the method are indicated. The method is then applied to the nuclear reactor vessel nozzle corner crack problem for both Intermediate Test Vessel and Boiling Water Reactor geometries. Results are compared with those of other investigators. 35 refs

  7. Nozzle flow calculation for real gases

    International Nuclear Information System (INIS)

    Bier, K.; Ehrler, F.; Hartz, U.; Kissau, G.

    1977-01-01

    The flow of CHF 2 Cl vapor (refrigerant R 22) through a Laval nozzle of annular geometry has been investigated in the region near the saturation line with stagnation pressures up to 85 per cent of the critical pressure. Static pressure profiles measured along the nozzle axis were found in good agreement with profiles calculated for one-dimensional isentropic flow of the real gas the thermal properties of which were derived from an equation of state proposed previously by Rombusch. Minor deviations between measured and calculated static pressure curves occur in the supersonic part of the mozzle, especially when supersaturated states of the vapour are passed. These deviations can be attributed to uncertainties in the calculation of the enthalpy and to a small influence of the static pressure probe. An additional investigation was concerned with an approximate calculation of the nozzle flow of real gases. In this approximation the well known relations of ideal gas dynamics are applied, the ratio of specific heats for the ideal gas being replaced, however, by a suitably adapted isentropic exponent, which can be determined e.g. from measured values of the Laval pressure or of the mass flow. For pressure ratios p/po between 1 and approximately 0.1, corresponding to Mach numbers up to approximately 2.2, all the interesting properties of the investigated flow of CHF 2 Cl vapour are approximated within a few per cent. (orig.) [de

  8. Coherent structures in a supersonic complex nozzle

    Science.gov (United States)

    Magstadt, Andrew; Berry, Matthew; Glauser, Mark

    2016-11-01

    The jet flow from a complex supersonic nozzle is studied through experimental measurements. The nozzle's geometry is motivated by future engine designs for high-performance civilian and military aircraft. This rectangular jet has a single plane of symmetry, an additional shear layer (referred to as a wall jet), and an aft deck representative of airframe integration. The core flow operates at a Mach number of Mj , c = 1 . 6 , and the wall jet is choked (Mj , w = 1 . 0). This high Reynolds number jet flow is comprised of intense turbulence levels, an intricate shock structure, shear and boundary layers, and powerful corner vortices. In the present study, stereo PIV measurements are simultaneously sampled with high-speed pressure measurements, which are embedded in the aft deck, and far-field acoustics in the anechoic chamber at Syracuse University. Time-resolved schlieren measurements have indicated the existence of strong flow events at high frequencies, at a Strouhal number of St = 3 . 4 . These appear to result from von Kàrmàn vortex shedding within the nozzle and pervade the entire flow and acoustic domain. Proper orthogonal decomposition is applied on the current data to identify coherent structures in the jet and study the influence of this vortex street. AFOSR Turbulence and Transition Program (Grant No. FA9550-15-1-0435) with program managers Dr. I. Leyva and Dr. R. Ponnappan.

  9. Head spray nozzle in reactor pressure vessel

    International Nuclear Information System (INIS)

    Hatano, Shun-ichi.

    1990-01-01

    In a reactor pressure vessel of a BWR type reactor, a head spray nozzle is used for cooling the head of the pressure vessel and, in view of the thermal stresses, it is desirable that cooling is applied as uniformly as possible. A conventional head spray is constituted by combining full cone type nozzles. Since the sprayed water is flown down upon water spraying and the sprayed water in the vertical direction is overlapped, the flow rate distribution has a high sharpness to form a shape as having a maximum value near the center and it is difficult to obtain a uniform flow rate distribution in the circumferential direction. Then, in the present invention, flat nozzles each having a spray water cross section of laterally long shape, having less sharpness in the circumferential distribution upon spraying water to the inner wall of the pressure vessel and having a wide angle of water spray are combined, to make the flow rate distribution of spray water uniform in the inner wall of the pressure vessel. Accordingly, the pressure vessel can be cooled uniformly and thermal stresses upon cooling can be decreased. (N.H.)

  10. Stress analysis of PCV nozzle junction

    International Nuclear Information System (INIS)

    Uchiyama, Shoichi; Oikawa, Tsuneo; Hoshino, Seizo

    1976-01-01

    Most of various pressure vessels comprise each one cylindrical shell and one or more nozzles. In this study, in order to analyze the stress in the structures of this type as minutely and exactly as possible, the program for stress analysis by the finite element method was made, which is required for the strength analysis for three-dimensional structures. Especially, the problem of the stress distribution around nozzle junctions was solved theoretically with the program. The program for the analysis developed in this study is provided with various functions, such as the input generator for cylindrical, conical and spherical shells, and plotter, and is very covenient. The accuracy of analysis is very good. The method of analysis and the calculation of the rigidity matrices for the deformation in plane and bending are explained. The result of the stress analysis around the nozzle junctions of a containment vessel with this program was in good agreement with experimental data and the result with SAP-4 code, therefore the propriety of the calculated result with this program was proved. Also calculations were carried out on three cases, namely a flat plate fixed at one end with distributed load, a cylinder fixed at one end with internal pressure, and an I-beam fixed at one end with concentrated load. The calculated results agreed well with theoretical solutions in all cases. (Kako, I.)

  11. Flow energy piezoelectric bimorph nozzle harvester

    Science.gov (United States)

    Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffrey L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro; Kim, Namhyo; Sun, Kai; Corbett, Gary

    2014-04-01

    There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

  12. Wintertime aerosol chemical composition, volatility, and spatial variability in the greater London area

    Directory of Open Access Journals (Sweden)

    L. Xu

    2016-02-01

    Full Text Available The composition of PM1 (particulate matter with diameter less than 1 µm in the greater London area was characterized during the Clean Air for London (ClearfLo project in winter 2012. Two high-resolution time-of-flight aerosol mass spectrometers (HR-ToF-AMS were deployed at a rural site (Detling, Kent and an urban site (North Kensington, London. The simultaneous and high-temporal resolution measurements at the two sites provide a unique opportunity to investigate the spatial distribution of PM1. We find that the organic aerosol (OA concentration is comparable between the rural and urban sites, but the contribution from different sources is distinctly different between the two sites. The concentration of solid fuel OA at the urban site is about twice as high as at the rural site, due to elevated domestic heating in the urban area. While the concentrations of oxygenated OA (OOA are well-correlated between the two sites, the OOA concentration at the rural site is almost twice that of the urban site. At the rural site, more than 70 % of the carbon in OOA is estimated to be non-fossil, which suggests that OOA is likely related to aged biomass burning considering the small amount of biogenic SOA in winter. Thus, it is possible that the biomass burning OA contributes a larger fraction of ambient OA in wintertime than what previous field studies have suggested. A suite of instruments was deployed downstream of a thermal denuder (TD to investigate the volatility of PM1 species at the rural Detling site. After heating at 250 °C in the TD, 40 % of the residual mass is OA, indicating the presence of non-volatile organics in the aerosol. Although the OA associated with refractory black carbon (rBC; measured by a soot-particle aerosol mass spectrometer only accounts for < 10 % of the total OA (measured by a HR-ToF-AMS at 250 °C, the two measurements are well-correlated, suggesting that the non-volatile organics have similar sources or have

  13. Seasonal variability of carbonaceous aerosols in an urban background area in Southern Italy

    Science.gov (United States)

    Cesari, D.; Merico, E.; Dinoi, A.; Marinoni, A.; Bonasoni, P.; Contini, D.

    2018-02-01

    Organic (OC) and Elemental Carbon (EC) are important components of atmospheric aerosol particles, playing a key role in climate system and potentially affecting human health. There is a lack of data reported for Southern Italy and this work aims to fill this gap, focusing the attention on the long-term trends of OC and EC concentrations in PM2.5 and PM10, and on atmospheric processes and sources influencing seasonal variability. Measurements were taken at the Environmental-Climate Observatory of Lecce (SE Italy, 40°20‧8″N-18°07‧28″E, 37 m a.s.l.), regional station of the Global Atmosphere Watch program (GAW-WMO). Daily PM10 and PM2.5 samples were collected between July 2013 and July 2016. In addition, starting in December 2014, simultaneous equivalent Black Carbon (eBC) concentrations in PM10 were measured using a Multi Angle Absorption Photometer. A subset of 722 PM samples (361 for each size fraction) was analysed by using a thermo-optical method with a Sunset Laboratory OC/EC analyser, to determine elemental and organic carbon concentrations. The average PM10 and PM2.5 concentrations were 28.8 μg/m3 and 17.5 μg/m3. The average OC and EC concentrations in PM10 were 5.4 μg/m3 and 0.8 μg/m3, in PM2.5 these were 4.7 μg/m3 and 0.6 μg/m3. Carbonaceous content was larger during cold season with respect to warm season as well as secondary organic carbon (SOC) that was evaluated using the OC/EC minimum ratio method. SOC was mainly segregated in PM2.5 and represented 53% - 75% of the total OC. A subset of EC data was compared with eBC measurements, showing a good correlation (R2 = 0.80), however, eBC concentrations were higher than EC concentrations of an average factor of 1.95 (+/- 0.55 standard deviation). This could be explained by the presence of a contribution of Brown Carbon (BrC), for example from biomass burning, in eBC measurements. Weekly patterns showed a slight decrease of carbon content during weekends with respect to weekdays especially

  14. Application of the vibration method for damage identification of a beam with a variable cross-sectional area

    Directory of Open Access Journals (Sweden)

    Zamorska Izabela

    2018-01-01

    Full Text Available The subject of the paper is an application of the non-destructive vibration method for identifying the location of two cracks occurring in a beam. The vibration method is based on knowledge of a certain number of vibration frequencies of an undamaged element and the knowledge of the same number of vibration frequencies of an element with a defect. The analyzed beam, with a variable cross-sectional area, has been described according to the Bernoulli-Euler theory. To determine the values of free vibration frequencies the analytical solution, with the help of the Green’s function method, has been used.

  15. Transient heating effects in high pressure Diesel injector nozzles

    International Nuclear Information System (INIS)

    Strotos, George; Koukouvinis, Phoevos; Theodorakakos, Andreas; Gavaises, Manolis; Bergeles, George

    2015-01-01

    Highlights: • Simulation of friction-induced heating in high pressure Diesel fuel injectors. • Injection pressures up to 3000 bar. • Simulations with variable fuel properties significantly affect predictions. • Needle motion affects flow and temperature fields. • Possible heterogeneous boiling as injection pressures increase above 2000 bar. - Abstract: The tendency of today’s fuel injection systems to reach injection pressures up to 3000 bar in order to meet forthcoming emission regulations may significantly increase liquid temperatures due to friction heating; this paper identifies numerically the importance of fuel pressurization, phase-change due to cavitation, wall heat transfer and needle valve motion on the fluid heating induced in high pressure Diesel fuel injectors. These parameters affect the nozzle discharge coefficient (C d ), fuel exit temperature, cavitation volume fraction and temperature distribution within the nozzle. Variable fuel properties, being a function of the local pressure and temperature are found necessary in order to simulate accurately the effects of depressurization and heating induced by friction forces. Comparison of CFD predictions against a 0-D thermodynamic model, indicates that although the mean exit temperature increase relative to the initial fuel temperature is proportional to (1 − C d 2 ) at fixed needle positions, it can significantly deviate from this value when the motion of the needle valve, controlling the opening and closing of the injection process, is taken into consideration. Increasing the inlet pressure from 2000 bar, which is the pressure utilized in today’s fuel systems to 3000 bar, results to significantly increased fluid temperatures above the boiling point of the Diesel fuel components and therefore regions of potential heterogeneous fuel boiling are identified

  16. Pengaruh Jarak dan Posisi Nozzle Terhadap Daya Turbin Pelton

    Directory of Open Access Journals (Sweden)

    Yani Kurniawan

    2017-12-01

    Full Text Available Pelton Turbine is a turbine which use nozzle as officers the direction of a stream water in order to move around of blade turbine. The rotating of turbine blade efected by some parameters such as the distance of the nozzle, position of nozzle, diameter of nozzle, number of nozzle, and the geometry shape of the blade turbine. An experimental study to analyze the affect of distance and position nozzle to Pelton Turbine of performance. The research method used experiment parameter was position of nozzle with three variations, first position is the right side horizontal of bottom shaft turbine, second position is vertical to down direction, and third position is the left side horizontal of upper shaft turbine. The parameter of nozzle distance used five variations was 24 cm, 23 cm, 22 cm, 21 cm, dan 20 cm, which measured from the end of position nozzle to blade turbine. The result shows that the right side horizontal of bottom shaft turbine with distance of nozzle 23 cm had the maximum performance to produce a power 125 Watt with the rotation of shaft turbine 263 rpm.

  17. Effect of chevron nozzle penetration on aero-acoustic characteristics of jet at M = 0.8

    Science.gov (United States)

    Nikam, S. R.; Sharma, S. D.

    2017-12-01

    Aero-acoustic characteristics of a high-speed jet with chevron nozzles are experimentally investigated at a Mach number of 0.8. The main focus is to examine the effects of the extent of chevron penetration and its position in the mixing layer. Chevron nozzles with three different levels of penetration employed at three different longitudinal locations from the nozzle lip are tested, and the results are compared with those of a plain baseline nozzle. The chevrons are found to produce a lobed shear layer through the notched region, thereby increasing the surface area of the jet, particularly in the close vicinity of the nozzle, which increases the mixing and reduces the potential core length. This effect becomes more prominent with increasing penetration closer to the nozzle lip in the thinner mixing layer. Near field and far field noise measurements show distinctly different acoustic features due to chevrons. The chevrons are found to effectively shift the dominant noise source upstream closer to the nozzle. Present investigation proposes a simpler method for locating the dominant noise source from the peak of the centerline velocity decay rate. The overall noise levels registered along the jet edge immediately downstream of the chevrons are higher, but further downstream they are reduced in comparison with the plain baseline nozzle. Also, the chevrons beam the noise towards higher polar angles at higher frequencies. At shallow polar angles with respect to the jet axis in the far field, chevrons suppress the noise at low frequencies with increasing penetration, but for higher polar angles, while they continue to suppress the low frequency noise, at higher frequencies the trend is found to reverse. The noise measured in the near field close to the jet edge is composed of two components: acoustic and hydrodynamic. Of these two components, the chevrons are found to reduce the hydrodynamic component in comparison with the acoustic one.

  18. Effect of chevron nozzle penetration on aero-acoustic characteristics of jet at M = 0.8

    Energy Technology Data Exchange (ETDEWEB)

    Nikam, S R [K. J. Somaiya college of Engineering, Mumbai (India); Sharma, S D, E-mail: srnikam12@gmail.com [I.I.T. Bombay, Mumbai (India)

    2017-12-15

    Aero-acoustic characteristics of a high-speed jet with chevron nozzles are experimentally investigated at a Mach number of 0.8. The main focus is to examine the effects of the extent of chevron penetration and its position in the mixing layer. Chevron nozzles with three different levels of penetration employed at three different longitudinal locations from the nozzle lip are tested, and the results are compared with those of a plain baseline nozzle. The chevrons are found to produce a lobed shear layer through the notched region, thereby increasing the surface area of the jet, particularly in the close vicinity of the nozzle, which increases the mixing and reduces the potential core length. This effect becomes more prominent with increasing penetration closer to the nozzle lip in the thinner mixing layer. Near field and far field noise measurements show distinctly different acoustic features due to chevrons. The chevrons are found to effectively shift the dominant noise source upstream closer to the nozzle. Present investigation proposes a simpler method for locating the dominant noise source from the peak of the centerline velocity decay rate. The overall noise levels registered along the jet edge immediately downstream of the chevrons are higher, but further downstream they are reduced in comparison with the plain baseline nozzle. Also, the chevrons beam the noise towards higher polar angles at higher frequencies. At shallow polar angles with respect to the jet axis in the far field, chevrons suppress the noise at low frequencies with increasing penetration, but for higher polar angles, while they continue to suppress the low frequency noise, at higher frequencies the trend is found to reverse. The noise measured in the near field close to the jet edge is composed of two components: acoustic and hydrodynamic. Of these two components, the chevrons are found to reduce the hydrodynamic component in comparison with the acoustic one. (paper)

  19. Seasonal variability of soil CO2 flux and its carbon isotope composition in Krakow urban area, Southern Poland.

    Science.gov (United States)

    Jasek, Alina; Zimnoch, Miroslaw; Gorczyca, Zbigniew; Smula, Ewa; Rozanski, Kazimierz

    2014-06-01

    As urban atmosphere is depleted of (13)CO2, its imprint should be detectable in the local vegetation and therefore in its CO2 respiratory emissions. This work was aimed at characterising strength and isotope signature of CO2 fluxes from soil in urban areas with varying distances from anthropogenic CO2 emissions. The soil CO2 flux and its δ(13)C isotope signature were measured using a chamber method on a monthly basis from July 2009 to May 2012 within the metropolitan area of Krakow, Southern Poland, at two locations representing different levels of anthropogenic influence: a lawn adjacent to a busy street (A) and an urban meadow (B). The small-scale spatial variability of the soil CO2 flux was also investigated at site B. Site B revealed significantly higher summer CO2 fluxes (by approximately 46 %) than site A, but no significant differences were found between their δ(13)CO2 signatures.

  20. Load calculation on the nozzle in a flue gas desulphurization system

    Science.gov (United States)

    Róbert, Olšiak; Zoltán, Fuszko; Zoltán, Csuka

    2017-09-01

    The desulphurization system is used to remove sulfur oxides from exhaust, so-called flue gases through absorbing them via the sprayed suspension. The suspension delivered from the pump system to the atmospheric bi-directional double hollow cone nozzle has the prescribed working pressure. The unknown mechanical load on the solid body of the nozzle is present through the change of moment due to the flow of the suspension through the bi-directional outflow areas [1], [4]. The calculation of the acting forces and torques in the 3 directions was carried out with the methods of computational fluid dynamics (CFD) in the software ANSYS Fluent. The geometric model of the flow areas of the nozzle were created with the methods of reverse engineering. The computational mesh required by the CFD solver was created, and its quality verified with the standard criteria. The used boundary conditions were defined by the hydraulic parameters of the pump system, the properties of the suspension present in the hydraulic system were specified by sample analysis. The post-processed and analyzed results of the CFD calculation, the pressure-field and the velocity magnitudes in particular directions were further used as input parameters at the mechanical analysis of the load on the bi-directional nozzle.

  1. Blood lead level in dogs from urban and rural areas of India and its relation to animal and environmental variables

    International Nuclear Information System (INIS)

    Balagangatharathilagar, M.; Swarup, D.; Patra, R.C.; Dwivedi, S.K.

    2006-01-01

    Lead is a common environmental pollutant with deleterious health effects on human and animal. Industrial and other human activities enhance the lead level in the environment leading to its higher residues in exposed population. The present study was aimed at determining blood lead concentration in dogs from two urban areas and in surrounding rural areas of India and analyzing lead level in dogs in relation to environmental (urban/ rural) and animal (age, sex, breed and housing) variables. Blood samples were collected from 305 dogs of either sex from urban (n = 277) and unpolluted rural localities (n = 28). Irrespective of breed, age and sex, the urban dogs had significantly (P < 0.01) higher mean blood lead concentration (0.25 ± 0.01 μg/ml) than rural dogs (0.10 ± 0.01 μg/ml). The mean blood lead level in stray dogs either from urban or rural locality (0.27 ± 0.01 μg/ml) was significantly (P < 0.01) higher than that of pets (0.20 ± 0.01 μg/ml), and the blood lead concentration was significantly higher in nondescript dogs (0.25 ± 0.01 μg/ml) than pedigreed dogs (0.20 ± 0.01 μg/ml). The locality (urban/rural) was the major variable affecting blood lead concentration in dogs. Breed and housing of the dogs of urban areas and only housing (pet/stray) in rural areas significantly (P < 0.01) influenced the blood lead concentration in dogs

  2. Synchronous multi-decadal climate variability of the whole Pacific areas revealed in tree rings since 1567

    Science.gov (United States)

    Fang, Keyan; Cook, Edward; Guo, Zhengtang; Chen, Deliang; Ou, Tinghai; Zhao, Yan

    2018-02-01

    Oceanic and atmospheric patterns play a crucial role in modulating climate variability from interannual to multi-decadal timescales by causing large-scale co-varying climate changes. The brevity of the existing instrumental records hinders the ability to recognize climate patterns before the industrial era, which can be alleviated using proxies. Unfortunately, proxy based reconstructions of oceanic and atmospheric modes of the past millennia often have modest agreements with each other before the instrumental period, raising questions about the robustness of the reconstructions. To ensure the stability of climate signals in proxy data through time, we first identified tree-ring datasets from distant regions containing coherent variations in Asia and North America, and then interpreted their climate information. We found that the multi-decadal covarying climate patterns of the middle and high latitudinal regions around the northern Pacific Ocean agreed quite well with the climate reconstructions of the tropical and southern Pacific areas. This indicates a synchronous variability at the multi-decadal timescale of the past 430 years for the entire Pacific Ocean. This pattern is closely linked to the dominant mode of the Pacific sea surface temperature (SST) after removing the warming trend. This Pacific multi-decadal SST variability resembles the Interdecadal Pacific Oscillation.

  3. Analysis of the Variability of Classified and Unclassified Radiological Source term Inventories in the Frenchman Flat Area, Nevada test Site

    International Nuclear Information System (INIS)

    Zhao, P.; Zavarin, M.

    2008-01-01

    It has been proposed that unclassified source terms used in the reactive transport modeling investigations at NTS CAUs should be based on yield-weighted source terms calculated using the average source term from Bowen et al. (2001) and the unclassified announced yields reported in DOE/NV-209. This unclassified inventory is likely to be used in unclassified contaminant boundary calculations and is, thus, relevant to compare to the classified inventory. They have examined the classified radionuclide inventory produced by 10 underground nuclear tests conducted in the Frenchman Flat (FF) area of the Nevada Test Site. The goals were to (1) evaluate the variability in classified radiological source terms among the 10 tests and (2) compare that variability and inventory uncertainties to an average unclassified inventory (e.g. Bowen 2001). To evaluate source term variability among the 10 tests, radiological inventories were compared on two relative scales: geometric mean and yield-weighted geometric mean. Furthermore, radiological inventories were either decay corrected to a common date (9/23/1992) or the time zero (t 0 ) of each test. Thus, a total of four data sets were produced. The date of 9/23/1992 was chosen based on the date of the last underground nuclear test at the Nevada Test Site

  4. Normalization of flow-mediated dilation to shear stress area under the curve eliminates the impact of variable hyperemic stimulus

    Directory of Open Access Journals (Sweden)

    Mickleborough Timothy D

    2008-09-01

    Full Text Available Abstract Background Normalization of brachial artery flow-mediated dilation (FMD to individual shear stress area under the curve (peak FMD:SSAUC ratio has recently been proposed as an approach to control for the large inter-subject variability in reactive hyperemia-induced shear stress; however, the adoption of this approach among researchers has been slow. The present study was designed to further examine the efficacy of FMD normalization to shear stress in reducing measurement variability. Methods Five different magnitudes of reactive hyperemia-induced shear stress were applied to 20 healthy, physically active young adults (25.3 ± 0. 6 yrs; 10 men, 10 women by manipulating forearm cuff occlusion duration: 1, 2, 3, 4, and 5 min, in a randomized order. A venous blood draw was performed for determination of baseline whole blood viscosity and hematocrit. The magnitude of occlusion-induced forearm ischemia was quantified by dual-wavelength near-infrared spectrometry (NIRS. Brachial artery diameters and velocities were obtained via high-resolution ultrasound. The SSAUC was individually calculated for the duration of time-to-peak dilation. Results One-way repeated measures ANOVA demonstrated distinct magnitudes of occlusion-induced ischemia (volume and peak, hyperemic shear stress, and peak FMD responses (all p AUC (p = 0.785. Conclusion Our data confirm that normalization of FMD to SSAUC eliminates the influences of variable shear stress and solidifies the utility of FMD:SSAUC ratio as an index of endothelial function.

  5. Using a topographic index to distribute variable source area runoff predicted with the SCS curve-number equation

    Science.gov (United States)

    Lyon, Steve W.; Walter, M. Todd; Gérard-Marchant, Pierre; Steenhuis, Tammo S.

    2004-10-01

    Because the traditional Soil Conservation Service curve-number (SCS-CN) approach continues to be used ubiquitously in water quality models, new application methods are needed that are consistent with variable source area (VSA) hydrological processes in the landscape. We developed and tested a distributed approach for applying the traditional SCS-CN equation to watersheds where VSA hydrology is a dominant process. Predicting the location of source areas is important for watershed planning because restricting potentially polluting activities from runoff source areas is fundamental to controlling non-point-source pollution. The method presented here used the traditional SCS-CN approach to predict runoff volume and spatial extent of saturated areas and a topographic index, like that used in TOPMODEL, to distribute runoff source areas through watersheds. The resulting distributed CN-VSA method was applied to two subwatersheds of the Delaware basin in the Catskill Mountains region of New York State and one watershed in south-eastern Australia to produce runoff-probability maps. Observed saturated area locations in the watersheds agreed with the distributed CN-VSA method. Results showed good agreement with those obtained from the previously validated soil moisture routing (SMR) model. When compared with the traditional SCS-CN method, the distributed CN-VSA method predicted a similar total volume of runoff, but vastly different locations of runoff generation. Thus, the distributed CN-VSA approach provides a physically based method that is simple enough to be incorporated into water quality models, and other tools that currently use the traditional SCS-CN method, while still adhering to the principles of VSA hydrology.

  6. Development of top nozzle for Korean standard LWR fuel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S. K.; Kim, I. K.; Choi, K. S.; Kim, Y. H.; Lee, J. N.; Kim, H. K. [KNFC, Taejon (Korea, Republic of)

    2001-10-01

    Performance evaluation was executed for each component and its assembly for the deduced Top Nozzles to develop the new Top Nozzle for LWR. This new Top Nozzle is composed of the optimum components among the derived Top Nozzles that have been evaluated in the viewpoint of structural integrity, simpleness of dismantle and assembly, manufacturability etc. In this study, the developed Top Nozzle satisfied all the related design criteria. In special, it makes fuel repair time reduced by assembling and disassembling itself as one body, and improves Fuel Assembly holddown ability by revising the design parameters of its spring and the structural integrity through the betterment of its geometrical shpae of Flange and Holddown Plate as compared with the existing LWR Top Nozzles.

  7. Mounting apparatus for a nozzle guide vane assembly

    Science.gov (United States)

    Boyd, Gary L.; Shaffer, James E.

    1995-01-01

    The present invention provides a ceramic nozzle guide assembly with an apparatus for mounting it to a metal nozzle case that includes an intermediate ceramic mounting ring. The mounting ring includes a plurality of projections that are received within a plurality of receptacles formed in the nozzle case. The projections of the mounting ring are secured within the receptacles by a ceramic retainer that allows contact between the two components only along arcuate surfaces thus eliminating sliding contact between the components.

  8. Fluidized-bed calciner with combustion nozzle and shroud

    International Nuclear Information System (INIS)

    Wielang, J.A.; Palmer, W.B.; Kerr, W.B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition. 4 claims, 2 figures

  9. Duoplasmatron with a nozzle type plasma expension cup

    International Nuclear Information System (INIS)

    Kobayashi, M.; Nishikawa, T.; Takagi, A.

    1974-01-01

    Various tests are described which were carried out in order to clarify the cause of the aberration existing in the beams extracted from a nozzle type plasma expansion cup. The tests involve the extraction electrodes having different edge shapes, gridded extraction electrodes, high-voltage facing electrodes at the cup exit making different angles with the axis, plasma cups having different contours at the exit, plasma cups gridded at the exit, biasing the cup exit with respect to anode, plasma cups having different ratios of the exit area to axial length, etc. The results show that the inward meniscus type distortion of the plasma boundary near the rim of plasma cup will be a dominant source for the aberration. Both proper shaping of the contour of the cup exit and biasing the cup exit reduced the aberration

  10. Research on and Design of a Self-Propelled Nozzle for the Tree-Type Drilling Technique in Underground Coal Mines

    Directory of Open Access Journals (Sweden)

    Yiyu Lu

    2015-12-01

    Full Text Available Due to the increasing depths of coal mines and the low permeability of some coal seams, conventional methods of gas drainage in underground mines are facing many problems. To improve gas extraction, a new technique using water jets to drill tree-type boreholes in coal seams is proposed. A self-propelled water-jet drilling nozzle was designed to drill these boreholes. The configuration of the self-propelled nozzle was optimized by conducting drilling experiments and self-propelling force measurements. Experimental results show that the optimal self-propelled nozzle has a forward orifice axial angle at 25°, a radial angle at 90°, a center distance of 1.5 mm, and backward pointing orifices with an axial angle of 25°. The self-propelling force generated by the jets of the nozzle with 30 MPa pump pressure can reach 29.8 N, enough to pull the hose and the nozzle forward without any external forces. The nozzle can drill at speeds up to 41.5 m/h with pump pressures at 30 MPa. The radial angles of the forward orifices improve the rock breaking performance of the nozzle and, with the correct angle, the rock breaking area of the orifices overlap to produce a connecting hole. The diameter of boreholes drilled by this nozzle can reach 35.2 mm. The nozzle design can be used as the basis for designing other self-propelled nozzles. The drilling experiments demonstrate the feasibility of using the tree-type drilling technique in underground mines.

  11. Analysis of Nozzle Jet Plume Effects on Sonic Boom Signature

    Science.gov (United States)

    Bui, Trong

    2010-01-01

    An axisymmetric full Navier-Stokes computational fluid dynamics (CFD) study was conducted to examine nozzle exhaust jet plume effects on the sonic boom signature of a supersonic aircraft. A simplified axisymmetric nozzle geometry, representative of the nozzle on the NASA Dryden NF-15B Lift and Nozzle Change Effects on Tail Shock (LaNCETS) research airplane, was considered. The highly underexpanded nozzle flow is found to provide significantly more reduction in the tail shock strength in the sonic boom N-wave pressure signature than perfectly expanded and overexpanded nozzle flows. A tail shock train in the sonic boom signature, similar to what was observed in the LaNCETS flight data, is observed for the highly underexpanded nozzle flow. The CFD results provide a detailed description of the nozzle flow physics involved in the LaNCETS nozzle at different nozzle expansion conditions and help in interpreting LaNCETS flight data as well as in the eventual CFD analysis of a full LaNCETS aircraft. The current study also provided important information on proper modeling of the LaNCETS aircraft nozzle. The primary objective of the current CFD research effort was to support the LaNCETS flight research data analysis effort by studying the detailed nozzle exhaust jet plume s imperfect expansion effects on the sonic boom signature of a supersonic aircraft. Figure 1 illustrates the primary flow physics present in the interaction between the exhaust jet plume shock and the sonic boom coming off of an axisymmetric body in supersonic flight. The steeper tail shock from highly expanded jet plume reduces the dip of the sonic boom N-wave signature. A structured finite-volume compressible full Navier-Stokes CFD code was used in the current study. This approach is not limited by the simplifying assumptions inherent in previous sonic boom analysis efforts. Also, this study was the first known jet plume sonic boom CFD study in which the full viscous nozzle flow field was modeled, without

  12. Experimental study of subsonic microjet escaping from a rectangular nozzle

    Science.gov (United States)

    Aniskin, V. M.; Maslov, A. A.; Mukhin, K. A.

    2016-10-01

    The first experiments on the subsonic laminar microjets escaping from the nozzles of rectangular shape are carried out. The nozzle size is 83.3x3823 microns. Reynolds number calculated by the nozzle height and the average flow velocity at the nozzle exit ranged from 58 to 154. The working gas was air at room temperature. The velocity decay and velocity fluctuations along the center line of the jet are determined. The fundamental difference between the laminar microjets characteristics and subsonic turbulent jets of macro size is shown. Based on measurements of velocity fluctuations it is shown the presence of laminar-turbulent transition in microjets and its location is determined.

  13. Heat and fluid flow properties of circular impinging jet with a low nozzle to plate spacing. Improvement by nothched nozzle; Nozzle heibankan kyori ga chiisai baai no enkei shototsu funryu no ryudo dennetsu tokusei. Kirikaki nozzle ni yoru kaizen kojo

    Energy Technology Data Exchange (ETDEWEB)

    Shakouchih, T. [Mie University, Mie (Japan). Faculty of Engineering; Matsumoto, A.; Watanabe, A.

    2000-10-25

    It is well known that as decreasing the nozzle to plate spacing considerably the heat transfer coefficient of circular impinging jet, which impinges to the plate normally, increases remarkably. At that time, the flow resistance of nozzle-plate system also increases rapidly. In this study, in order to reduce the flow resistance and to enhance the heat transfer coefficient of the circular impinging jet with a considerably low nozzle to plate spacing, a special nozzle with notches is proposed, and considerable improvement of the flow and heat transfer properties are shown. The mechanism of enhancement of the heat transfer properties is also discussed. (author)

  14. Digital Cover Photography for Estimating Leaf Area Index (LAI in Apple Trees Using a Variable Light Extinction Coefficient

    Directory of Open Access Journals (Sweden)

    Carlos Poblete-Echeverría

    2015-01-01

    Full Text Available Leaf area index (LAI is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io and transmitted radiation (I through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAID, which was compared with LAI estimated by the proposed digital photography method (LAIM. Results showed that the LAIM was able to estimate LAID with an error of 25% using a constant light extinction coefficient (k = 0.68. However, when k was estimated using an exponential function based on the fraction of foliage cover (ff derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  15. Variability of nutrients intake, lipid profile and cardiovascular mortality among geographical areas in Spain: The DRECE study.

    Science.gov (United States)

    Gómez de la Cámara, Agustín; De Andrés Esteban, Eva; Urrútia Cuchí, Gerard; Calderón Sandubete, Enrique; Rubio Herrera, Miguel Ángel; Menéndez Orenga, Miguel; Lora Pablos, David

    2017-11-07

    It has often been suggested that cardiovascular mortality and their geographical heterogeneity are associated with nutrients intake patterns and also lipid profile. The large Spanish study Dieta y Riesgo de Enfermedades Cardiovasculares en España (DRECE) investigated this theory from 1991 to 2010. Out of the 4,783 Spanish individuals making up the DRECE cohort, 220 subjects (148 men and 72 women) died (4.62%) during the course of the study. The mean age of patients who died from cardiovascular causes (32 in all) was 61.08 years 95% CI (57.47-64.69) and 70.91% of them were males. The consumption of nutrients and the lipid profile by geographical area, studied by geospatial models, showed that the east and southern area of the country had the highest fat intake coupled to a high rate of unhealthy lipid profile. It was concluded that the spatial geographical analysis showed a relationship between high fat intake, unhealthy lipid profile and cardiovascular mortality in the different geographical areas, with a high variability within the country.

  16. Digital cover photography for estimating leaf area index (LAI) in apple trees using a variable light extinction coefficient.

    Science.gov (United States)

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-28

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAI(D)), which was compared with LAI estimated by the proposed digital photography method (LAI(M)). Results showed that the LAI(M) was able to estimate LAI(D) with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (f(f)) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  17. Digital Cover Photography for Estimating Leaf Area Index (LAI) in Apple Trees Using a Variable Light Extinction Coefficient

    Science.gov (United States)

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-01

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAID), which was compared with LAI estimated by the proposed digital photography method (LAIM). Results showed that the LAIM was able to estimate LAID with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (ff) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions. PMID:25635411

  18. Static Internal Performance of a Two-Dimensional Convergent-Divergent Nozzle with External Shelf

    Science.gov (United States)

    Lamb, Milton; Taylor, John G.; Frassinelli, Mark C.

    1996-01-01

    An investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to determine the internal performance of a two-dimensional convergent-divergent nozzle. The nozzle design was tested with dry and afterburning throat areas, which represent different power settings and three expansion ratios. For each of these configurations, three trailing-edge geometries were tested. The baseline geometry had a straight trailing edge. Two different shaping techniques were applied to the baseline nozzle design to reduce radar observables: the scarfed design and the sawtooth design. A flat plate extended downstream of the lower divergent flap trailing edge parallel to the model centerline to form a shelf-like expansion surface. This shelf was designed to shield the plume from ground observation (infrared radiation (IR) signature suppression). The shelf represents the part of the aircraft structure that might be present in an installed configuration. These configurations were tested at nozzle pressure ratios from 2.0 to 12.0.

  19. Corrosion Damage in Penetration Nozzle and Its Weldment of Reactor Pressure Vessel Head

    International Nuclear Information System (INIS)

    Lim, Yun Soo; Kim, Joung Soo; Kim, Hong Pyo; Hwang, Seong Sik; Yi, Young Sun; Kim, Dong Jin; Jung, Man Kyo

    2003-07-01

    The recent status on corrosion damage of reactor vessel head (RVH) penetration nozzles at primary water reactors (PWRs), including control rod drive mechanism (CRDM) and thermocouple nozzles, was investigated. The studies for primary water stress corrosion cracking (PWSCC) characteristics of Alloy 600 and Alloy 182/82 were reviewed and summarized in terms of the crack initiation and crack growth rate. The studies on the boric acid corrosion (BAC) of low alloy steels were also included in this report. PWSCC was found to be the main failure mechanism of RVH CRDM nozzles, which are constituted with Alloy 600 base metal and Alloy 182 weld filler materials. Alloy 600 and Alloy 182/82 are very susceptible to intergranular SCC in the PWR environments. The PWSCC crack initiation and growth features in the fusion zone of Alloy 182/82 were strongly dependant on solidification anisotropy during welding, test temperature, weld heat, mechanical loading, stress relief heat treatment, cold work and so on. BAC of low alloy steels is a wastage phenomenon due to general corrosion occurring on the over-all surface area of material. Systematic studies, concerned with structural integrity of RVH penetration nozzles as well as improvement of PWSCC resistance of nickel-based weld metals in the simulated PWR environment, are needed

  20. BWR feedwater nozzle and control-rod-drive return line nozzle cracking

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    In its 1978 Annual Report to Congress, the Nuclear Regulatory Commission identified as an unresolved safety issue the appearance of cracks in feedwater nozzles at boiling-water reactors (BWRs). Later similar cracking, detected in return water lines for control-rod-drive systems at BWRs, was designated Part II of the issue. This article outlines the resolution of these cracking problems

  1. Nozzle evaluation for Project W-314

    International Nuclear Information System (INIS)

    Galbraith, J.D.

    1998-01-01

    Revisions to the waste transfer system piping to be implemented by Project W-314 will eliminate the need to access a majority of interfarm jumper connections associated with specific process pits. Additionally, connections that formerly facilitated waste transfers from the Plutonium-Uranium Extraction (PUREX) Plant are no longer required. This document identified unneeded process pit jumper connections, describes former designated routing, denotes current status (i.e., open or blanked), and recommends appropriate disposition for all. Blanking of identified nozzles should be accomplished by Project W-314 upon installation of jumpers and acceptance by Tank Waste Remediation System (TWRS) Tank Farm Operations

  2. Bottom nozzle of a LWR fuel assembly

    International Nuclear Information System (INIS)

    Leroux, J.C.

    1991-01-01

    The bottom nozzle consists of a transverse element in form of box having a bending resistant grid structure which has an outer peripheral frame of cross-section corresponding to that of the fuel assembly and which has walls defining large cells. The transverse element has a retainer plate with a regular array of openings. The retainer plate is fixed above and parallel to the grid structure with a spacing in order to form, between the grid structure and the retainer plate a free space for tranquil flow of cooling water and for debris collection [fr

  3. Airfoil shape for a turbine nozzle

    Science.gov (United States)

    Burdgick, Steven Sebastian; Patik, Joseph Francis; Itzel, Gary Michael

    2002-01-01

    A first-stage nozzle vane includes an airfoil having a profile according to Table I. The annulus profile of the hot gas path is defined in conjunction with the airfoil profile and the profile of the inner and outer walls by the Cartesian coordinate values given in Tables I and II, respectively. The airfoil is a three-dimensional bowed design, both in the airfoil body and in the trailing edge. The airfoil is steam and air-cooled by flowing cooling mediums through cavities extending in the vane between inner and outer walls.

  4. Study of nozzle deposit formation mechanism for direct injection gasoline engines; Chokufun gasoline engine yo nozzle no deposit seisei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, M; Saito, A [Toyota Central Research and Development Labs., Inc., Aichi (Japan); Matsushita, S [Toyota Motor Corp., Aichi (Japan); Shibata, H [Nippon Soken, Inc., Tokyo (Japan); Niwa, Y [Denso Corp., Aichi (Japan)

    1997-10-01

    Nozzles in fuel injectors for direct injection gasoline engines are exposed to high temperature combustion gases and soot. In such a rigorous environment, it is a fear that fuel flow rate changes in injectors by deposit formation on nozzles. Fundamental factors of nozzle deposit formation were investigated through injector bench tests and engine dynamometer tests. Deposit formation processes were observed by SEM through engine dynamometer tests. The investigation results reveal nozzle deposit formation mechanism and how to suppress the deposit. 4 refs., 8 figs., 3 tabs.

  5. Normalization of flow-mediated dilation to shear stress area under the curve eliminates the impact of variable hyperemic stimulus.

    Science.gov (United States)

    Padilla, Jaume; Johnson, Blair D; Newcomer, Sean C; Wilhite, Daniel P; Mickleborough, Timothy D; Fly, Alyce D; Mather, Kieren J; Wallace, Janet P

    2008-09-04

    Normalization of brachial artery flow-mediated dilation (FMD) to individual shear stress area under the curve (peak FMD:SSAUC ratio) has recently been proposed as an approach to control for the large inter-subject variability in reactive hyperemia-induced shear stress; however, the adoption of this approach among researchers has been slow. The present study was designed to further examine the efficacy of FMD normalization to shear stress in reducing measurement variability. Five different magnitudes of reactive hyperemia-induced shear stress were applied to 20 healthy, physically active young adults (25.3 +/- 0. 6 yrs; 10 men, 10 women) by manipulating forearm cuff occlusion duration: 1, 2, 3, 4, and 5 min, in a randomized order. A venous blood draw was performed for determination of baseline whole blood viscosity and hematocrit. The magnitude of occlusion-induced forearm ischemia was quantified by dual-wavelength near-infrared spectrometry (NIRS). Brachial artery diameters and velocities were obtained via high-resolution ultrasound. The SSAUC was individually calculated for the duration of time-to-peak dilation. One-way repeated measures ANOVA demonstrated distinct magnitudes of occlusion-induced ischemia (volume and peak), hyperemic shear stress, and peak FMD responses (all p index of endothelial function.

  6. EURCYL. A program to generate finite element meshes for pressure vessel nozzles

    International Nuclear Information System (INIS)

    De Windt, P.; Reynen, J.

    1974-12-01

    EURCYL is a program dealing with the automatic generation of finite element meshes for pressure vessel nozzles, using isoparametric elements with 8, 20 or 32 nodes. Options exist to generate BWR nozzles as well as PWR nozzles

  7. In service inspection of the reactor pressure vessel coolant and moderator nozzles at Atucha 1. 1998/1999 outages

    International Nuclear Information System (INIS)

    Antonaccio, Carlos; Conde, Alberto; Fittipaldi, Andres H.; Maniotti, Jorge; Moliterno, Gabriel E.

    2000-01-01

    During the August 1998 and the August 1999 Atucha 1 outages, two areas were inspected on the Reactor Pressure Vessel: the nozzle inner radii and the nozzle shell welds on all 3 moderator nozzles and all 4 main coolant nozzles. The inspections themselves were carried out by Mitsui Babcock Energy Limited from Scotland. The coordination, maintenance assistant and mounting of the manipulator devices over the nozzles were carried out by NASA personnel. Although it was not the first time the nozzle shell welds were inspected, due to the technologies advances in the ultrasonic field and in the inspection manipulators (magnetic ones), it was possible to inspect more volume than in previous inspections. In the other hand, it was the first time NASA was able to inspect the inner radii. In this last case the mayor problems to inspect them were the nozzles geometry and the small space available to install manipulators. The result of the inspections were: 1) There were no reportable indications at any of the inner radii inspected; 2) The inspection of nozzle to shell welds in main-coolant nozzles R3 and R4 detected flaws (one in each nozzle) which were reported as exceeding the dimensions specified as the acceptance level under Table IWB 3512-1, Section XI of the ASME code. Subsequent analysis requested by NASA and performed by Mitsui Babcock, demonstrated that the flaws were over dimensioned and could be explained as due to 'point' flaws. The analysis was based on theoretical mathematic model and experimental trials. Therefore their dimension were under the acceptance level of the ASME XI code. Although the Mitsui Babcock analysis, and at the same time it was in progress, it was assumed that the flaws were as they were originally presented (exceeding the acceptance level). NASA asked SIEMENS/KWU, the designer of the plant, to perform the fracture assessment according to ASME XI App. A. The assessment shows that the expected crack growth is negligibly small and the safety

  8. Analysis of film cooling in rocket nozzles

    Science.gov (United States)

    Woodbury, Keith A.

    1993-01-01

    This report summarizes the findings on the NASA contract NAG8-212, Task No. 3. The overall project consists of three tasks, all of which have been successfully completed. In addition, some supporting supplemental work, not required by the contract, has been performed and is documented herein. Task 1 involved the modification of the wall functions in the code FDNS (Finite Difference Navier-Stokes) to use a Reynolds Analogy-based method. This task was completed in August, 1992. Task 2 involved the verification of the code against experimentally available data. The data chosen for comparison was from an experiment involving the injection of helium from a wall jet. Results obtained in completing this task also show the sensitivity of the FDNS code to unknown conditions at the injection slot. This task was completed in September, 1992. Task 3 required the computation of the flow of hot exhaust gases through the P&W 40K subscale nozzle. Computations were performed both with and without film coolant injection. This task was completed in July, 1993. The FDNS program tends to overpredict heat fluxes, but, with suitable modeling of backside cooling, may give reasonable wall temperature predictions. For film cooling in the P&W 40K calorimeter subscale nozzle, the average wall temperature is reduced from 1750R to about 1050R by the film cooling. The average wall heat flux is reduced by a factor of 3.

  9. Characterization of soils in terms of pedological variability under different physiography of Damodar command area (part, West Bengal, India

    Directory of Open Access Journals (Sweden)

    Ranjan Bera

    2015-12-01

    Full Text Available Five representative soil profiles occurring on four different physiography under subtropical environment of Damodar command area, India, were studied for soil pedological variability. Two way approaches were taken to evaluate the extent of profile development. Firstly different extractants were used to determine various forms of Fe and Al and their different ratios. Average contents of Fe and Al, extracted by different extracting reagents were found to be in descending order, as follows: Aldith > Aloxa > Alpyr and Fedith > Feoxa > Fepyr. Analysis of pyrophosphate (pyr, oxalate (oxa, and dithionate (dith extractable Fe and Al fractions indicated that with increasing soil age, the content of crystalline Fe and Al oxides increased at the expense of the poorly crystalline forms. The mean content of amorphous Fe and Al, crystalline Fe and Al, and their ratios estimated the degree of soil development. In the second part, elemental analysis was done, silica to sesquioxide ratio as well as ratio of alkali cations was measured and weathering index of each horizon was determined. The ratios and weathering indices indicated that except Madhpur soil series, all other soils were young and pedological development was still in progress in Damodar command area.

  10. The Level of Psychological Burnout at the Teachers of Students with Autism Disorders in Light of a Number of Variables in Al-Riyadh Area

    Science.gov (United States)

    Atiyat, Omar Khalil

    2017-01-01

    This study aimed at measuring the level of the psychological burnout in the teachers of students that have autism symptoms in Al-Riyadh area--kingdom of Saudi Arabia. In light of variables. These variables are the gender, the teaching place, the academic qualification of the teachers, the experience of the teachers, the age of the teachers, and…

  11. Preliminary Two-Phase Terry Turbine Nozzle Models for RCIC Off-Design Operation Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haihua [Idaho National Lab. (INL), Idaho Falls, ID (United States); O' Brien, James [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-12

    This report presents the effort to extend the single-phase analytical Terry turbine model to cover two-phase off-design conditions. The work includes: (1) adding well-established two-phase choking models – the Isentropic Homogenous Equilibrium Model (IHEM) and Moody’s model, and (2) theoretical development and implementation of a two-phase nozzle expansion model. The two choking models provide bounding cases for the two-phase choking mass flow rate. The new two-phase Terry turbine model uses the choking models to calculate the mass flow rate, the critical pressure at the nozzle throat, and steam quality. In the divergent stage, we only consider the vapor phase with a similar model for the single-phase case by assuming that the liquid phase would slip along the wall with a much slower speed and will not contribute the impulse on the rotor. We also modify the stagnation conditions according to two-phase choking conditions at the throat and the cross-section areas for steam flow at the nozzle throat and at the nozzle exit. The new two-phase Terry turbine model was benchmarked with the same steam nozzle test as for the single-phase model. Better agreement with the experimental data is observed than from the single-phase model. We also repeated the Terry turbine nozzle benchmark work against the Sandia CFD simulation results with the two-phase model for the pure steam inlet nozzle case. The RCIC start-up tests were simulated and compared with the single-phase model. Similar results are obtained. Finally, we designed a new RCIC system test case to simulate the self-regulated Terry turbine behavior observed in Fukushima accidents. In this test, a period inlet condition for the steam quality varying from 1 to 0 is applied. For the high quality inlet period, the RCIC system behaves just like the normal operation condition with a high pump injection flow rate and a nominal steam release rate through the turbine, with the net addition of water to the primary system; for

  12. Grit blasting nozzle fabricated from mild tool steel proves satisfactory

    Science.gov (United States)

    Mc Farland, J. E.; Turbitt, B.

    1966-01-01

    Dry blasting with glass beads through a nozzle assembly descales both the outside and inside surfaces of tubes of Inconel 718 used for the distribution of gaseous oxygen. The inside of the nozzle is coated with polyurethane and the deflector with a commercially available liquid urethane rubber.

  13. Numerical analysis of choked converging nozzle flows with surface ...

    Indian Academy of Sciences (India)

    Choked converging nozzle flow and heat transfer characteristics are numerically investigated by means of a recent computational model that integrates the axisymmetric continuity, state, momentum and energy equations. To predict the combined effects of nozzle geometry, friction and heat transfer rates, analyses are ...

  14. Multi-orifice deposition nozzle for additive manufacturing

    Science.gov (United States)

    Lind, Randall F.; Post, Brian K.; Cini, Colin L.

    2017-11-21

    An additive manufacturing extrusion head includes a nozzle for accepting and depositing a heated material onto a work surface and/or part. The nozzle includes a valve body and an internal poppet body moveable between positions to permit deposition of at least two bead sizes of heated material onto a work surface and/or part.

  15. Noise from Aft Deck Exhaust Nozzles: Differences in Experimental Embodiments

    Science.gov (United States)

    Bridges, James E.

    2014-01-01

    Two embodiments of a rectangular nozzle on an aft deck are compared. In one embodiment the lower lip of the nozzle was extended with the sidewalls becoming triangles. In a second embodiment a rectangular nozzle was fitted with a surface that fit flush to the lower lip and extended outward from the sides of the nozzle, approximating a semi-infinite plane. For the purpose of scale-model testing, making the aft deck an integral part of the nozzle is possible for relatively short deck lengths, but a separate plate model is more flexible, accounts for the expanse of deck to the sides of the nozzle, and allows the nozzle to stand off from the deck. Both embodiments were tested and acoustic far-field results were compared. In both embodiments the extended deck introduces a new noise source, but the amplitude of the new source was dependent upon the span (cross-stream dimension) of the aft deck. The noise increased with deck length (streamwise dimension), and in the case of the beveled nozzle it increased with increasing aspect ratio. In previous studies of slot jets in wings it was noted that the increased noise from the extended aft deck appears as a dipole at the aft deck trailing edge, an acoustic source type with different dependence on velocity than jet mixing noise. The extraneous noise produced by the aft deck in the present studies also shows this behavior both in directivity and in velocity scaling.

  16. Combustor nozzle for a fuel-flexible combustion system

    Science.gov (United States)

    Haynes, Joel Meier [Niskayuna, NY; Mosbacher, David Matthew [Cohoes, NY; Janssen, Jonathan Sebastian [Troy, NY; Iyer, Venkatraman Ananthakrishnan [Mason, OH

    2011-03-22

    A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

  17. Ultrasonic pattern recognition study of feedwater nozzle inner radius indication

    International Nuclear Information System (INIS)

    Yoneyama, H.; Takama, S.; Kishigami, M.; Sasahara, T.; Ando, H.

    1983-01-01

    A study was made to distinguish defects on feed-water nozzle inner radius from noise echo caused by stainless steel cladding by using ultrasonic pattern recognition method with frequency analysis technique. Experiment has been successfully performed on flat clad plates and nozzle mock-up containing fatigue cracks and the following results which shows the high capability of frequency analysis technique are obtained

  18. Finite element analysis of inclined nozzle-plate junctions

    International Nuclear Information System (INIS)

    Dixit, K.B.; Seth, V.K.; Krishnan, A.; Ramamurthy, T.S.; Dattaguru, B.; Rao, A.K.

    1979-01-01

    Estimation of stress concentration at nozzle to plate or shell junctions is a significant problem in the stress analysis of nuclear reactors. The topic is a subject matter of extensive investigations and earlier considerable success has been reported on analysis for the cases when the nozzle is perpendicular to the plate or is radial to the shell. Analytical methods for the estimation of stress concentrations for the practical situations when the intersecting nozzle is inclined to the plate or is non-radial to the shell is rather scanty. Specific complications arise in dealing with the junction region when the nozzle with circular cross-section meets the non-circular cut-out on the plate or shell. In this paper a finite element analysis is developed for inclined nozzles and results are presented for nozzle-plate junctions. A method of analysis is developed with a view to achieving simultaneously accuracy of results and simplicity in the choice of elements and their connectivity. The circular nozzle is treated by axisymmetric conical shell elements. The nozzle portion in the region around the junction and the flat plate is dealt with by triangular flat shell elements. Special transition elements are developed for joining the flat shell elements with the axisymmetric elements under non-axisymmetric loading. A substructure method of analysis is adopted which achieves considerable economy in handling the structure and also conveniently combines the different types of elements in the structure. (orig.)

  19. Variability and climate change trend in vegetation phenology of recent decades in the Greater Khingan Mountain area, Northeastern China

    Directory of Open Access Journals (Sweden)

    Huan Tang

    2015-09-01

    Full Text Available Vegetation phenology has been used in studies as an indicator of an ecosystem’s responses to climate change. Satellite remote sensing techniques can capture changes in vegetation greenness, which can be used to estimate vegetation phenology. In this study, a long-term vegetation phenology study of the Greater Khingan Mountain area in Northeastern China was performed by using the Global Inventory Modeling and Mapping Studies (GIMMS normalized difference vegetation index version 3 (NDVI3g dataset from the years 1982–2012. After reconstructing the NDVI time series, the start date of the growing season (SOS, the end date of the growing season (EOS and the length of the growing season (LOS were extracted using a dynamic threshold method. The response of the variation in phenology with climatic factors was also analyzed. The results showed that the phenology in the study area changed significantly in the three decades between 1982 and 2012, including a 12.1-day increase in the entire region’s average LOS, a 3.3-day advance in the SOS and an 8.8-day delay in the EOS. However, differences existed between the steppe, forest and agricultural regions, with the LOSs of the steppe region, forest region and agricultural region increasing by 4.40 days, 10.42 days and 1.71 days, respectively, and a later EOS seemed to more strongly affect the extension of the growing season. Additionally, temperature and precipitation were closely correlated with the phenology variations. This study provides a useful understanding of the recent change in phenology and its variability in this high-latitude study area, and this study also details the responses of several ecosystems to climate change.

  20. Subscale Carbon-Carbon Nozzle Extension Development and Hot Fire Testing in Support of Upper Stage Liquid Rocket Engines

    Science.gov (United States)

    Gradl, Paul; Valentine, Peter; Crisanti, Matthew; Greene, Sandy Elam

    2016-01-01

    Upper stage and in-space liquid rocket engines are optimized for performance through the use of high area ratio nozzles to fully expand combustion gases to low exit pressures increasing exhaust velocities. Due to the large size of such nozzles and the related engine performance requirements, carbon-carbon (C/C) composite nozzle extensions are being considered for use in order to reduce weight impacts. NASA and industry partner Carbon-Carbon Advanced Technologies (C-CAT) are working towards advancing the technology readiness level of large-scale, domestically-fabricated, C/C nozzle extensions. These C/C extensions have the ability to reduce the overall costs of extensions relative to heritage metallic and composite extensions and to decrease weight by 50%. Material process and coating developments have advanced over the last several years, but hot fire testing to fully evaluate C/C nozzle extensions in relevant environments has been very limited. NASA and C-CAT have designed, fabricated and hot fire tested multiple subscale nozzle extension test articles of various C/C material systems, with the goal of assessing and advancing the manufacturability of these domestically producible materials as well as characterizing their performance when subjected to the typical environments found in a variety of liquid rocket and scramjet engines. Testing at the MSFC Test Stand 115 evaluated heritage and state-of-the-art C/C materials and coatings, demonstrating the capabilities of the high temperature materials and their fabrication methods. This paper discusses the design and fabrication of the 1.2k-lbf sized carbon-carbon nozzle extensions, provides an overview of the test campaign, presents results of the hot fire testing, and discusses potential follow-on development work.

  1. Study on steam pressure characteristics in various types of nozzles

    Science.gov (United States)

    Firman; Anshar, Muhammad

    2018-03-01

    Steam Jet Refrigeration (SJR) is one of the most widely applied technologies in the industry. The SJR system was utilizes residual steam from the steam generator and then flowed through the nozzle to a tank that was containing liquid. The nozzle converts the pressure energy into kinetic energy. Thus, it can evaporate the liquid briefly and release it to the condenser. The chilled water, was produced from the condenser, can be used to cool the product through a heat transfer process. This research aims to study the characteristics of vapor pressure in different types of nozzles using a simulation. The Simulation was performed using ANSYS FLUENT software for nozzle types such as convergent, convrgent-parallel, and convergent-divergent. The results of this study was presented the visualization of pressure in nozzles and was been validated with experiment data.

  2. TMI-2 instrument nozzle examinations at Argonne National Laboratory

    International Nuclear Information System (INIS)

    Neimark, L.A.; Shearer, T.L.; Purohit, A.; Hins, A.G.

    1993-09-01

    Six of the 14 instrument-penetration-tube nozzles removed from the lower head of TMI-2 were examined to identify damage mechanisms, provide insight to the fuel relocation scenario, and provide input data to the margin-to-failure analysis. Visual inspection, gamma scanning, metallography, microhardness measurements, and scanning electron microscopy were used to obtain the desired information. The results showed varying degrees of damage to the lower head nozzles, from ∼50% melt-off to no damage at all to near-neighbor nozzles. The elevations of nozzle damage suggested that the lower elevations (near the lower head) were protected from molten fuel, apparently by an insulating layer of fuel debris. The pattern of nozzle damage was consistent with fuel movement toward the hot-spot location identified in the vessel wall. Evidence was found for the existence of a significant quantity of control assembly debris on the lower head before the massive relocation of fuel occurred

  3. Top Nozzle Holddown Spring Optimization of KSNP Fuel Assembly

    International Nuclear Information System (INIS)

    Lee, Seong Ki; Park, Nam Kyu; Kim, Hyeong Koo; Lee, Joon Ro; Kim, Jae Won

    2002-01-01

    Nuclear fuel assembly for Korea Standard Nuclear Power (KSNP) Plant has 4 helical compression springs at the upper end of it. The springs, in conjunction with the fuel assembly weight, apply a holddown force against excess of buoyancy forces and the upward hydraulic forces due to the reactor coolant flow. Thus the holddown spring is to be designed such that the positive net downward force will be maintained for all normal and anticipated transient flow and temperature conditions in the nuclear reactor. With satisfying these in-reactor requirements of the fuel assembly holddown spring. Under the assumption that spring density is constant, the volume nozzle holddown spring. Under the assumption that spring density is constant, the volume minimization is executed by using the design variables, viz., wire diameter, mean coil diameter, minimization is executed by using the design variables, viz., wire diameter, mean coil diameter are within the compatible range of the fuel assembly structural components. Based on these conditions, the optimum design of the holddown spring is obtained considering the reactor operating condition and by using ANSYS code. The optimized spring has the properties that are a decreased volume and increased stiffness, compared with the existing one even if the absolute values are very similar each other. The holddown spring design features and the algorithm developed in this study could be directly applicable to the current commercial production. Therefore, it could be used to enhance the design efficiency and the functional performance of the spring, and to reduce a material cost a little

  4. Spatio-temporal variability of airborne bacterial communities and their correlation with particulate matter chemical composition across two urban areas.

    Science.gov (United States)

    Gandolfi, I; Bertolini, V; Bestetti, G; Ambrosini, R; Innocente, E; Rampazzo, G; Papacchini, M; Franzetti, A

    2015-06-01

    The study of spatio-temporal variability of airborne bacterial communities has recently gained importance due to the evidence that airborne bacteria are involved in atmospheric processes and can affect human health. In this work, we described the structure of airborne microbial communities in two urban areas (Milan and Venice, Northern Italy) through the sequencing, by the Illumina platform, of libraries containing the V5-V6 hypervariable regions of the 16S rRNA gene and estimated the abundance of airborne bacteria with quantitative PCR (qPCR). Airborne microbial communities were dominated by few taxa, particularly Burkholderiales and Actinomycetales, more abundant in colder seasons, and Chloroplasts, more abundant in warmer seasons. By partitioning the variation in bacterial community structure, we could assess that environmental and meteorological conditions, including variability between cities and seasons, were the major determinants of the observed variation in bacterial community structure, while chemical composition of atmospheric particulate matter (PM) had a minor contribution. Particularly, Ba, SO4 (2-) and Mg(2+) concentrations were significantly correlated with microbial community structure, but it was not possible to assess whether they simply co-varied with seasonal shifts of bacterial inputs to the atmosphere, or their variation favoured specific taxa. Both local sources of bacteria and atmospheric dispersal were involved in the assembling of airborne microbial communities, as suggested, to the one side by the large abundance of bacteria typical of lagoon environments (Rhodobacterales) observed in spring air samples from Venice and to the other by the significant effect of wind speed in shaping airborne bacterial communities at all sites.

  5. Novel design for transparent high-pressure fuel injector nozzles

    Science.gov (United States)

    Falgout, Z.; Linne, M.

    2016-08-01

    The efficiency and emissions of internal combustion (IC) engines are closely tied to the formation of the combustible air-fuel mixture. Direct-injection engines have become more common due to their increased practical flexibility and efficiency, and sprays dominate mixture formation in these engines. Spray formation, or rather the transition from a cylindrical liquid jet to a field of isolated droplets, is not completely understood. However, it is known that nozzle orifice flow and cavitation have an important effect on the formation of fuel injector sprays, even if the exact details of this effect remain unknown. A number of studies in recent years have used injectors with optically transparent nozzles (OTN) to allow observation of the nozzle orifice flow. Our goal in this work is to design various OTN concepts that mimic the flow inside commercial injector nozzles, at realistic fuel pressures, and yet still allow access to the very near nozzle region of the spray so that interior flow structure can be correlated with primary breakup dynamics. This goal has not been achieved until now because interior structures can be very complex, and the most appropriate optical materials are brittle and easily fractured by realistic fuel pressures. An OTN design that achieves realistic injection pressures and grants visual access to the interior flow and spray formation will be explained in detail. The design uses an acrylic nozzle, which is ideal for imaging the interior flow. This nozzle is supported from the outside with sapphire clamps, which reduces tensile stresses in the nozzle and increases the nozzle's injection pressure capacity. An ensemble of nozzles were mechanically tested to prove this design concept.

  6. Climate change, variability and extreme events : risk assessment and management strategies in a Peach cultivated area in Italy.

    Science.gov (United States)

    Alfieri, Silvia Maria; De Lorenzi, Francesca; Basile, Angelo; Bonfante, Antonello; Missere, Daniele; Menenti, Massimo

    2014-05-01

    Climate change in Mediterranean area is likely to reduce precipitation amounts and to increase temperature thus affecting the timing of development stages and the productivity of crops. Further, extreme weather events are expected to increase in the future leading to significant increase in agricultural risk. Some strategies for effectively managing risks and adapting to climate change involve adjustments to irrigation management and use of different varieties. We quantified the risk on Peach production in an irrigated area of "Emilia Romagna" region ( Italy) taking into account the impact on crop yield due to climate change and variability and to extreme weather events as well as the ability of the agricultural system to modulate this impact (adaptive capacity) through changes in water and crop management. We have focused on climatic events causing insufficient water supply to crops, while taking into account the effect of climate on the duration and timing of phenological stages. Further, extreme maximum and minimum temperature events causing significant reduction of crop yield have been considered using phase-specific critical temperatures. In our study risk was assessed as the product of the probability of a damaging event (hazard), such as drought or extreme temperatures, and the estimated impact of such an event (vulnerability). To estimate vulnerability we took into account the possible options to reduce risk, by combining estimates of the sensitivity of the system (negative impact on crop yield) and its adaptive capacity. The latter was evaluated as the relative improvement due to alternate management options: the use of alternate varieties or the changes in irrigation management. Vulnerability was quantified using cultivar-specific thermal and hydrologic requirements of a set of cultivars determined by experimental data and from scientific literature. Critical temperatures determining a certain reduction of crop yield have been estimated and used to assess

  7. The effect of orifice plate insertion on low NOx radial swirl burner performances (simulated variable area burner)

    International Nuclear Information System (INIS)

    Mohammad Nazri Mohd Jaafar

    2000-01-01

    The effect of inserting an outlet orifice plate of different sizes at the exit plane of the swirler outlet were studied for small radial swirler with fixed curves vanes. Tests were carried out using two different sizes flame tubes of 76 mm and 140 mm inside diameter, respectively and 330 mm in length. The system was fuelled via eight vane passage fuel nozzles of 3.5 mm diameter hole. This type of fuel injection helps in mixing the fuel and air better prior to ignition. Tests were carried out at 20 mm W.G. pressure loss which is representative of gas burners for domestic central heating system operating conditions. Tests were also carried out at 400 K preheated inlet air temperature and using only natural gas as fuel. The aim of the insertion of orifice plate was to create the swirler pressure loss at the swirler outlet phase so that the swirler outlet shear layer turbulence was maximize to assist with fuel/air mixing. For the present work, the smallest orifice plate exhibited a very low NO x emissions even at 0.7 equivalence ratio were NO x is well below 10 ppm corrected at 0% oxygen at dry basis. Other emissions such as carbon monoxide and unburned hydrocarbon were below 10 ppm and 100 ppm, respectively, over a wide range of operating equivalence ratios. The implies that good combustion was achieved using the smallest orifice plate. (Author)

  8. Inter-Annual Variability of Area-Scaled Gaseous Carbon Emissions from Wetland Soils in the Liaohe Delta, China.

    Science.gov (United States)

    Ye, Siyuan; Krauss, Ken W; Brix, Hans; Wei, Mengjie; Olsson, Linda; Yu, Xueyang; Ma, Xueying; Wang, Jin; Yuan, Hongming; Zhao, Guangming; Ding, Xigui; Moss, Rebecca F

    2016-01-01

    Global management of wetlands to suppress greenhouse gas (GHG) emissions, facilitate carbon (C) sequestration, and reduce atmospheric CO2 concentrations while simultaneously promoting agricultural gains is paramount. However, studies that relate variability in CO2 and CH4 emissions at large spatial scales are limited. We investigated three-year emissions of soil CO2 and CH4 from the primary wetland types of the Liaohe Delta, China, by focusing on a total wetland area of 3287 km2. One percent is Suaeda salsa, 24% is Phragmites australis, and 75% is rice. While S. salsa wetlands are under somewhat natural tidal influence, P. australis and rice are managed hydrologically for paper and food, respectively. Total C emissions from CO2 and CH4 from these wetland soils were 2.9 Tg C/year, ranging from 2.5 to 3.3 Tg C/year depending on the year assessed. Primary emissions were from CO2 (~98%). Photosynthetic uptake of CO2 would mitigate most of the soil CO2 emissions, but CH4 emissions would persist. Overall, CH4 fluxes were high when soil temperatures were >18°C and pore water salinity emissions from rice habitat alone in the Liaohe Delta represent 0.2% of CH4 carbon emissions globally from rice. With such a large area and interannual sensitivity in soil GHG fluxes, management practices in the Delta and similar wetlands around the world have the potential not only to influence local C budgeting, but also to influence global biogeochemical cycling.

  9. Predicting long-term streamflow variability in moist eucalypt forests using forest growth models and a sapwood area index

    Science.gov (United States)

    Jaskierniak, D.; Kuczera, G.; Benyon, R.

    2016-04-01

    A major challenge in surface hydrology involves predicting streamflow in ungauged catchments with heterogeneous vegetation and spatiotemporally varying evapotranspiration (ET) rates. We present a top-down approach for quantifying the influence of broad-scale changes in forest structure on ET and hence streamflow. Across three catchments between 18 and 100 km2 in size and with regenerating Eucalyptus regnans and E. delegatensis forest, we demonstrate how variation in ET can be mapped in space and over time using LiDAR data and commonly available forest inventory data. The model scales plot-level sapwood area (SA) to the catchment-level using basal area (BA) and tree stocking density (N) estimates in forest growth models. The SA estimates over a 69 year regeneration period are used in a relationship between SA and vegetation induced streamflow loss (L) to predict annual streamflow (Q) with annual rainfall (P) estimates. Without calibrating P, BA, N, SA, and L to Q data, we predict annual Q with R2 between 0.68 and 0.75 and Nash Sutcliffe efficiency (NSE) between 0.44 and 0.48. To remove bias, the model was extended to allow for runoff carry-over into the following year as well as minor correction to rainfall bias, which produced R2 values between 0.72 and 0.79, and NSE between 0.70 and 0.79. The model under-predicts streamflow during drought periods as it lacks representation of ecohydrological processes that reduce L with either reduced growth rates or rainfall interception during drought. Refining the relationship between sapwood thickness and forest inventory variables is likely to further improve results.

  10. A Basic Study on the Ejection of ICI Nozzle under Severe Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jong Rae; Bae, Ji Hoon; Bang, Kwang Hyun [Korea Maritime and Ocean University, Busan (Korea, Republic of); Park, Jong Woong [Dongguk University, Gyeongju (Korea, Republic of)

    2016-05-15

    Nozzle injection should be blocked because it affect to the environment if its melting core exposes outside. The purpose of this study is to carry out the thermos mechanical analysis due to debris relocation under severe accidents and to predict the nozzle ejection calculated considering the contact between the nozzle and lower head, and the supports of pipe cables. As a result of analyzing process of severe accidents, there was melting reaction between nozzle and the lower head. In this situation, we might predict the non-uniform contact region of nozzle hole of lower head and nozzle outside, delaying ejection of nozzles. But after melting, the average remaining length of the nozzle was 120mm and the maximum vertical displacement of lower nozzle near the weld is 3.3mm so there would be no nozzle this model, because the cable supports restrains the vertical displacement of nozzle.

  11. AeroPropulsoServoElasticity: Dynamic Modeling of the Variable Cycle Propulsion System

    Science.gov (United States)

    Kopasakis, George

    2012-01-01

    This presentation was made at the 2012 Fundamental Aeronautics Program Technical Conference and it covers research work for the Dynamic Modeling of the Variable cycle Propulsion System that was done under the Supersonics Project, in the area of AeroPropulsoServoElasticity. The presentation covers the objective for the propulsion system dynamic modeling work, followed by the work that has been done so far to model the variable Cycle Engine, modeling of the inlet, the nozzle, the modeling that has been done to model the affects of flow distortion, and finally presenting some concluding remarks and future plans.

  12. Specific decontamination methods: water nozzle, cavitation erosion

    International Nuclear Information System (INIS)

    Boulitrop, D.; Gauchon, J.P.; Lecoffre, Y.

    1984-05-01

    The erosion and decontamination tests carried out in the framework of this study, allowed to specify the fields favourable to the use of the high pressure jet taking into account the determinant parameters that are the pressure and the target-nozzle distance. The previous spraying of gels with chemical reagents (sulfuric acid anf hydrazine) allows to get better decontamination factors. Then, the feasibility study of a decontamination method by cavitation erosion is presented. Gelled compounds for decontamination have been developed; their decontamination quality has been evaluated by comparative contamination tests in laboratory and decontamination tests of samples of materials used in nuclear industry; this last method is adapted to remote handling devices and produces a low quantity of secondary effluents, so it allows to clean high contaminated installation on the site without additional exposure of the personnel [fr

  13. Feedback mechanism for smart nozzles and nebulizers

    Science.gov (United States)

    Montaser, Akbar [Potomac, MD; Jorabchi, Kaveh [Arlington, VA; Kahen, Kaveh [Kleinburg, CA

    2009-01-27

    Nozzles and nebulizers able to produce aerosol with optimum and reproducible quality based on feedback information obtained using laser imaging techniques. Two laser-based imaging techniques based on particle image velocimetry (PTV) and optical patternation map and contrast size and velocity distributions for indirect and direct pneumatic nebulizations in plasma spectrometry. Two pulses from thin laser sheet with known time difference illuminate droplets flow field. Charge coupled device (CCL)) captures scattering of laser light from droplets, providing two instantaneous particle images. Pointwise cross-correlation of corresponding images yields two-dimensional velocity map of aerosol velocity field. For droplet size distribution studies, solution is doped with fluorescent dye and both laser induced florescence (LIF) and Mie scattering images are captured simultaneously by two CCDs with the same field of view. Ratio of LIF/Mie images provides relative droplet size information, then scaled by point calibration method via phase Doppler particle analyzer.

  14. Noise Prediction Module for Offset Stream Nozzles

    Science.gov (United States)

    Henderson, Brenda S.

    2011-01-01

    A Modern Design of Experiments (MDOE) analysis of data acquired for an offset stream technology was presented. The data acquisition and concept development were funded under a Supersonics NRA NNX07AC62A awarded to Dimitri Papamoschou at University of California, Irvine. The technology involved the introduction of airfoils in the fan stream of a bypass ratio (BPR) two nozzle system operated at transonic exhaust speeds. The vanes deflected the fan stream relative to the core stream and resulted in reduced sideline noise for polar angles in the peak jet noise direction. Noise prediction models were developed for a range of vane configurations. The models interface with an existing ANOPP module and can be used or future system level studies.

  15. Variability and dilemmas in harm reduction for anabolic steroid users in the UK: a multi-area interview study

    Science.gov (United States)

    2014-01-01

    Background The UK continues to experience a rise in the number of anabolic steroid-using clients attending harm reduction services such as needle and syringe programmes. Methods The present study uses interviews conducted with harm reduction service providers as well as illicit users of anabolic steroids from different areas of England and Wales to explore harm reduction for this group of drug users, focussing on needle distribution policies and harm reduction interventions developed specifically for this population of drug users. Results The article addresses the complexity of harm reduction service delivery, highlighting different models of needle distribution, such as peer-led distribution networks, as well as interventions available in steroid clinics, including liver function testing of anabolic steroid users. Aside from providing insights into the function of interventions available to steroid users, along with principles adopted by service providers, the study found significant tensions and dilemmas in policy implementation due to differing perspectives between service providers and service users relating to practices, risks and effective interventions. Conclusion The overarching finding of the study was the tremendous variability across harm reduction delivery sites in terms of available measures and mode of operation. Further research into the effectiveness of different policies directed towards people who use anabolic steroids is critical to the development of harm reduction. PMID:24986546

  16. Spatial variability of the physical and mineralogical properties of the soil from the areas with variation in landscape shapes

    Directory of Open Access Journals (Sweden)

    Zigomar Menezes de Souza

    2009-04-01

    Full Text Available The objective of this work it was to use the geostatistics methods to investigate the spatial relationships between the physical and mineralogical properties of an oxisol planted with the sugarcane in an area of slight variations in the landform. The soil was sampled at 10 m regular intervals in the crossing points of a 100 x 100 m grid. At each point, the soil was collected at 0.0-0.2 m, 0.2-0.4 m and 0.4-0.6 m depths for the analyzes of physical properties and at 0.6-0.8 m for the mineralogical analyses. Both the Kt/Kt+Gb ratio and Kt relative crystallization level were higher in the compartment I than in the compartment II. As a consequence, the soil penetration resistance and bulk density were higher in the compartment I, while the macroporosity and Ksat were lower. Therefore, it was concluded that both the identification and mapping of a landform were efficient for understanding the spatial variability of the soil properties. Moreover, variations in the landscape shape promoted the differentiated variability of the physical and mineralogical soil properties: the more variable the landscape, the more variable was the soil properties.Este trabalho teve como objetivo avaliar a influência das formas do relevo na variabilidade espacial de atributos físicos e suas relações com a mineralogia da argila de um Latossolo Vermelho eutroférrico, utilizando a técnica da geoestatística. Os solos foram amostrados nos pontos de cruzamento de uma malha, com intervalos regulares de 10 m, nas profundidades de 0,0-0,2 m, 0,2-0,4 m e 0,4-0,6 m para os atributos físicos e 0,6-0,8 m para os atributos mineralógicos. Os valores médios para a densidade do solo e resistência do solo à penetração são maiores no compartimento I onde a relação Ct/Ct+Gb é relativamente maior, indicando a presença de maior teor de caulinita. No compartimento II a condutividade hidráulica e a macroporsidade são maiores, influenciados provavelmente pelo predomínio da

  17. Flame Interactions and Thermoacoustics in Multiple-Nozzle Combustors

    Science.gov (United States)

    Dolan, Brian

    The first major chapter of original research (Chapter 3) examines thermoacoustic oscillations in a low-emission staged multiple-nozzle lean direct injection (MLDI) combustor. This experimental program investigated a relatively practical combustor sector that was designed and built as part of a commercial development program. The research questions are both practical, such as under what conditions the combustor can be safely operated, and fundamental, including what is most significant to driving the combustion oscillations in this system. A comprehensive survey of operating conditions finds that the low-emission (and low-stability) intermediate and outer stages are necessary to drive significant thermoacoustics. Phase-averaged and time-resolved OH* imaging show that dramatic periodic strengthening and weakening of the reaction zone downstream of the low-emission combustion stages. An acoustic modal analysis shows the pressure wave shapes and identifies the dominant thermoacoustic behavior as the first longitudinal mode for this combustor geometry. Finally, a discussion of the likely significant coupling mechanisms is given. Periodic reaction zone behavior in the low-emission fuel stages is the primary contributor to unsteady heat release. Differences between the fuel stages in the air swirler design, the fuel number of the injectors, the lean blowout point, and the nominal operating conditions all likely contribute to the limit cycle behavior of the low-emission stages. Chapter 4 investigates the effects of interaction between two adjacent swirl-stabilized nozzles using experimental and numerical tools. These studies are more fundamental; while the nozzle hardware is the same as the lean direct injection nozzles used in the MLDI combustion concept, the findings are generally applicable to other swirl-stabilized combustion systems as well. Much of the work utilizes a new experiment where the distance between nozzles was varied to change the level of interaction

  18. Effect of the nozzle tip’s geometrical shape on electrospray deposition of organic thin films

    Science.gov (United States)

    Ueda, Hiroyuki; Takeuchi, Keita; Kikuchi, Akihiko

    2017-04-01

    Electrospray deposition (ESD) is a favorable wet fabrication technique for organic thin films. We investigated the effects of the nozzle tip’s geometrical shape on the spraying properties of an organic solution used for ESD. Five types of cylindrical metal nozzles with zero (flat end) to four protrusions at the tips were prepared for depositing a solution of a small-molecule compound, tris(8-hydroxyquinolinato)aluminum (Alq3) solution. We confirmed that the diameter of the deposited droplets and their size dispersion decreased with an increase in the number of protrusions. The area occupation ratio of small droplets with a diameter smaller than 2 µm increased from 21 to 83% as the number of protrusions was increased from zero to four. The surface roughness root mean square of 60-nm-thick Alq3 films substantially improved from 32.5 to 6.8 nm with increasing number of protrusions.

  19. Wind tunnel measurement of spray drift from on-off controlled sprayer nozzles

    DEFF Research Database (Denmark)

    Lund, Ivar; Jensen, Peter Kryger; Miller, Paul

    wide surface area with a length of 200 mm. The test was conducted in the wind tunnel at Silsoe Spray Applications Unit in the UK. The measurements consisted of two test series; airborne drift was collected on polyethylene lines more than 375 mm away from the centerline of the nozzle and ground deposits...... and arranged to deliver a pulse of spray using the WeedSeeker valve. The tests were conducted to determine accumulated spray deposit at different crosswind and forward speeds. In general, the deposits, especially those measured downwind close to the target zone showed significant increase as the crosswind......Sensor-based precision weed control system at a high resolution requires a high spray application accuracy to keep the spray in a small target zone. The objective of this research was to investigate the target accuracy and spray drift from individual controlled sprayer nozzles targeting a 250 mm...

  20. Fuel injector nozzle for an internal combustion engine

    Science.gov (United States)

    Cavanagh, Mark S.; Urven, Jr., Roger L.; Lawrence, Keith E.

    2008-11-04

    A direct injection fuel injector includes a nozzle tip having a plurality of passages allowing fluid communication between an inner nozzle tip surface portion and an outer nozzle tip surface portion and directly into a combustion chamber of an internal combustion engine. A first group of the passages have inner surface apertures located substantially in a first common plane. A second group of the passages have inner surface apertures located substantially in at least a second common plane substantially parallel to the first common plane. The second group has more passages than the first group.

  1. The fabrication of nozzles for nuclear components by welding

    International Nuclear Information System (INIS)

    Moraes, M.M.; Krausser, P.; Echeverria, J.A.V.

    1986-01-01

    A nozzle with medium outside diameter of 1000 mm and medium thickness of 150 mm composed integrally by deposited metal by submerged-arc (wire S3NiMo1, 0.5mm) was fabricated in NUCLEP. The nondestructive, mechanical, metallographic and chemical testing carried out in a test sample made by the same procedure and welding parameters, showed results according to specifications established for primary components for nuclear power plants, and the tests presented mechanical properties and tenacity better than similar nozzle samples. This nozzle is cheapest concerning to importations, in respecting to its forged similar. (M.C.K.) [pt

  2. Study of an ejector-absorption refrigeration cycle with an adaptable ejector nozzle for different working conditions

    International Nuclear Information System (INIS)

    Vereda, C.; Ventas, R.; Lecuona, A.; Venegas, M.

    2012-01-01

    Highlights: ► An absorption refrigeration cycle with an ejector device at the absorber inlet is presented. ► This cycle is able to reduce up to 9 °C the temperature of onset of refrigerant generation without extra energy consumption. ► At very low driving temperatures it allows increasing the cooling capacity. ► The ejector device proposed has a partially variable geometry and we study its influence on the cycle performances. -- Abstract: This paper presents a numerical model of an ejector-absorption (single-effect) refrigeration cycle with ammonia–lithium nitrate solution as working fluid, operating under steady-state conditions. In this cycle, the ejector is located at the absorber inlet replacing the solution expansion valve. The liquid–gas ejector entrains refrigerant vapor from the evaporator; this way the absorber pressure becomes higher than the evaporator pressure without any additional energy consumption. The objective of this numerical model is to evaluate the influence of the ejector geometry on the cycle performances and to determine the range of the heat source temperature in which it is convenient to use a practical ejector in the absorption cycle. The simulation is based on UA-ΔT lm models for separate heat transfer regions in a novel implementation using plate-type heat exchangers and this way the results are offered as a function of the external temperatures. This study focuses on evaluating the feasibility of an ejector whose nozzle area is adjustable while the rest of the ejector dimensions are fixed, thus being more feasible than complete variable geometry ejectors. The cycle performance is reported for different mixing tube constant diameters. Results of the simulation show that the use of an ejector allows, among others, to decrease the activation temperature approximately 9 °C in respect to the conventional single-effect absorption cycle and increasing the COP for moderate temperatures. The variable ejector nozzle geometry is

  3. Variability of cannabis potency in the Venice area (Italy): a survey over the period 2010-2012.

    Science.gov (United States)

    Zamengo, Luca; Frison, Giampietro; Bettin, Chiara; Sciarrone, Rocco

    2014-01-01

    Cannabis is the most widely used illicit substance globally, with an estimated annual prevalence in 2010 of 2.6-5.0% of the adult population. Concerns have been expressed about increases in the potency of cannabis products. A high tetrahydrocannabinol (THC) content can increase anxiety, depression, and psychotic symptoms, and can increase the risk of dependence and adverse effects on the respiratory and cardiovascular systems in regular users. The aim of this study was to report statistical data about the potency of cannabis products seized in the north-east of Italy, in a geographical area centred in Venice and extending for more than 10,000  km(2) with a population of more than two million, by investigating the variability observed in THC levels of about 4000 samples of cannabis products analyzed over the period 2010-2012. Overall median THC content showed an increasing trend over the study period from about 6.0% to 8.1% (6.2-8.9% for cannabis resin, 5.1-7.6% for herbal cannabis). The variation in the THC content of individual samples was very large, ranging from 0.3% to 31% for cannabis resin and from 0.1 to 19% for herbal cannabis. Median CBN:THC ratios showed a slightly decreasing trend over the study period, from 0.09 (2010) to 0.03 (2012), suggesting an increasing freshness of submitted materials. Median CBD:THC ratios also showed a decreasing trend over the study from about 0.52 (2010) to 0.18 (2012), likely due to the increase in submissions of materials from indoor and domestic cultivation with improved breeding methods. Copyright © 2013 John Wiley & Sons, Ltd.

  4. Genetic variability of Rickettsia spp. in Ixodes persulcatus ticks from continental and island areas of the Russian Far East.

    Science.gov (United States)

    Igolkina, Y; Bondarenko, E; Rar, V; Epikhina, T; Vysochina, N; Pukhovskaya, N; Tikunov, A; Ivanov, L; Golovljova, I; Ivanov, М; Tikunova, N

    2016-10-01

    Rickettsia spp. are intracellular Gram-negative bacteria transmitted by arthropods. Two potentially pathogenic rickettsiae, Candidatus Rickettsia tarasevichiae and Rickettsia helvetica, have been found in unfed adult Ixodes persulcatus ticks. The aim of this study was to assess the prevalence and genetic variability of Rickettsia spp. in I. persulcatus ticks collected from different locations in the Russian Far East. In total, 604 adult I. persulcatus ticks collected from four sites in the Khabarovsk Territory (continental area) and one site in Sakhalin Island were examined for the presence of Rickettsia spp. by real-time PCR. Nested PCR with species-specific primers and sequencing were used for genotyping of revealed rickettsiae. The overall prevalence of Rickettsia spp. in ticks collected in different sites varied from 67.9 to 90.7%. However, the proportion of different Rickettsia species observed in ticks from Sakhalin Island significantly differed from that in ticks from the Khabarovsk Territory. In Sakhalin Island, R. helvetica prevailed in examined ticks, while Candidatus R. tarasevichiae was predominant in the Khabarovsk Territory. For gltA and ompB gene fragments, the sequences obtained for Candidatus R. tarasevichiae from all studied sites were identical to each other and to the known sequences of this species. According to sequence analysis of gltA, оmpB and sca4 genes, R. helvetica isolates from Sakhalin Island and the Khabarovsk Territory were identical to each other, but they differed from R. helvetica from other regions and from those found in other tick species. For the first time, DNA of pathogenic Rickettsia heilongjiangensis was detected in I. persulcatus ticks in two sites from the Khabarovsk Territory. The gltA, ompA and оmpB gene sequences of R. heilongjiangensis were identical to or had solitary mismatches with the corresponding sequences of R. heilongjiangensis found in other tick species. Copyright © 2016 Elsevier GmbH. All rights

  5. Altitude Compensating Nozzle Transonic Performance Flight Demonstration, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Altitude compensating nozzles continue to be of interest for use on future launch vehicle boosters and upper stages because of their higher mission average Isp and...

  6. Design methods of Coanda effect nozzle with two streams

    Directory of Open Access Journals (Sweden)

    Michele TRANCOSSI

    2014-03-01

    Full Text Available This paper continues recent research of the authors about the ACHEON Coanda effect two streams nozzle. This nozzle aims to produce an effective deflection of a propulsive jet with a correspondent deviation of the thrust vector in a 2D plane. On the basis of a previously published mathematical model, based on integral equations, it tries to produce an effective design guideline, which can be adopted for design activities of the nozzle for aeronautic propulsion. The presented model allows defining a governing method for this innovative two stream synthetic jet nozzle. The uncertainness level of the model are discussed and novel aircraft architectures based on it are presented. A CFD validation campaign is produced focusing on validating the model and the designs produced.

  7. Characterization of Plasmadynamics within a Small Magnetic Nozzle

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal presents an experimental and theoretical research project intended to develop a more refined model of the underlying physics of magnetic nozzles. The...

  8. Separation of a light additive gas by separation nozzle cascades

    International Nuclear Information System (INIS)

    Becker, E.; Bley, P.; Ehrfeld, W.; Fritz, W.; Steinhaus, H.

    1984-01-01

    Double-turn separation nozzles, in comparison with single-turn separation nozzles, offer much greater advantages in the separation of UF6 and H2 than in the separation of the U isotopes, for which the double-turn separation nozzles were conceived. By using a double-turn separation-nozzle stage as a preseparation stage in combination with a low-temperature separator, one can reduce the ratio of the buffer input stream to the product stream, in contrast with the solution used up to this time, with only a slight increase in cost of about an order of magnitude. The control program in the case of return feeding of the UF6 from the buffer and the danger of production losses connected with it are thereby correspondingly diminished. An example is given of the enrichment of 235U using the title facility with UF6. (orig./PW)

  9. Optimal Thrust Vectoring for an Annular Aerospike Nozzle, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  10. Effects of injection nozzle exit width on rotating detonation engine

    Science.gov (United States)

    Sun, Jian; Zhou, Jin; Liu, Shijie; Lin, Zhiyong; Cai, Jianhua

    2017-11-01

    A series of numerical simulations of RDE modeling real injection nozzles with different exit widths are performed in this paper. The effects of nozzle exit width on chamber inlet state, plenum flowfield and detonation propagation are analyzed. The results are compared with that using an ideal injection model. Although the ideal injection model is a good approximation method to model RDE inlet, the two-dimensional effects of real nozzles are ignored in the ideal injection model so that some complicated phenomena such as the reflected waves caused by the nozzle walls and the reversed flow into the nozzles can not be modeled accurately. Additionally, the ideal injection model overpredicts the block ratio. In all the cases that stabilize at one-wave mode, the block ratio increases as the nozzle exit width gets smaller. The dual-wave mode case also has a relatively high block ratio. A pressure oscillation in the plenum with the same main frequency with the rotating detonation wave is observed. A parameter σ is applied to describe the non-uniformity in the plenum. σ increases as the nozzle exit width gets larger. Under some condition, the heat release on the interface of fresh premixed gas layer and detonation products can be strong enough to induce a new detonation wave. A spontaneous mode-transition process is observed for the smallest exit width case. Due to the detonation products existing in the premixed gas layer before the detonation wave, the detonation wave will propagate through reactants and products alternately, and therefore its strength will vary with time, especially near the chamber inlet. This tendency gets weaker as the injection nozzle exit width increases.

  11. Study of Liquid Breakup Process in Solid Rocket Motor Nozzle

    Science.gov (United States)

    2016-02-16

    Laboratory, Edwards, CA Abstract In a solid rocket motor (SRM), when the aluminum based propellant combusts, the fuel is oxidized into alumina (Al2O3...34Chemical Erosion of Refractory-Metal Nozzle Inserts in Solid - Propellant Rocket Motors," J. Propulsion and Power, Vol. 25, no.1,, 2009. [4] E. Y. Wong...34 Solid Rocket Nozzle Design Summary," in 4th AIAA Propulsion Joint Specialist Conference, Cleveland, OH, 1968. [5] Nayfeh, A. H.; Saric, W. S

  12. Nozzle Mounting Method Optimization Based on Robot Kinematic Analysis

    Science.gov (United States)

    Chen, Chaoyue; Liao, Hanlin; Montavon, Ghislain; Deng, Sihao

    2016-08-01

    Nowadays, the application of industrial robots in thermal spray is gaining more and more importance. A desired coating quality depends on factors such as a balanced robot performance, a uniform scanning trajectory and stable parameters (e.g. nozzle speed, scanning step, spray angle, standoff distance). These factors also affect the mass and heat transfer as well as the coating formation. Thus, the kinematic optimization of all these aspects plays a key role in order to obtain an optimal coating quality. In this study, the robot performance was optimized from the aspect of nozzle mounting on the robot. An optimized nozzle mounting for a type F4 nozzle was designed, based on the conventional mounting method from the point of view of robot kinematics validated on a virtual robot. Robot kinematic parameters were obtained from the simulation by offline programming software and analyzed by statistical methods. The energy consumptions of different nozzle mounting methods were also compared. The results showed that it was possible to reasonably assign the amount of robot motion to each axis during the process, so achieving a constant nozzle speed. Thus, it is possible optimize robot performance and to economize robot energy.

  13. Stresses in reactor pressure vessel nozzles -- Calculations and experiments

    International Nuclear Information System (INIS)

    Brumovsky, M.; Polachova, H.

    1995-01-01

    Reactor pressure vessel nozzles are characterized by a high stress concentration which is critical in their low-cycle fatigue assessment. Program of experimental verification of stress/strain field distribution during elastic-plastic loading of a reactor pressure vessel WWER-1000 primary nozzle model in scale 1:3 is presented. While primary nozzle has an ID equal to 850 mm, the model nozzle has ID equal to 280 mm, and was made from 15Kh2NMFA type of steel. Calculation using analytical methods was performed. Comparison of results using different analytical methods -- Neuber's, Hardrath-Ohman's as well as equivalent energy ones, used in different reactor Codes -- is shown. Experimental verification was carried out on model nozzles loaded statically as well as by repeated loading, both in elastic-plastic region. Strain fields were measured using high-strain gauges, which were located in different distances from center of nozzle radius, thus different stress concentration values were reached. Comparison of calculated and experimental data are shown and compared

  14. Effect of nozzle arrangement on Venturi scrubber performance

    Energy Technology Data Exchange (ETDEWEB)

    Ananthanarayanan, N.V.; Viswanathan, S.

    1999-12-01

    The effect of nozzle arrangement on flux distribution is studied in a rectangular, pilot-scale, Pease-Anthony-type Venturi scrubber. The annular, two-phase, heterogeneous, three-dimensional gas-liquid flow inside the scrubber is modeled using a commercial computational fluid dynamic (CFD) package, FLUENT. The comparison of predicted liquid drop concentration shows good agreement with experimental data. The model predicts the fraction of liquid flowing as film on the walls reasonably well. Visualization of flux patterns studied using four typical nozzle configurations indicate that the nonuniformity in flux distribution increases when the nozzle-to-nozzle distance is greater than 10% of the width of the side on which the nozzles are placed. An analysis of the effect of multiple jet penetration lengths on liquid flux distribution yielded a comparable distribution at 10--45% less liquid than uniform penetration for a particular nozzle configuration. This would lead to significant improvements in scrubber performance by achieving comparable collection efficiency at a lower pressure drop.

  15. Reverse flow through a large scale multichannel nozzle

    International Nuclear Information System (INIS)

    Duignan, M.R.; Nash, C.A.

    1992-01-01

    A database was developed for the flow of water through a scaled nozzle of a Savannah River Site reactor inlet plenum. The water flow in the nozzle was such that it ranged from stratified to water solid conditions. Data on the entry of air into the nozzle and plenum as a function of water flow are of interest in loss-of-coolant studies. The scaled nozzle was 44 cm long, had an entrance diameter of 95 mm, an exit opening of 58 mm x 356 mm, and an exit hydraulic diameter approximately equal to that of the inlet. Within the nozzle were three flow-straightening vanes which divided the flow path into four channels. All data were taken at steady-state and isothermal (300 K ± 1.5 K) conditions. During the reverse flow of water through the nozzle the point at which air begins to enter was predicted within 90% by a critical weir-flow calculation. The point of air entry into the plenum itself was found to be a function of flow conditions

  16. Remedial measures for nozzles susceptible to PWSCC

    International Nuclear Information System (INIS)

    Hunt, E.S.

    1992-01-01

    Remediating primary water stress corrosion cracking (PWSCC) is usually directed towards one of the three causes of PWSCC, material susceptiability, tensile stress, and an aggressive environment. The most practical remedial measures for primary loop penetration of PWSCC are considered to be shot peening, electropolishing, stress relief, and electroplating. The objective of shot peening is to induce a comprehensive residual stress on surfaces of Inconel 600 which are exposed to aggressive environments. Experience with steam generator tubes has shown this method is most effective if applied before PWSCC occurs. If it has already occurred, then the peening may retard but not arrest the corrosion. Electroplating consists of plating the inside surface of the Inconel 600 penetration with pure nickel. One of the major problems with this method was in obtaining surfaces uniformly free from pitting and roughness. Electropolishing for PWSCC remediation would remove the high strength cold work surfaces on the insides of nozzles which are produced by mechanical working e.g. machining. 5 figs

  17. A comparison of small-area estimation techniques to estimate selected stand attributes using LiDAR-derived auxiliary variables

    Science.gov (United States)

    Michael E. Goerndt; Vicente J. Monleon; Hailemariam. Temesgen

    2011-01-01

    One of the challenges often faced in forestry is the estimation of forest attributes for smaller areas of interest within a larger population. Small-area estimation (SAE) is a set of techniques well suited to estimation of forest attributes for small areas in which the existing sample size is small and auxiliary information is available. Selected SAE methods were...

  18. Development of acoustically lined ejector technology for multitube jet noise suppressor nozzles by model and engine tests over a wide range of jet pressure ratios and temperatures

    Science.gov (United States)

    Atvars, J.; Paynter, G. C.; Walker, D. Q.; Wintermeyer, C. F.

    1974-01-01

    An experimental program comprising model nozzle and full-scale engine tests was undertaken to acquire parametric data for acoustically lined ejectors applied to primary jet noise suppression. Ejector lining design technology and acoustical scaling of lined ejector configurations were the major objectives. Ground static tests were run with a J-75 turbojet engine fitted with a 37-tube, area ratio 3.3 suppressor nozzle and two lengths of ejector shroud (L/D = 1 and 2). Seven ejector lining configurations were tested over the engine pressure ratio range of 1.40 to 2.40 with corresponding jet velocities between 305 and 610 M/sec. One-fourth scale model nozzles were tested over a pressure ratio range of 1.40 to 4.0 with jet total temperatures between ambient and 1088 K. Scaling of multielement nozzle ejector configurations was also studied using a single element of the nozzle array with identical ejector lengths and lining materials. Acoustic far field and near field data together with nozzle thrust performance and jet aerodynamic flow profiles are presented.

  19. Two-phase flow in a diverging nozzle

    International Nuclear Information System (INIS)

    Wadle, M.

    1986-05-01

    Stationary two-phase flow experiments were performed with steam-water and air-water mixtures in a well-instrumented horizontal diverging nozzle. The test section consisted of a constant diameter tube, the friction-section, followed by an expansion, the diffusor, which has a tanh-contour and finally another constant diameter tube. The diameter ratio sigma=D1/D2 is 16/80. For the steam-water experiments the flow parameters were: 0 2 and for air-water mixtures (0 2 ). The initial conditions were varied to achieve subcritical and critical mass flow rates. A new model for the pressure recovery in an abrupt expansion is presented. It is based on the superficial velocity concept and agrees well with the steam-water and the water-air experimental data as well as with the experiments of other authors. The experiments were also calculated with the two-phase code DUESE. The Drift-Flux models in this code as well as the constitutive correlations and their empirical constants could be tested. It is shown, that a 1D Drift-Flux code can handle the highly transient flow in the diffusor if the proper drift model is used. In a 1D simulation it is only necessary that the computational flow area is expanded to its full width within an axial length which is equivalent to the real contour. (orig./GL) [de

  20. Nucleation of super-critical carbon dioxide in a venturi nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Jarrahbashi, D., E-mail: dorrin.jarrahbashi@me.gatech.edu; Pidaparti, S.R.; Ranjan, D.

    2016-12-15

    Highlights: • Nucleation of S-CO{sub 2} in a nozzle near critical point has been computationally studied. • The nucleation behavior is very sensitive to the inlet pressure and temperature. • After nucleation, high liquid-content two-phase mixture near wall travels downstream. - Abstract: Pressure reduction at the entrance of the compressor in supercritical CO{sub 2} Brayton cycles may cause nucleation and create a mixture of vapor and liquid droplets due to operation near the saturation conditions. Transient behavior of the flow after nucleation may cause serious issues in operation of the cycle and degrade the materials used in the design. The nucleation behavior of supercritical carbon-dioxide inside a venturi nozzle near the critical point is computationally studied. A transient compressible 3D Navier–Stokes solver, coupled with continuity, and energy equations have been implemented. In order to expedite the simulations, Fluid property Interpolation Tables (FIT) based on a piecewise biquintic spline interpolation of Helmholtz energy have been integrated with OpenFOAM to model S-CO{sub 2} properties. The mass fraction of vapor created in the venturi nozzle has been calculated using homogeneous equilibrium model (HEM). Nucleation behavior has been shown to be very sensitive to the inlet pressure, inlet temperature, and flow rate. The flow conditions that led to nucleation were identified. Nucleation was observed in the throat area and divergent section of the nozzle for mass flow rates from 0.050 kg/s to 0.065 kg/s, inlet pressure from 7.8 to 7.4 MPa for fixed exit pressure equal to 7.28 MPa. The inception of high-vapor-content nucleation was first observed in the throat area away from the side walls that remained confined to the throat region in later times. However, near the walls, a high liquid-content two-phase region was detected, first in the divergent section. At later times, the two-phase region was convected downstream toward the nozzle exit

  1. Variability in core areas of spider monkeys (Ateles geoffroyi) in a tropical dry forest in Costa Rica.

    Science.gov (United States)

    Asensio, Norberto; Schaffner, Colleen M; Aureli, Filippo

    2012-04-01

    Core areas are highly used parts of the home range on which the survival of solitary or group-living animals depends. We investigated the home range and core area size and area fidelity of a spider monkey community in a tropical dry forest over a 4-year period. Home ranges overlapped extensively across years, subgroup sizes, and seasons. In contrast, spider monkeys used core areas that varied in size and location across the study years, subgroup sizes, and seasons. These shifts in core areas suggest that the understanding of core areas, and thus the spatial requirements, of a species in a particular habitat may be limited if based on short-term studies. In this respect, our findings emphasize the importance of long-term studies of the spatial ecology of any species in a particular habitat. Our study also shows that the yearly home range basically includes all the core areas from different years, seasons, and subgroup sizes (i.e., the super-core area). This is conceptually important for territorial species, such as spider monkeys, which defend a stable home range as it contains not only the current, but also the future core areas.

  2. Elliptic nozzle aspect ratio effect on controlled jet propagation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S M Aravindh; Rathakrishnan, Ethirajan, E-mail: aravinds@iitk.ac.in, E-mail: erath@iitk.ac.in [Department of Aerospace Engineering, Indian Institute of Technology, Kanpur (India)

    2017-04-15

    The present study deals with the control of a Mach 2 elliptic jet from a convergent–divergent elliptic nozzle of aspect ratio 4 using tabs at the nozzle exit. The experiments were carried out for rectangular and triangular tabs of the same blockage, placed along the major and minor axes of the nozzle exit, at different levels of nozzle expansion. The triangular tabs along the minor axis promoted superior mixing compared to the other controlled jets and caused substantial core length reduction at all the nozzle pressure ratios studied. The rectangular tabs along the minor axis caused core length reduction at all pressure ratios, but the values were minimal compared to that of triangular tabs along the minor axis. For all the test conditions, the mixing promotion caused by tabs along the major axis was inferior to that of tabs along the minor axis. The waves present in the core of controlled jets were visualized using a shadowgraph. Comparison of the present results with the results of a controlled Mach 2 elliptic jet of aspect ratio 2 (Aravindh Kumar and Sathakrishnan 2016 J. Propulsion Power 32 121–33, Aravindh Kumar and Rathakrishnan 2016 J. Aerospace Eng. at press (doi:10.1177/0954410016652921)) show that for all levels of expansion, the mixing effectiveness of triangular tabs along the minor axis of an aspect ratio 4 nozzle is better than rectangular or triangular tabs along the minor axis of an aspect ratio 2 nozzle. (paper)

  3. Elliptic nozzle aspect ratio effect on controlled jet propagation

    International Nuclear Information System (INIS)

    Kumar, S M Aravindh; Rathakrishnan, Ethirajan

    2017-01-01

    The present study deals with the control of a Mach 2 elliptic jet from a convergent–divergent elliptic nozzle of aspect ratio 4 using tabs at the nozzle exit. The experiments were carried out for rectangular and triangular tabs of the same blockage, placed along the major and minor axes of the nozzle exit, at different levels of nozzle expansion. The triangular tabs along the minor axis promoted superior mixing compared to the other controlled jets and caused substantial core length reduction at all the nozzle pressure ratios studied. The rectangular tabs along the minor axis caused core length reduction at all pressure ratios, but the values were minimal compared to that of triangular tabs along the minor axis. For all the test conditions, the mixing promotion caused by tabs along the major axis was inferior to that of tabs along the minor axis. The waves present in the core of controlled jets were visualized using a shadowgraph. Comparison of the present results with the results of a controlled Mach 2 elliptic jet of aspect ratio 2 (Aravindh Kumar and Sathakrishnan 2016 J. Propulsion Power 32 121–33, Aravindh Kumar and Rathakrishnan 2016 J. Aerospace Eng. at press (doi:10.1177/0954410016652921)) show that for all levels of expansion, the mixing effectiveness of triangular tabs along the minor axis of an aspect ratio 4 nozzle is better than rectangular or triangular tabs along the minor axis of an aspect ratio 2 nozzle. (paper)

  4. Fluid Structure Interaction in a Cold Flow Test and Transient CFD Analysis of Out-of-Round Nozzles

    Science.gov (United States)

    Ruf, Joseph; Brown, Andrew; McDaniels, David; Wang, Ten-See

    2010-01-01

    This viewgraph presentation describes two nozzle fluid flow interactions. They include: 1) Cold flow nozzle tests with fluid-structure interaction at nozzle separated flow; and 2) CFD analysis for nozzle flow and side loads of nozzle extensions with various out-of-round cases.

  5. Variability modes of precipitation along a Central Mediterranean area and their relations with ENSO, NAO, and other climatic patterns

    Science.gov (United States)

    Kalimeris, Anastasios; Ranieri, Ezio; Founda, Dimitra; Norrant, Caroline

    2017-12-01

    This study analyses a century-long set of precipitation time series in the Central Mediterranean (encompassing the Greek Ionian and the Italian Puglia regions) and investigates the statistically significant modes of the interannual precipitation variability using efficient methods of spectral decomposition. The statistical relations and the possible physical couplings between the detected modes and the global or hemispheric patterns of climatic variability (the El Niño Southern Oscillation or ENSO, the North Atlantic Oscillation or NAO, the East Atlantic or EA, the Scandinavian or SCAND, and others) were examined in the time-frequency domain and low-order synchronization events were sought. Significant modes of precipitation variability were detected in the Taranto Gulf and the southern part of the Greek Ionian region at the sub-decadal scales (mostly driven by the SCAND pattern) and particularly at the decadal and quasi-decadal scales, where strong relations found with the ENSO activity (under complex implications of EA and NAO) prior to the 1930s or after the early-1970s. The precipitation variations in the Adriatic stations of Puglia are dominated by significant bi-decadal modes which found to be coherent with the ENSO activity and also weakly related with the Atlantic Ocean sea surface temperature intrinsic variability. Additionally, important discontinuities characterize the evolution of precipitation in certain stations of the Taranto Gulf and the Greek Ionian region during the early-1960s and particularly during the early-1970s, followed by significant reductions in the mean annual precipitation. These discontinuities seem to be associated with regional effects of NAO and SCAND, probably combined with the impact of the 1970s climatic shift in the Pacific and the ENSO variability.

  6. Spatial and Temporal Variability of Carbon Dioxide Using Structure Functions in Urban Areas: Insights for Future Active Remote CO2 Sensors

    Science.gov (United States)

    Choi, Yonghoon; Yang, Melissa; Kooi, Susan A.; Browell, Edward V.; DiGangi, Joshua P.

    2015-01-01

    High resolution in-situ CO2 measurements were recorded onboard the NASA P-3B during the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) Field Campaigns during July 2011 over Washington DC/Baltimore, MD; January-February 2013 over the San Joaquin Valley, CA; September 2013 over Houston, TX; and July-August 2014 over Denver, CO. Each of these campaigns have approximately two hundred vertical soundings of CO2 within the lower troposphere (surface to about 5 kilometers) at 6-8 different sites in each of the urban areas. In this study, we used structure function analysis, which is a useful way to quantify spatial and temporal variability, by displaying differences with average observations, to evaluate the variability of CO2 in the 0-2 kilometers range (representative of the planetary boundary layer). These results can then be used to provide guidance in the development of science requirements for the future ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission to measure near-surface CO2 variability in different urban areas. We also compare the observed in-situ CO2 variability with the variability of the CO2 column-averaged optical depths in the 0-1 kilometer and 0-3.5 kilometers altitude ranges in the four geographically different urban areas, using vertical weighting functions for potential future ASCENDS lidar CO2 sensors operating in the 1.57 and 2.05 millimeter measurement regions. In addition to determining the natural variability of CO2 near the surface and in the column, radiocarbon method using continuous CO2 and CO measurements are used to examine the variation of emission quantification between anthropogenic and biogenic sources in the DC/Maryland urban site.

  7. Critical flashing flows in nozzles with subcooled inlet conditions

    International Nuclear Information System (INIS)

    Abuaf, N.; Jones, O.C. Jr.; Wu, B.J.C.

    1983-01-01

    Examination of a large number of experiments dealing with flashing flows in converging and converging-diverging nozzles reveals that knowledge of the flashing inception point is the key to the prediction of critical flow rates. An extension of the static flashing inception correlation of Jones [16] and Alamgir and Lienhard [17] to flowing systems has allowed the determination of the location of flashing inception in nozzle flows with subcooled inlet conditions. It is shown that in all the experiments examined with subcooled inlet regardless of the degree of inlet subcooling, flashing inception invariably occurred very close to the throat. A correlation is given to predict flashing inception in both pipes and nozzles which matches all data available, but is lacking verification in intermediate nozzle geometries where turbulence may be important. A consequence of this behavior is that the critical mass flux may be correlated to the pressure difference between the nozzle inlet and flashing inception, through a single phase liquid discharge coefficient and an accurate prediction of the flashing inception pressure at the throat. Comparison with the available experiments indicate that the predicted mass fluxes are within 5 percent of the measurements

  8. Thermal-Hydraulic Performance of Scrubbing Nozzle Used for CFVS

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Chul; Lee, Doo Yong; Jung, Woo Young; Lee, Jong Chan; Kim, Gyu Tae [FNC TECH, Yongin (Korea, Republic of)

    2016-05-15

    A Containment Filtered Venting System (CFVS) is the most interested device to mitigate a threat against containment integrity under the severe accident of nuclear power plant by venting with the filtration of the fission products. FNC technology and partners have been developed the self-priming scrubbing nozzle used for the CFVS which is based on the venturi effect. The thermal-hydraulic performances such as passive scrubbing water suction as well as pressure drop across the nozzle have been tested under various thermal-hydraulic conditions. The two types of test section have been built for testing the thermal-hydraulic performance of the self-priming scrubbing nozzle. Through the visualization loop, the liquid suction performance through the slit, pressure drop across the nozzle are measured. The passive water suction flow through the suction slit at the throat is important parameter to define the scrubbing performance of the self-priming scrubbing nozzle. The water suction flow is increased with the increase of the overhead water level at the same inlet gas flow. It is not so much changed with the change of inlet gas flow at the overhead water level.

  9. Extending cavitation models to subcooled and superheated nozzle flow

    International Nuclear Information System (INIS)

    Schmidt, D.P.; Corradini, M.L.

    1997-01-01

    Existing models for cavitating flow are extended to apply to discharge of hot liquid through nozzles. Two types of models are considered: an analytical model and a two-dimensional numerical model. The analytical model of cavitating nozzle flow is reviewed and shown to apply to critical nozzle flow where the liquid is subcooled with respect to the downstream conditions. In this model the liquid and vapor are assumed to be in thermodynamic equilibrium. The success of this analytical model suggests that hydrodynamic effects dominate the subcooled nozzle flow. For more detailed predictions an existing multi-dimensional cavitation model based on hydrodynamic non-equilibrium is modified to apply to discharge of hot liquid. Non-equilibrium rate data from experimental measurements are used to close the equations. The governing equations are solved numerically in time and in two spatial dimensions on a boundary fitted grid. Results are shown for flow through sharp nozzles, and the coefficient of discharge is found to agree with experimental measurements for both subcooled and flashing fluid. (author)

  10. Next-generation nozzle check valve significantly reduces operating costs

    Energy Technology Data Exchange (ETDEWEB)

    Roorda, O. [SMX International, Toronto, ON (Canada)

    2009-01-15

    Check valves perform an important function in preventing reverse flow and protecting plant and mechanical equipment. However, the variety of different types of valves and extreme differences in performance even within one type can change maintenance requirements and life cycle costs, amounting to millions of dollars over the typical 15-year design life of piping components. A next-generation non-slam nozzle check valve which prevents return flow has greatly reduced operating costs by protecting the mechanical equipment in a piping system. This article described the check valve varieties such as the swing check valve, a dual-plate check valve, and nozzle check valves. Advancements in optimized design of a non-slam nozzle check valve were also discussed, with particular reference to computer flow modelling such as computational fluid dynamics; computer stress modelling such as finite element analysis; and flow testing (using rapid prototype development and flow loop testing), both to improve dynamic performance and reduce hydraulic losses. The benefits of maximized dynamic performance and minimized pressure loss from the new designed valve were also outlined. It was concluded that this latest non-slam nozzle check valve design has potential applications in natural gas, liquefied natural gas, and oil pipelines, including subsea applications, as well as refineries, and petrochemical plants among others, and is suitable for horizontal and vertical installation. The result of this next-generation nozzle check valve design is not only superior performance, and effective protection of mechanical equipment but also minimized life cycle costs. 1 fig.

  11. The role of nozzle convergence in diesel combustion

    Energy Technology Data Exchange (ETDEWEB)

    J. Benajes; S. Molina; C. Gonzaalez; R. Donde [CMT-Motores Termicos, Universidad Politecnica de Valencia, Valencia (Spain)

    2008-08-15

    An experimental study has been performed for identifying the role of injector nozzle hole convergence and cavitation in diesel engine combustion and pollutant emissions. For doing so, five nozzles were tested under different operating and experimental conditions. The critical cavitation number of each nozzle was analyzed. With this value, an estimation of the mixing process at different conditions obtained. This data is used to explain the combustion results which are analyzed in terms of the apparent combustion time, rate of heat release, in-cylinder pressures, adiabatic temperatures and soot and NOx emissions. Special emphasis is put in developing an expression to explicitly link the mixing process and the injection rate with the rate of heat release. The results show that the fuel-air mixing process can be improved by the use of both convergent and cavitating nozzles, thus lowering the soot emissions. The NOx production, being dependent of the injection rate and the mixing process, does not necessarily increase with the use of more convergent nozzles. 40 refs., 8 fig., tabs.

  12. Quantifying spatial and temporal variability of methane emissions from a complex area source: case study of a central Indiana landfill

    Science.gov (United States)

    strengths, limitations, and uncertainties of these two approaches. Because US landfills are highly-engineered and composed of daily, intermediate, and final cover areas with differing thicknesses, composition, and implementation of gas recovery, we also expected different emissi...

  13. Dimpled/grooved face on a fuel injection nozzle body for flame stabilization and related method

    Science.gov (United States)

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo; Zuo, Baifang

    2013-08-20

    A fuel injection head for a fuel nozzle used in a gas turbine combustor includes a substantially hollow body formed with an upstream end face, a downstream end face and a peripheral wall extending therebetween. A plurality of pre-mix tubes or passages extend axially through the hollow body with inlets at the upstream end face and outlets at the downstream end face. An exterior surface of the downstream end face is formed with three-dimensional surface features that increase a total surface area of the exterior surface as compared to a substantially flat, planar downstream end face.

  14. Mapping area variability in social and behavioural difficulties among Glasgow pre-schoolers: linkage of a survey of pre-school staff with routine monitoring data.

    Science.gov (United States)

    Barry, S J E; Marryat, L; Thompson, L; Ellaway, A; White, J; McClung, M; Wilson, P

    2015-11-01

    Social, emotional and behavioural development in early to middle childhood impact upon many outcomes in future life and are influenced by home, neighbourhood and school environments. We used linked data to investigate differences between areas in Glasgow City in level of difficulties in pre-school age children, after consideration of demographics, including area-level deprivation. Pre-school education staff completed Strengths and Difficulties Questionnaires (SDQ) on all children progressing to school from a local authority or partnership (local authority-funded private) pre-school in Glasgow City between 2010 and 2012. These data were linked to individual (age, gender) and area-level (deprivation) demographics from the City Council Education Services Department. Statistical models were fitted to the SDQ scores, adjusting for age, gender, area deprivation, year of school entry, pre-school establishment attended and electoral ward of residence. Correlation between neighbouring wards was incorporated to allow for clustering of scores. Boys and those living in more deprived areas had higher levels of difficulties. Children aged 5.0-5.5 years had fewest difficulties, while the oldest and youngest children had similar levels of difficulties. There were no significant secular trends by year of school entry. There remained differences among areas after adjusting for these variables, with children living in some areas having fewer difficulties than would be expected based on their socio-demographic characteristics. There remained differences in children's levels of difficulties between areas after adjusting for age, gender, area deprivation and year of school entry. Children in some very deprived areas had fewer difficulties than might be expected, while those in relatively affluent areas had more difficulties than expected based on their deprivation level. There may be other, unmeasured, individual- and area-level reasons for children's level of difficulties, and these

  15. Plasma acceleration by magnetic nozzles and shock waves

    International Nuclear Information System (INIS)

    Hattori, Kunihiko; Murakami, Fumitake; Miyazaki, Hiroyuki; Imasaki, Atsushi; Yoshinuma, Mikirou; Ando, Akira; Inutake, Masaaki

    2001-01-01

    We have measured axial profiles of ion acoustic Mach number, M i , of a plasma flow blowing off from an MPD (magneto-plasma-dynamic) arc-jet in various magnetic configurations. It is found that the Mach number increases in a divergent nozzle up to 3, while it stays at about unity in a uniform magnetic channel. When a magnetic bump is added in the exit of the divergent magnetic nozzle, the Mach number suddenly decreases below unity, due to an occurrence of shock wave. The subsonic flow after the shock wave is re-accelerated to a supersonic flow through a magnetic Laval nozzle. This behavior is explained well by the one-dimensional isotropic flow model. The shock wave is discussed in relation to the Rankine-Hugoniot relation. (author)

  16. Nuclear reactor fuel assembly with a removably top nozzle

    International Nuclear Information System (INIS)

    Shallenberger, J.M.; Ferlan, S.J.

    1985-01-01

    The invention relates to a nuclear fuel assembly having an improved attaching structure for removably mounting the top nozzle of the fuel assembly on the upper end of a control-rod guide thimble. The attaching structure comprises an outer socket defined in a portion of the top nozzle, an inner socket extending from the upper end of the guide thimble and removably received in the outer socket for interlocking engagement therewith, and an elongate locking member adapted to be inserted into the inner socket to maintain said interlocking engagement. Removal of the locking member from the inner socket enables the latter to be withdrawn from the outer socket, thereby enabling the top nozzle to be removed from the guide thimble

  17. Top-nozzle mounted replacement guide pin assemblies

    International Nuclear Information System (INIS)

    Gilmore, C.B.; Andrews, W.H.

    1993-01-01

    A replacement guide pin assembly is provided for aligning a nuclear fuel assembly with an upper core plate of a nuclear reactor core. The guide pin assembly includes a guide pin body having a radially expandable base insertable within a hole in the top nozzle, a ferrule insertable within the guide pin base and capable of imparting a radially and outwardly directed force on the expandable base to expand it within the hole of the top nozzle and thereby secure the guide pin body to the top nozzle in response to a predetermined displacement of the ferrule relative to the guide pin body along its longitudinal axis, and a lock screw interfitted with the ferrule and threaded into the guide pin body so as to produce the predetermined displacement of the ferrule. (author)

  18. Effect of nozzle geometry for swirl type twin-fluid water mist nozzle on the spray characteristic

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Soon Hyun; Kim, Do Yeon; Kim, Dong Keon [Pusan National University, Busan (Korea, Republic of); Kim, Bong Hwan [Jinju National University, Jinju (Korea, Republic of)

    2011-07-15

    Experimental investigations on the atomization characteristics of twin-fluid water mist nozzle were conducted using particle image velocimetry (PIV) system and particle motion analysis system (PMAS). The twin-fluid water mist nozzles with swirlers designed two types of swirl angles such as 0 .deg. , 90 .deg. and three different size nozzle hole diameters such as 0.5mm, 1mm, 1.5mm were employed. The experiments were carried out by the injection pressure of water and air divided into 1bar, 2bar respectively. The droplet size of the spray was measured using PMAS. The velocity and turbulence intensity were measured using PIV. The velocity, turbulence intensity and SMD distributions of the sprays were measured along the centerline and radial direction. As the experimental results, swirl angle controlled to droplet sizes. It was found that SMD distribution decreases with the increase of swirl angle. The developed twin-fluid water mist nozzle was satisfied to the criteria of NFPA 750, Class 1. It was proven that the developed nozzle under low pressures could be applied to fire protection system.

  19. Effect of nozzle geometry for swirl type twin-fluid water mist nozzle on the spray characteristic

    International Nuclear Information System (INIS)

    Yoon, Soon Hyun; Kim, Do Yeon; Kim, Dong Keon; Kim, Bong Hwan

    2011-01-01

    Experimental investigations on the atomization characteristics of twin-fluid water mist nozzle were conducted using particle image velocimetry (PIV) system and particle motion analysis system (PMAS). The twin-fluid water mist nozzles with swirlers designed two types of swirl angles such as 0 .deg. , 90 .deg. and three different size nozzle hole diameters such as 0.5mm, 1mm, 1.5mm were employed. The experiments were carried out by the injection pressure of water and air divided into 1bar, 2bar respectively. The droplet size of the spray was measured using PMAS. The velocity and turbulence intensity were measured using PIV. The velocity, turbulence intensity and SMD distributions of the sprays were measured along the centerline and radial direction. As the experimental results, swirl angle controlled to droplet sizes. It was found that SMD distribution decreases with the increase of swirl angle. The developed twin-fluid water mist nozzle was satisfied to the criteria of NFPA 750, Class 1. It was proven that the developed nozzle under low pressures could be applied to fire protection system

  20. The modelling of an SF6 arc in a supersonic nozzle: II. Current zero behaviour of the nozzle arc

    International Nuclear Information System (INIS)

    Zhang, Q; Liu, J; Yan, J D; Fang, M T C

    2016-01-01

    The present work (part II) forms the second part of an investigation into the behaviour of SF 6 nozzle arc. It is concerned with the aerodynamic and electrical behaviour of a transient nozzle arc under a current ramp specified by a rate of current decay (d i /d t ) before current zero and a voltage ramp (d V /d t ) after current zero. The five flow models used in part I [1] for cold gas flow and DC nozzle arcs have been applied to study the transient arc at three stagnation pressures ( P 0 ) and two values of d i /d t for the current ramp, representing a wide range of arcing conditions. An analysis of the physical mechanisms encompassed in each flow model is given with an emphasis on the adequacy of a particular model in describing the rapidly varying arc around current zero. The critical rate of rise of recovery voltage (RRRV) is found computationally and compared with test results of Benenson et al [2]. For transient nozzle arcs, the RRRV is proportional to the square of P 0 , rather than to the square root of P 0 for DC nozzle arcs. The physical mechanisms responsible for the strong dependence of RRRV on P 0 have been investigated. The relative merits of the flow models employed are discussed. (paper)

  1. Diel activity and variability in habitat use of white sea bream in a temperate marine protected area.

    Science.gov (United States)

    Di Lorenzo, Manfredi; Fernández, Tomás Vega; Badalamenti, Fabio; Guidetti, Paolo; Starr, Richard M; Giacalone, Vincenzo Maximiliano; Di Franco, Antonio; D'Anna, Giovanni

    2016-05-01

    Fish populations are often comprised of individuals that use habitats and associated resources in different ways. We placed sonic transmitters in, and tracked movements of, white sea bream (Diplodus sargus sargus) in the no-take zone of a Mediterranean marine protected area: the Torre Guaceto marine protected area, (Adriatic Sea, Italy). Tagged fish displayed three types of diel activity patterns in three different habitats: sand, rocky reefs and "matte" of the seagrass Posidonia oceanica. Individuals were more active during the day than at night. Overall, white sea bream displayed a remarkable behavioural plasticity in habitat use. Our results indicate that the observed behavioural plasticity in the marine protected area could be the result of multiple ecological and environmental drivers such as size, sex and increased intra-specific competition. Our findings support the view that habitat diversity helps support high densities of fishes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. RSRM Nozzle-to-Case Joint J-leg Development

    Science.gov (United States)

    Albrechtsen, Kevin U.; Eddy, Norman F.; Ewing, Mark E.; McGuire, John R.

    2003-01-01

    Since the beginning of the Space Shuttle Reusable Solid Rocket Motor (RSRM) program, nozzle-to-case joint polysulfide adhesive gas paths have occurred on several flight motors. These gas paths have allowed hot motor gases to reach the wiper O-ring. Even though these motors continue to fly safely with this condition, a desire was to reduce such occurrences. The RSRM currently uses a J-leg joint configuration on case field joints and igniter inner and outer joints. The J-leg joint configuration has been successfully demonstrated on numerous RSRM flight and static test motors, eliminating hot gas intrusion to the critical O-ring seals on these joints. Using the proven technology demonstrated on the case field joints and igniter joints, a nozzle-to-case joint J-leg design was developed for implementation on RSRM flight motors. This configuration provides an interference fit with nozzle fixed housing phenolics at assembly, with a series of pressurization gaps incorporated outboard of the joint mating surface to aid in joint pressurization and to eliminate any circumferential flow in this region. The joint insulation is bonded to the nozzle phenolics using the same pressure sensitive adhesive used in the case field joints and igniter joints. An enhancement to the nozzle-to-case joint J-leg configuration is the implementation of a carbon rope thermal barrier. The thermal barrier is located downstream of the joint bondline and is positioned within the joint in a manner where any hot gas intrusion into the joint passes through the thermal barrier, reducing gas temperatures to a level that would not affect O-rings downstream of the thermal barrier. This paper discusses the processes used in reaching a final nozzle-to-case joint J-leg design, provides structural and thermal results in support of the design, and identifies fabrication techniques and demonstrations used in arriving at the final configuration.

  3. Optimization design of energy deposition on single expansion ramp nozzle

    Science.gov (United States)

    Ju, Shengjun; Yan, Chao; Wang, Xiaoyong; Qin, Yupei; Ye, Zhifei

    2017-11-01

    Optimization design has been widely used in the aerodynamic design process of scramjets. The single expansion ramp nozzle is an important component for scramjets to produces most of thrust force. A new concept of increasing the aerodynamics of the scramjet nozzle with energy deposition is presented. The essence of the method is to create a heated region in the inner flow field of the scramjet nozzle. In the current study, the two-dimensional coupled implicit compressible Reynolds Averaged Navier-Stokes and Menter's shear stress transport turbulence model have been applied to numerically simulate the flow fields of the single expansion ramp nozzle with and without energy deposition. The numerical results show that the proposal of energy deposition can be an effective method to increase force characteristics of the scramjet nozzle, the thrust coefficient CT increase by 6.94% and lift coefficient CN decrease by 26.89%. Further, the non-dominated sorting genetic algorithm coupled with the Radial Basis Function neural network surrogate model has been employed to determine optimum location and density of the energy deposition. The thrust coefficient CT and lift coefficient CN are selected as objective functions, and the sampling points are obtained numerically by using a Latin hypercube design method. The optimized thrust coefficient CT further increase by 1.94%, meanwhile, the optimized lift coefficient CN further decrease by 15.02% respectively. At the same time, the optimized performances are in good and reasonable agreement with the numerical predictions. The findings suggest that scramjet nozzle design and performance can benefit from the application of energy deposition.

  4. Mapping Fish Community Variables by Integrating Field and Satellite Data, Object-Based Image Analysis and Modeling in a Traditional Fijian Fisheries Management Area

    Directory of Open Access Journals (Sweden)

    Stacy Jupiter

    2011-03-01

    Full Text Available The use of marine spatial planning for zoning multi-use areas is growing in both developed and developing countries. Comprehensive maps of marine resources, including those important for local fisheries management and biodiversity conservation, provide a crucial foundation of information for the planning process. Using a combination of field and high spatial resolution satellite data, we use an empirical procedure to create a bathymetric map (RMSE 1.76 m and object-based image analysis to produce accurate maps of geomorphic and benthic coral reef classes (Kappa values of 0.80 and 0.63; 9 and 33 classes, respectively covering a large (>260 km2 traditional fisheries management area in Fiji. From these maps, we derive per-pixel information on habitat richness, structural complexity, coral cover and the distance from land, and use these variables as input in models to predict fish species richness, diversity and biomass. We show that random forest models outperform five other model types, and that all three fish community variables can be satisfactorily predicted from the high spatial resolution satellite data. We also show geomorphic zone to be the most important predictor on average, with secondary contributions from a range of other variables including benthic class, depth, distance from land, and live coral cover mapped at coarse spatial scales, suggesting that data with lower spatial resolution and lower cost may be sufficient for spatial predictions of the three fish community variables.

  5. Effects of canopy structural variables on retrieval of leaf dry matter content and specific leaf area from remotely sensed data

    NARCIS (Netherlands)

    Ali, A.M.; Darvishzadeh, R.; Skidmore, A.K.; van Duren, I.C.

    2016-01-01

    Leaf dry matter content (LDMC) and specific leaf area (SLA) are two important traits in measuring biodiversity. To use remote sensing for the estimation of these traits, it is essential to understand the underlying factors that influence their relationships with canopy reflectance. The effect of

  6. Simulating Lake-Groundwater Interactions During Decadal Climate Cycles: Accounting For Variable Lake Area In The Watershed

    Science.gov (United States)

    Virdi, M. L.; Lee, T. M.

    2009-12-01

    The volume and extent of a lake within the topo-bathymetry of a watershed can change substantially during wetter and drier climate cycles, altering the interaction of the lake with the groundwater flow system. Lake Starr and other seepage lakes in the permeable sandhills of central Florida are vulnerable to climate changes as they rely exclusively on rainfall and groundwater for inflows in a setting where annual rainfall and recharge vary widely. The groundwater inflow typically arrives from a small catchment area bordering the lake. The sinkhole origin of these lakes combined with groundwater pumping from underlying aquifers further complicate groundwater interactions. Understanding the lake-groundwater interactions and their effects on lake stage over multi-decadal climate cycles is needed to manage groundwater pumping and public expectation about future lake levels. The interdependence between climate, recharge, changing lake area and the groundwater catchment pose unique challenges to simulating lake-groundwater interactions. During the 10-year study period, Lake Starr stage fluctuated more than 13 feet and the lake surface area receded and expanded from 96 acres to 148 acres over drier and wetter years that included hurricanes, two El Nino events and a La Nina event. The recently developed Unsaturated Zone Flow (UZF1) and Lake (LAK7) packages for MODFLOW-2005 were used to simulate the changing lake sizes and the extent of the groundwater catchment contributing flow to the lake. The lake area was discretized to occupy the largest surface area at the highest observed stage and then allowed to change size. Lake cells convert to land cells and receive infiltration as receding lake area exposes the underlying unsaturated zone to rainfall and recharge. The unique model conceptualization also made it possible to capture the dynamic size of the groundwater catchment contributing to lake inflows, as the surface area and volume of the lake changed during the study

  7. AND - Advanced Nozzle Design; Entwurf eines fortgeschrittenen Stutzendesigns

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, A.; Wernicke, R. [TUEV NORD SysTec, Hamburg (Germany). Mechanische Analyse; Friedrich, M. [FE-DESIGN GmbH, Karlsruhe (Germany). Engineering Services

    2006-07-01

    In this paper it is shown by the example of a nozzle optimisation that the improvement of the traditional component design like nozzles and high pressure header may lead to an increase of the long-time creep resistance. In a next step - on the basis of these results - software tools could be developed, which enable the designing engineer to accomplish a design without complex and costly FEM computations. In the context of a prototype building the manufacturing conditions are to be specified. (orig.)

  8. Shelf life extension for the lot AAE nozzle severance LSCs

    Science.gov (United States)

    Cook, M.

    1990-01-01

    Shelf life extension tests for the remaining lot AAE linear shaped charges for redesigned solid rocket motor nozzle aft exit cone severance were completed in the small motor conditioning and firing bay, T-11. Five linear shaped charge test articles were thermally conditioned and detonated, demonstrating proper end-to-end charge propagation. Penetration depth requirements were exceeded. Results indicate that there was no degradation in performance due to aging or the linear shaped charge curving process. It is recommended that the shelf life of the lot AAE nozzle severance linear shaped charges be extended through January 1992.

  9. Measurement of unsteady airflow velocity at nozzle outlet

    Science.gov (United States)

    Pyszko, René; Machů, Mário

    2017-09-01

    The paper deals with a method of measuring and evaluating the cooling air flow velocity at the outlet of the flat nozzle for cooling a rolled steel product. The selected properties of the Prandtl and Pitot sensing tubes were measured and compared. A Pitot tube was used for operational measurements of unsteady dynamic pressure of the air flowing from nozzles to abtain the flow velocity. The article also discusses the effects of air temperature, pressure and relative air humidity on air density, as well as the influence of dynamic pressure filtering on the error of averaged velocity.

  10. Numerical study on drop formation through a micro nozzle

    International Nuclear Information System (INIS)

    Kim, Sung Il; Son, Gi Hun

    2005-01-01

    The drop ejection process from a micro nozzle is investigated by numerically solving the conservation equations for mass and momentum. The liquid-gas interface is tracked by a level set method which is extended for two-fluid flows with irregular solid boundaries. Based on the numerical results, the liquid jet breaking and droplet formation behavior is found to depend strongly on the pulse type of forcing pressure and the contact angle at the gas-liquid-solid interline. The negative pressure forcing can be used to control the formation of satelite droplets. Also, various nozzle shapes are tested to investigate their effect on droplet formation

  11. Multiple-Nozzle Spray Head Applies Foam Insulation

    Science.gov (United States)

    Walls, Joe T.

    1993-01-01

    Spray head equipped with four-nozzle turret mixes two reactive components of polyurethane and polyisocyanurate foam insulating material and sprays reacting mixture onto surface to be insulated. If nozzle in use becomes clogged, fresh one automatically rotated into position, with minimal interruption of spraying process. Incorporates features recirculating and controlling pressures of reactive components to maintain quality of foam by ensuring proper blend at outset. Also used to spray protective coats on or in ships, aircraft, and pipelines. Sprays such reactive adhesives as epoxy/polyurethane mixtures. Components of spray contain solid-particle fillers for strength, fire retardance, toughness, resistance to abrasion, or radar absorption.

  12. PHENOTYPIC VARIABILITY IN FEIJOA FRUITS [Acca sellowiana (O. Berg. Burret] ON INDIGENOUS LANDS,QUILOMBOLAS COMMUNITIES AND PROTECTED AREAS IN THE SOUTH OF BRAZIL

    Directory of Open Access Journals (Sweden)

    LIDO JOSÉ BORSUK

    Full Text Available ABSTRACT Phenotypic studies with native fruits are important sources of information for understanding the status of conservation of plant species, especially populations in protected areas (PAs. Fruits of 18 populations of feijoa [Acca sellowiana (O. Berg. Burret] present in three kind of PAs, Quilombolas Communities (QLs, Indigenous Lands (ILs and Conservation Units (CUs were evaluated with the aim to characterize the phenotypic variability. Fruits were harvested at maturity and eight morphological descriptors were measured: diameter, length, total weight, pericarp weight, pulp weight, pericarp thickness, pulp yield and solid soluble contents (°Brix. The results revealed the existence of large morphological variability for all traits, with significant differences among all populations and among those populations grouped in QLs, TIs and UCs, particularly to the total weight and peel thickness. There was a clear formation of five major clusters of genetic dissimilarity. In addition, two Uruguayan type populations and 16 Brazilian type populations showed contrast means for most of the evaluated traits. The lower variability on fruit characters found in plants collected in areas of traditional people but not in CUs suggests the existence of selection processes of feijoa genotypes on those areas.

  13. Advanced supersonic propulsion study, phases 3 and 4. [variable cycle engines

    Science.gov (United States)

    Allan, R. D.; Joy, W.

    1977-01-01

    An evaluation of various advanced propulsion concepts for supersonic cruise aircraft resulted in the identification of the double-bypass variable cycle engine as the most promising concept. This engine design utilizes special variable geometry components and an annular exhaust nozzle to provide high take-off thrust and low jet noise. The engine also provides good performance at both supersonic cruise and subsonic cruise. Emission characteristics are excellent. The advanced technology double-bypass variable cycle engine offers an improvement in aircraft range performance relative to earlier supersonic jet engine designs and yet at a lower level of engine noise. Research and technology programs required in certain design areas for this engine concept to realize its potential benefits include refined parametric analysis of selected variable cycle engines, screening of additional unconventional concepts, and engine preliminary design studies. Required critical technology programs are summarized.

  14. Variable volume combustor with an air bypass system

    Science.gov (United States)

    Johnson, Thomas Edward; Ziminsky, Willy Steve; Ostebee, Heath Michael; Keener, Christopher Paul

    2017-02-07

    The present application provides a combustor for use with flow of fuel and a flow of air in a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles positioned within a liner and an air bypass system position about the liner. The air bypass system variably allows a bypass portion of the flow of air to bypass the micro-mixer fuel nozzles.

  15. Oak Ridge National Laboratory Old Hydrofracture Facility Waste Remediation Using the Borehole-Miner Extendible-Nozzle Sluicer

    Energy Technology Data Exchange (ETDEWEB)

    Bamberger, J.A.; Boris, G.F.

    1999-10-07

    A borehole-miner extendible-nozzle sluicing system was designed, constructed, and deployed at Oak Ridge National Laboratory to remediate five horizontal underground storage tanks containing sludge and supernate at the ORNL Old Hydrofracture Facility site. The tanks were remediated in fiscal year 1998 to remove {approx}98% of the waste, {approx}3% greater than the target removal of >95% of the waste. The tanks contained up to 18 in. of sludge covered by supernate. The 42,000 gal of low level liquid waste were estimated to contain 30,000 Ci, with 97% of this total located in the sludge. The retrieval was successful. At the completion of the remediation, the State of Tennessee Department of Environment and Conservation agreed that the tanks were cleaned to the maximum extent practicable using pumping technology. This deployment was the first radioactive demonstration of the borehole-miner extendible-nozzle water-jetting system. The extendible nozzle is based on existing bore hole-miner technology used to fracture and dislodge ore deposits in mines. Typically borehole-miner technology includes both dislodging and retrieval capabilities. Both dislodging, using the extendible-nozzle water-jetting system, and retrieval, using a jet pump located at the base of the mast, are deployed as an integrated system through one borehole or riser. Note that the extendible-nozzle system for Oak Ridge remediation only incorporated the dislodging capability; the retrieval pump was deployed through a separate riser. The borehole-miner development and deployment is part of the Retrieval Process Development and Enhancements project under the direction of the US Department of Energy's EM-50 Tanks Focus Area. This development and deployment was conducted as a partnership between RPD and E and the Oak Ridge National Laboratory's US DOE EM040 Old Hydrofracture Facility remediation project team.

  16. Oak Ridge National Laboratory Old Hydrofracture Facility Waste Remediation Using the Borehole-Miner Extendible-Nozzle Sluicer

    International Nuclear Information System (INIS)

    Boris, G.F.; Bamberger, J.A.

    1999-01-01

    A borehole-miner extendible-nozzle sluicing system was designed, constructed, and deployed at Oak Ridge National Laboratory to remediate five horizontal underground storage tanks containing sludge and supernate at the ORNL Old Hydrofracture Facility site. The tanks were remediated in fiscal year 1998 to remove approximately98% of the waste, approximately3% greater than the target removal of >95% of the waste. The tanks contained up to 18 in. of sludge covered by supernate. The 42,000 gal of low level liquid waste were estimated to contain 30,000 Ci, with 97% of this total located in the sludge. The retrieval was successful. At the completion of the remediation, the State of Tennessee Department of Environment and Conservation agreed that the tanks were cleaned to the maximum extent practicable using pumping technology. This deployment was the first radioactive demonstration of the borehole-miner extendible-nozzle water-jetting system. The extendible nozzle is based on existing borehole-miner technology used to fracture and dislodge ore deposits in mines. Typically borehole-miner technology includes both dislodging and retrieval capabilities. Both dislodging, using the extendible-nozzle water-jetting system, and retrieval, using a jet pump located at the base of the mast, are deployed as an integrated system through one borehole or riser. Note that the extendible-nozzle system for Oak Ridge remediation only incorporated the dislodging capability; the retrieval pump was deployed through a separate riser. The borehole-miner development and deployment is part of the Retrieval Process Development and Enhancements project under the direction of the US Department of Energy's EM-50 Tanks Focus Area. This development and deployment was conducted as a partnership between RPD and E and the Oak Ridge National Laboratory's US DOE EM040 Old Hydrofracture Facility remediation project team

  17. Control of Surge in Centrifugal Compressor by Using a Nozzle Injection System: Universality in Optimal Position of Injection Nozzle

    Directory of Open Access Journals (Sweden)

    Toshiyuki Hirano

    2012-01-01

    Full Text Available The passive control method for surge and rotating stall in centrifugal compressors by using a nozzle injection system was proposed to extend the stable operating range to the low flow rate. A part of the flow at the scroll outlet of a compressor was recirculated to an injection nozzle installed on the inner wall of the suction pipe of the compressor through the bypass pipe and injected to the impeller inlet. Two types of compressors were tested at the rotational speeds of 50,000 rpm and 60,000 rpm with the parameter of the circumferential position of the injection nozzle. The present experimental results revealed that the optimum circumferential position, which most effectively reduced the flow rate for the surge inception, existed at the opposite side of the tongue of the scroll against the rotational axis and did not depend on the compressor system and the rotational speeds.

  18. Structure Optimization and Numerical Simulation of Nozzle for High Pressure Water Jetting

    Directory of Open Access Journals (Sweden)

    Shuce Zhang

    2015-01-01

    Full Text Available Three kinds of nozzles normally used in industrial production are numerically simulated, and the structure of nozzle with the best jetting performance out of the three nozzles is optimized. The R90 nozzle displays the most optimal jetting properties, including the smooth transition of the nozzle’s inner surface. Simulation results of all sample nozzles in this study show that the helix nozzle ultimately displays the best jetting performance. Jetting velocity magnitude along Y and Z coordinates is not symmetrical for the helix nozzle. Compared to simply changing the jetting angle, revolving the jet issued from the helix nozzle creates a grinding wheel on the cleaning surface, which makes not only an impact effect but also a shearing action on the cleaning object. This particular shearing action improves the cleaning process overall and forms a wider, effective cleaning range, thus obtaining a broader jet width.

  19. Gas flows in radial micro-nozzles with pseudo-shocks

    Science.gov (United States)

    Kiselev, S. P.; Kiselev, V. P.; Zaikovskii, V. N.

    2017-12-01

    In the present paper, results of an experimental and numerical study of supersonic gas flows in radial micro-nozzles are reported. A distinguishing feature of such flows is the fact that two factors, the nozzle divergence and the wall friction force, exert a substantial influence on the flow structure. Under the action of the wall friction force, in the micro-nozzle there forms a pseudo-shock that separates the supersonic from subsonic flow region. The position of the pseudo-shock can be evaluated from the condition of flow blockage in the nozzle exit section. A detailed qualitative and quantitative analysis of gas flows in radial micro-nozzles is given. It is shown that the gas flow in a micro-nozzle is defined by the complicated structure of the boundary layer in the micro-nozzle, this structure being dependent on the width-to-radius ratio of the nozzle and its inlet-to-outlet pressure ratio.

  20. Experimental assessment of heat and mass transfer of modular nozzles of cooling towers

    Science.gov (United States)

    Merentsov, N. A.; Lebedev, V. N.; Golovanchikov, A. B.; Balashov, V. A.; Nefed'eva, E. E.

    2018-01-01

    Data of experimental study of hydrodynamics, heat and mass transfer of modular nozzles of cooling towers and some comparative characteristics of the packed device with nozzles, which have wide industrial application, are given in the article.

  1. Computational Simulation on a Coaxial Substream Powder Feeding Laval Nozzle of Cold Spraying

    Directory of Open Access Journals (Sweden)

    Guosheng HUANG

    2014-09-01

    Full Text Available In this paper, a substream coaxial powder feeding nozzle was investigated for use in cold spraying. The relationship between nozzle structure and gas flow, the acceleration behavior of copper particles were examined by computational simulation method. Also, one of the nozzle was used to spray copper coating on steel substrate. The simulation results indicate that: the velocity of gas at the center of the nozzle is lower than that of the conventional nozzle. Powders are well restrained near the central line of the nozzle, no collision occurred between the nozzle wall and the powders. This type of nozzle with expansion 3.25 can successfully deposit copper coating on steel substrate, the copper coating has low porosity about 3.1 % – 3.8 % and high bonding strength about 23.5 MPa – 26.8 MPa. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4244

  2. Droplet size and velocity at the exit of a nozzle with two-component near critical and critical flow

    International Nuclear Information System (INIS)

    Lemonnier, H.; Camelo-Cavalcanti, E.S.

    1993-01-01

    Two-component critical flow modelling is an important issue for safety studies of various hazardous industrial activities. When the flow quality is high, the critical flow rate prediction is sensitive to the modelling of gas droplet mixture interfacial area. In order to improve the description of these flows, experiments were conducted with air-water flows in converging nozzles. The pressure was 2 and 4 bar and the gas mass quality ranged between 100% and 20%. The droplets size and velocity have been measured close to the outlet section of a nozzle with a 10 mm diameter throat. Subcritical and critical conditions were observed. These data are compared with the predictions of a critical flow model which includes an interfacial area model based on the classical ideas of Hinze and Kolmogorov. (authors). 9 figs., 12 refs

  3. Temporal dynamics and spatial variability in the enhancement of canopy leaf area under elevated atmospheric CO2

    Science.gov (United States)

    Heather R. McCarthy; Ram Oren; Adrien C. Finzi; David S. Ellsworth; Hyun-Seok Kim; Kurt H. Johnsen; Bonnie Millar

    2007-01-01

    Increased canopy leaf area (L) may lead to higher forest productivity and alter processes such as species dynamics and ecosystem mass and energy fluxes. Few CO2enrichment studies have been conducted in closed canopy forests and none have shown a sustained enhancement of L. We reconstructed 8 years (1996–2003) of L at Duke’s Free Air CO...

  4. Recovery trajectories of kelp forest animals are rapid yet spatially variable across a network of temperate marine protected areas

    OpenAIRE

    Caselle, JE; Rassweiler, A; Hamilton, SL; Warner, RR

    2015-01-01

    © 2015, Nature Publishing Group. All rights reserved. Oceans currently face a variety of threats, requiring ecosystem-based approaches to management such as networks of marine protected areas (MPAs). We evaluated changes in fish biomass on temperate rocky reefs over the decade following implementation of a network of MPAs in the northern Channel Islands, California. We found that the biomass of targeted (i.e. fished) species has increased consistently inside all MPAs in the network, with an e...

  5. Environmental variables associated with anopheline larvae distribution and abundance in Yanomami villages within unaltered areas of the Brazilian Amazon.

    Science.gov (United States)

    Sánchez-Ribas, Jordi; Oliveira-Ferreira, Joseli; Gimnig, John E; Pereira-Ribeiro, Cleomar; Santos-Neves, Maycon Sebastião Alberto; Silva-do-Nascimento, Teresa Fernandes

    2017-11-16

    Many indigenous villages in the Amazon basin still suffer from a high malaria burden. Despite this health situation, there are few studies on the bionomics of anopheline larvae in such areas. This publication aims to identify the main larval habitats of the most abundant anopheline species and to assess their associations with some environmental factors. We conducted a 19-month longitudinal study from January 2013 to July 2014, sampling anopheline larvae in two indigenous Yanomami communities, comprised of four villages each. All natural larval habitats were surveyed every two months with a 350 ml manual dipper, following a standardized larval sampling methodology. In a third study area, we conducted two field expeditions in 2013 followed by four systematic collections during the long dry season of 2014-2015. We identified 177 larval habitats in the three study areas, from which 9122 larvae belonging to 13 species were collected. Although species abundance differed between villages, An. oswaldoi (s.l.) was overall the most abundant species. Anopheles darlingi, An. oswaldoi (s.l.), An. triannulatus (s.s.) and An. mattogrossensis were primarily found in larval habitats that were partially or mostly sun-exposed. In contrast, An. costai-like and An. guarao-like mosquitoes were found in more shaded aquatic habitats. Anopheles darlingi was significantly associated with proximity to human habitations and larval habitats associated with river flood pulses and clear water. This study of anopheline larvae in the Brazilian Yanomami area detected high heterogeneities at micro-scale levels regarding species occurrence and densities. Sun exposure was a major modulator of anopheline occurrence, particularly for An. darlingi. Lakes associated with the rivers, and particularly oxbow lakes, were the main larval habitats for An. darlingi and other secondary malaria vectors. The results of this study will serve as a basis to plan larval source management activities in remote

  6. Optimization of operating variables for production of ultra-fine talc in a stirred mill. Specific surface area investigations

    Directory of Open Access Journals (Sweden)

    Toraman Oner Yusuf

    2016-01-01

    Full Text Available Due to its properties such as chemical inertness, softness, whiteness, high thermal conductivity, low electrical conductivity and adsorption properties talc has wide industrial applications in paper, cosmetics, paints, polymer, ceramics, refractory materials and pharmaceutical. The demand for ultra-fine talc is emerging which drives the mineral industry to produce value added products. In this study, it was investigated how certain grinding parameters such as mill speed, ball filling ratio, powder filling ratio and grinding time of dry stirred mill affect grindability of talc ore (d97=127 μm. A series of laboratory experiments using a 24 full factorial design was conducted to determine the optimal operational parameters of a stirred mill in order to minimize the specific surface area. The main and interaction effects on the volume specific surface area (SV, m2.cm−3 of the ground product were evaluated using the Yates analysis. Under the optimal conditions at the stirrer speed of 600 rpm, grinding time of 20 min, sample mass of 5% and ball ratio of 70%, the resulting talc powder had larger volume specific surface area (i.e., 3.48 m2.cm−3 than the starting material (i.e., 1.84 m2.cm−3.

  7. Spatial‑temporal variability of water balance components in the North area of the Zailiisky Alatau Range

    Directory of Open Access Journals (Sweden)

    V. G. Konovalov

    2016-01-01

    Full Text Available Analysis of changes in WB components (precipitation, evaporation, glacier runoff, dynamical water resources on the Northern slope of the Zailiisky Alatau was performed for the 1946–2005 time divided into two periods: 1946–1975 and 1976–2005. The territory under investigation included basins of the following rivers: Bolshaya Almatinka, Malaya Almatinka, Talgar, Turgen, Issyk, Chemolgan, Kaskelen, Kargalinka, Prohodnaya, and Uzunkargaly. Their total area down to the closing gauge points amounts to 2644 km2. Summarized glacier areas in these basins and annual runoff were equal, respectively, to: 306.6 km2 and 39.05 km3in 1946–1975, and 253.0 km2 and 38.35 km3 in 1975–2005. In 1946–2005, typical features of regional glaciation dynamics were increasing area of the moraine cover on glaciers and reducing area of bare ice that results in decreasing of the glacial runoff volume, all other factors being the same. The method to calculate the WB components consists of the following constituents: model of seasonal runoff from melted snow and ice in the areas of accumulation and ablation of glaciers; complex of formulas to calculate precipitation, air temperature and humidity, intensity of ice melting under the moraine, bare ice and evaporation within the height intervals corresponding to the main types of surfaces on the glaciers. On the basis of our method, we could reconstruct for the 1876–2015 period long‑term series of data on a runoff, separately annual values and sums for the vegetation periods. They can be used for regional scientific and applied analyses of the river stream discharges. The data on runoff in the Malaya Almatinka River basin and observational data on the meteorological station Almaty (Hydrometeorological Observatory had been quantitatively substantiated as the representative information for modeling and calculation of water resources on the Northern slope of the Zailiisky Alatau Range.

  8. High Velocity Jet Noise Source Location and Reduction. Task 6. Noise Abatement Nozzle Design Guide.

    Science.gov (United States)

    1979-04-01

    the Conical Nozzle 255 on the Bertin Aerotrain . xvi ji4 ’ . _______ p .. LIST OF ILLUSTRATIONS (Continued) Figure Page D-37. Predicted and Measured...Moving-Frame Noise from the 256 Conical Nozzle on the Bertin Aerotrain . D-38. Predicted and Measured Static Noise from the 104-Tube 257 Nozzle on the...Bertin Aerotrain . D-39. Predicted and Measured Moving-Frame Noise from the 104- 258 Tube Nozzle on the Bertin Aerotrain . D-40. Relative Velocity Index m

  9. Analysis and design of optimized truncated scarfed nozzles subject to external flow effects

    Science.gov (United States)

    Shyne, Rickey J.; Keith, Theo G., Jr.

    1990-01-01

    Rao's method for computing optimum thrust nozzles is modified to study the effects of external flow on the performance of a class of exhaust nozzles. Members of this class are termed scarfed nozzles. These are two-dimensional, nonsymmetric nozzles with a flat lower wall. The lower wall (the cowl) is truncated in order to save weight. Results from a parametric investigation are presented to show the effects of the external flowfield on performance.

  10. Environmental variables associated with anopheline larvae distribution and abundance in Yanomami villages within unaltered areas of the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Jordi Sánchez-Ribas

    2017-11-01

    Full Text Available Abstract Background Many indigenous villages in the Amazon basin still suffer from a high malaria burden. Despite this health situation, there are few studies on the bionomics of anopheline larvae in such areas. This publication aims to identify the main larval habitats of the most abundant anopheline species and to assess their associations with some environmental factors. Methods We conducted a 19-month longitudinal study from January 2013 to July 2014, sampling anopheline larvae in two indigenous Yanomami communities, comprised of four villages each. All natural larval habitats were surveyed every two months with a 350 ml manual dipper, following a standardized larval sampling methodology. In a third study area, we conducted two field expeditions in 2013 followed by four systematic collections during the long dry season of 2014–2015. Results We identified 177 larval habitats in the three study areas, from which 9122 larvae belonging to 13 species were collected. Although species abundance differed between villages, An. oswaldoi (s.l. was overall the most abundant species. Anopheles darlingi, An. oswaldoi (s.l., An. triannulatus (s.s. and An. mattogrossensis were primarily found in larval habitats that were partially or mostly sun-exposed. In contrast, An. costai-like and An. guarao-like mosquitoes were found in more shaded aquatic habitats. Anopheles darlingi was significantly associated with proximity to human habitations and larval habitats associated with river flood pulses and clear water. Conclusions This study of anopheline larvae in the Brazilian Yanomami area detected high heterogeneities at micro-scale levels regarding species occurrence and densities. Sun exposure was a major modulator of anopheline occurrence, particularly for An. darlingi. Lakes associated with the rivers, and particularly oxbow lakes, were the main larval habitats for An. darlingi and other secondary malaria vectors. The results of this study will serve as a

  11. Effects of dimensional size and surface roughness on service performance for a micro Laval nozzle

    International Nuclear Information System (INIS)

    Cai, Yukui; Liu, Zhanqiang; Shi, Zhenyu

    2017-01-01

    Nozzles with large and small dimensions are widely used in various industries. The main objective of this research is to investigate the effects of dimensional size and surface roughness on the service performance of a micro Laval nozzle. The variation of nozzle service performance from the conventional macro to micro scale is presented in this paper. This shows that the dimensional nozzle size has a serious effect on the nozzle gas flow friction. With the decrease of nozzle size, the velocity performance and thrust performance deteriorate. The micro nozzle performance has less sensitivity to the variation of surface roughness than the large scale nozzle does. Surface quality improvement and burr prevention technologies are proposed to reduce the friction effect on the micro nozzle performance. A novel process is then developed to control and depress the burr generation during micro nozzle machining. The polymethyl-methacrylate as a coating material is coated on the rough machined surface before finish machining. Finally, the micro nozzle with a throat diameter of 1 mm is machined successfully. Thrust test results show that the implement and application of this machining process benefit the service performance improvement of the micro nozzle. (paper)

  12. Nuclear reactor fuel assembly with a removable top nozzle

    International Nuclear Information System (INIS)

    Shallenberger, J.M.; Ferlan, S.J.

    1986-01-01

    This patent describes a fuel assembly having at least one control rod guide thimble and a top nozzle, the top nozzle including a transversely extending adapter plate. An improved attaching structure is described for removably mounting the top nozzle on the guide thimble comprising: (a) means defining an outer socket in the top nozzle, the outer socket defining means including a passageway extending through the adapter plate and having a first mating element defined in the adapter plate within the passageway; (b) means on an upper end of the guide thimble defining an inner socket, the inner socket defining means including an elongated sleeve having an upper end portion. The upper end portion of the sleeve has a second mating element formed thereon and at least one elongated axial slot defined therein for permitting radial movement of the sleeve upper end portion between a compressed releasing position for removing and inserting the inner socket from and into the outer socket and an expanded locking position for locking the inner and outer sockets together

  13. SHINE Tritium Nozzle Design: Activity 6, Task 1 Report

    Energy Technology Data Exchange (ETDEWEB)

    Okhuysen, Brett S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pulliam, Elias Noel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-05

    In FY14, we studied the qualitative and quantitative behavior of a SHINE/PNL tritium nozzle under varying operating conditions. The result is an understanding of the nozzle’s performance in terms of important flow features that manifest themselves under different parametric profiles. In FY15, we will consider nozzle design with a focus on nozzle geometry and integration. From FY14 work, we will understand how the SHINE/PNL nozzle behaves under different operating scenarios. The first task for FY15 is to evaluate the FY14 model as a predictor of the actual flow. Considering different geometries is more time-intensive than parameter studies, therefore we recommend considering any relevant flow features that were not included in the FY14 model. In the absence of experimental data, it is particularly important to consider any sources of heat in the domain or boundary conditions that may affect the flow and incorporate these into the simulation if they are significant. Additionally, any geometric features of the beamline segment should be added to the model such as the orifice plate. The FY14 model works with hydrogen. An improvement that can be made for FY15 is to develop CFD properties for tritium and incorporate those properties into the new models.

  14. Calibration of nozzle for air mass flow measurement

    Science.gov (United States)

    Uher, Jan; Kanta, Lukáš

    2017-09-01

    The effort to make calibration measurement of mass flow through a nozzle was not satisfying. Traversing across the pipe radius with Pitot probe was done. The presence of overshoot behind the bend in the pipe was found. The overshoot led to an asymmetric velocity profile.

  15. 46 CFR 181.320 - Fire hoses and nozzles.

    Science.gov (United States)

    2010-10-01

    ... fittings of brass or other suitable corrosion-resistant material that comply with NFPA 1963 (incorporated..., and an outer cover of rubber or equivalent material, and of sufficient strength to withstand the... corrosion-resistant material. (d) Each nozzle must be of corrosion-resistant material and be capable of...

  16. The separation nozzle process for uranium isotope enrichment

    International Nuclear Information System (INIS)

    Becker, E.W.

    1977-01-01

    In the separation nozzle process, uranium isotope separation is brought about by the mass dependence of the centrifugal forces in a curved flow of a UF 6 /H 2 -mixture. Due to the large excess in hydrogen the high ration of UF 6 flow velocity to thermal velocity required for an effective isotope separation is obtained at relatively low expansion ratios and, accordingly, with relatively low gas-dynamic losses. As the optimum Reynolds number of the curved jet is comparatively low and a high absolute pressure is essential for economic reasons, the characteristic dimensions of the nozzle systems are made as small as possible. For commercial application in the near future systems involving mechanical jet deflection were developed. However, promising results were also obtained with separation nozzle systems generating a streamline curvature by the interaction of opposed jets. Most of the development work has been done at the Nuclear Research Center of Karlsruhe. Since 1970 the German company STEAG has been involved in the commercial implementation of the process. Two industrial-scale separative stages were tested successfully. This work constitutes the basis of planning of a separation nozzle demonstration plant to be built in Brazil

  17. Separation of finest dusts in Venturi scrubber with hybrid nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Reither, K. [Reither Venturiwaescher GmbH, Troisdorf (Germany); Boerger, G.G.; Listner, U.; Schweitzer, M. [Bayer AG, Leverkusen (Germany)

    2001-03-01

    Venturi scrubbers are high-performance dust separators whose efficiency is closely connected with high pressure losses. The tube-slot Venturi scrubber with hybrid nozzles is a novel scrubber type of simple and compact design, by means of which high separation efficiency is reached with pressure losses practically tending to zero. This new wet scrubber is particularly suitable for refitting existing plants. (orig.)

  18. The jet nozzle process for uranium 235 isotopic enrichment

    International Nuclear Information System (INIS)

    Jordan, I.; Umeda, K.; Brown, A.E.P.

    1979-01-01

    A general survey of the isotopic enrichment of Uranium - 235, principally by jet nozzle process, is made. Theoretical treatment of a single stage and cascade of separation stages of the above process with its development in Germany until 1976 is presented [pt

  19. Design and Analysis of Elliptical Nozzle in AJM Process using ...

    African Journals Online (AJOL)

    Abrasive jet machining (AJM) is a micromachining process, where material is removed from the work piece by the erosion effect of a high speed stream of abrasive particles carried in a gas medium, which are emerging from a nozzle. Abrasive machining includes grinding super finishing honing, lapping polishing etc.

  20. Ayame/PAM-D apogee kick motor nozzle failure analysis

    Science.gov (United States)

    1981-01-01

    The failure of two communication satellites during firing sequence were examined. The correlation/comparison of the circumstances of the Ayame incidents and the failure of the STAR 48 (DM-2) motor are reviewed. The massive nozzle failure of the AKM to determine the impact on spacecraft performance is examined. It is recommended that a closer watch is kept on systems techniques,

  1. Development of rapid mixing fuel nozzle for premixed combustion

    International Nuclear Information System (INIS)

    Katsuki, Masashi; Chung, Jin Do; Kim, Jang Woo; Hwang, Seung Min; Kim, Seung Mo; Ahn, Chul Ju

    2009-01-01

    Combustion in high-preheat and low oxygen concentration atmosphere is one of the attractive measures to reduce nitric oxide emission as well as greenhouse gases from combustion devices, and it is expected to be a key technology for the industrial applications in heating devices and furnaces. Before proceeding to the practical applications, we need to elucidate combustion characteristics of non-premixed and premixed flames in high-preheat and low oxygen concentration conditions from scientific point of view. For the purpose, we have developed a special mixing nozzle to create a homogeneous mixture of fuel and air by rapid mixing, and applied this rapidmixing nozzle to a Bunsen-type burner to observe combustion characteristics of the rapid-mixture. As a result, the combustion of rapid-mixture exhibited the same flame structure and combustion characteristics as the perfectly prepared premixed flame, even though the mixing time of the rapid-mixing nozzle was extremely short as a few milliseconds. Therefore, the rapid-mixing nozzle in this paper can be used to create preheated premixed flames as far as the mixing time is shorter than the ignition delay time of the fuel

  2. High-Melt Carbon-Carbon Coating for Nozzle Extensions

    Science.gov (United States)

    Thompson, James

    2015-01-01

    Carbon-Carbon Advanced Technologies, Inc. (C-CAT), has developed a high-melt coating for use in nozzle extensions in next-generation spacecraft. The coating is composed primarily of carbon-carbon, a carbon-fiber and carbon-matrix composite material that has gained a spaceworthy reputation due to its ability to withstand ultrahigh temperatures. C-CAT's high-melt coating embeds hafnium carbide (HfC) and zirconium diboride (ZrB2) within the outer layers of a carbon-carbon structure. The coating demonstrated enhanced high-temperature durability and suffered no erosion during a test in NASA's Arc Jet Complex. (Test parameters: stagnation heat flux=198 BTD/sq ft-sec; pressure=.265 atm; temperature=3,100 F; four cycles totaling 28 minutes) In Phase I of the project, C-CAT successfully demonstrated large-scale manufacturability with a 40-inch cylinder representing the end of a nozzle extension and a 16-inch flanged cylinder representing the attach flange of a nozzle extension. These demonstrators were manufactured without spalling or delaminations. In Phase II, C-CAT worked with engine designers to develop a nozzle extension stub skirt interfaced with an Aerojet Rocketdyne RL10 engine. All objectives for Phase II were successfully met. Additional nonengine applications for the coating include thermal protection systems (TPS) for next-generation spacecraft and hypersonic aircraft.

  3. Area-Selective ZnO Thin Film Deposition on Variable Microgap Electrodes and Their Impact on UV Sensing

    Directory of Open Access Journals (Sweden)

    Q. Humayun

    2013-01-01

    Full Text Available ZnO thin films were deposited on patterned gold electrodes using the sol-gel spin coating technique. Conventional photolithography process was used to obtain the variable microgaps of 30 and 43 μm in butterfly topology by using zero-gap chrome mask. The structural, morphological, and electrical properties of the deposited thin films were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, and Keithley SourceMeter, respectively. The current-voltage (I-V characterization was performed to investigate the effect of UV light on the fabricated devices. The ZnO fabricated sensors showed a photo to dark current (Iph/Id ratios of 6.26 for 30 μm and 5.28 for 43 μm gap electrodes spacing, respectively. Dynamic responses of both fabricated sensors were observed till 1V with good reproducibility. At the applied voltage of 1 V, the response time was observed to be 4.817 s and 3.704 s while the recovery time was observed to be 0.3738 s and 0.2891 s for 30 and 43 μm gaps, respectively. The signal detection at low operating voltages suggested that the fabricated sensors could be used for miniaturized devices with low power consumption.

  4. Supersonic propulsion technology. [variable cycle engines

    Science.gov (United States)

    Powers, A. G.; Coltrin, R. E.; Stitt, L. E.; Weber, R. J.; Whitlow, J. B., Jr.

    1979-01-01

    Propulsion concepts for commercial supersonic transports are discussed. It is concluded that variable cycle engines, together with advanced supersonic inlets and low noise coannular nozzles, provide good operating performance for both supersonic and subsonic flight. In addition, they are reasonably quiet during takeoff and landing and have acceptable exhaust emissions.

  5. Geophysical variables and behavior: LIII. Epidemiological considerations for incidence of cancer and depression in areas of frequent UFO reports.

    Science.gov (United States)

    Persinger, M A

    1988-12-01

    Luminous phenomena and anomalous physical forces have been hypothesized to be generated by focal tectonic strain fields that precede earthquakes. If these geophysical processes exist, then their spatial and temporal density should be greatest during periods of protracted, localized UFO reports; they might be used as dosimetric indicators. Contemporary epidemiological data concerning the health risks of power frequency electromagnetic fields and radon gas levels (expected correlates of certain tectonic strain fields), suggest that increased incidence (odds ratios greater 1:3) of brain tumors and leukemia should be evident within "flap" areas. In addition the frequency of variants of temporal lobe lability, psychological depression and posttraumatic stress should be significantly elevated. UFO field investigators, because they have repeated, intermittent close proximity to these fields, are considered to be a particularly high risk population for these disorders.

  6. Geophysical variables and behavior: LIII. Epidemiological considerations for incidence of cancer and depression in areas of frequent UFO reports

    International Nuclear Information System (INIS)

    Persinger, M.A.

    1988-01-01

    Luminous phenomena and anomalous physical forces have been hypothesized to be generated by focal tectonic strain fields that precede earthquakes. If these geophysical processes exist, then their spatial and temporal density should be greatest during periods of protracted, localized UFO reports; they might be used as dosimetric indicators. Contemporary epidemiological data concerning the health risks of power frequency electromagnetic fields and radon gas levels (expected correlates of certain tectonic strain fields), suggest that increased incidence (odds ratios greater 1:3) of brain tumors and leukemia should be evident within flap areas. In addition the frequency of variants of temporal lobe lability, psychological depression and posttraumatic stress should be significantly elevated. UFO field investigators, because they have repeated, intermittent close proximity to these fields, are considered to be a particularly high risk population for these disorders. 22 references

  7. Representation of fine scale atmospheric variability in a nudged limited area quasi-geostrophic model: application to regional climate modelling

    Science.gov (United States)

    Omrani, H.; Drobinski, P.; Dubos, T.

    2009-09-01

    In this work, we consider the effect of indiscriminate nudging time on the large and small scales of an idealized limited area model simulation. The limited area model is a two layer quasi-geostrophic model on the beta-plane driven at its boundaries by its « global » version with periodic boundary condition. This setup mimics the configuration used for regional climate modelling. Compared to a previous study by Salameh et al. (2009) who investigated the existence of an optimal nudging time minimizing the error on both large and small scale in a linear model, we here use a fully non-linear model which allows us to represent the chaotic nature of the atmosphere: given the perfect quasi-geostrophic model, errors in the initial conditions, concentrated mainly in the smaller scales of motion, amplify and cascade into the larger scales, eventually resulting in a prediction with low skill. To quantify the predictability of our quasi-geostrophic model, we measure the rate of divergence of the system trajectories in phase space (Lyapunov exponent) from a set of simulations initiated with a perturbation of a reference initial state. Predictability of the "global", periodic model is mostly controlled by the beta effect. In the LAM, predictability decreases as the domain size increases. Then, the effect of large-scale nudging is studied by using the "perfect model” approach. Two sets of experiments were performed: (1) the effect of nudging is investigated with a « global » high resolution two layer quasi-geostrophic model driven by a low resolution two layer quasi-geostrophic model. (2) similar simulations are conducted with the two layer quasi-geostrophic LAM where the size of the LAM domain comes into play in addition to the first set of simulations. In the two sets of experiments, the best spatial correlation between the nudge simulation and the reference is observed with a nudging time close to the predictability time.

  8. Mathematical Investigation of the Cavitation Phenomenon in the Nozzle with Partially Surface Wetting

    Directory of Open Access Journals (Sweden)

    Jablonská Jana

    2015-12-01

    Full Text Available Partially surface wetting has a great influence on friction losses in the fluid flow in both the pipeline system and the complex shape of hydraulic elements. In many hydraulic elements (valves, pump impellers, cavitation is generated, which significantly changes the hydraulic flow parameters, so the last part of the article is devoted to the mathematical solution of this phenomena and evaluates the impact of wall wetting on the size and shape of the cavitation area which appears in the nozzle and in small gaps at special conditions. If the cavitation appears e. g. near the wall of pipes, the blades of turbine or a pump, then it destroys the material surface. On the basis of this physical experiment (nozzle, a two-dimensional (2D mathematical cavitation model of Schnerr-Sauer was made and calculated shape and size of the cavitation region was compared with the experiment. Later this verified model of cavitation was used for cavitation research flow with partial surface wetting. The pressure drop and the size of the cavitation area as it flows from partially surface wetting theory was tested depending on the adhesion coefficient.

  9. Heat exchanger nozzle stresses due to pipe vibration

    International Nuclear Information System (INIS)

    Wolgemuth, G.A.

    1983-01-01

    A large diameter pipe in a heavy water production plant was excited into a low frequency vibration due to void collapse of the pipe contents at a sharp vertical drop in the pipe run. Fears that this vibration would fatigue the inlet nozzle to the heat exchanger prompted the introduction of a flow of cold water into the pipe to prevent the two-phase flow from developing but at the cost of reduced heat exchanger efficiency. An investigation was carried out to determine the stress levels in the nozzle with the quenching flow off and suggest means of reducing them if excessive. A finite element dynamic simulation of the pipe run was performed to determine the likely mode shapes. This information was used to optimize the placement of velocity probes on the pipe. Field measurements of vibration were taken for several operating conditions. This data was analyzed and the results used to refine the support stiffness used in the finite element simulation. The finite element model was then used to predict the nozzle forces and moments. In turn this data was used to determine the local stresses in the nozzle. The ASME Section III code was used to determine the allowable fully reversing stresses for the unit in question. It was found that the endurance limit of 83 MPa was exceeded in the analysis only when using the most conservative estimates for each uncertainty. It was recommended that if the safety factor was not deemed high enough, the nozzle should be built up with a reinforcing pad no thicker than 12 mm

  10. Vortex flow and cavitation in diesel injector nozzles

    Science.gov (United States)

    Andriotis, A.; Gavaises, M.; Arcoumanis, C.

    Flow visualization as well as three-dimensional cavitating flow simulations have been employed for characterizing the formation of cavitation inside transparent replicas of fuel injector valves used in low-speed two-stroke diesel engines. The designs tested have incorporated five-hole nozzles with cylindrical as well as tapered holes operating at different fixed needle lift positions. High-speed images have revealed the formation of an unsteady vapour structure upstream of the injection holes inside the nozzle volume, which is referred to as . Computation of the flow distribution and combination with three-dimensional reconstruction of the location of the strings inside the nozzle volume has revealed that strings are found at the core of recirculation zones; they originate either from pre-existing cavitation sites forming at sharp corners inside the nozzle where the pressure falls below the vapour pressure of the flowing liquid, or even from suction of outside air downstream of the hole exit. Processing of the acquired images has allowed estimation of the mean location and probability of appearance of the cavitating strings in the three-dimensional space as a function of needle lift, cavitation and Reynolds number. The frequency of appearance of the strings has been correlated with the Strouhal number of the vortices developing inside the sac volume; the latter has been found to be a function of needle lift and hole shape. The presence of strings has significantly affected the flow conditions at the nozzle exit, influencing the injected spray. The cavitation structures formed inside the injection holes are significantly altered by the presence of cavitation strings and are jointly responsible for up to 10% variation in the instantaneous fuel injection quantity. Extrapolation using model predictions for real-size injectors operating at realistic injection pressures indicates that cavitation strings are expected to appear within the time scales of typical injection

  11. Structure of the gas-liquid annular two-phase flow in a nozzle section

    International Nuclear Information System (INIS)

    Yoshida, Kenji; Kataoka, Isao; Ohmori, Syuichi; Mori, Michitsugu

    2006-01-01

    Experimental studies on the flow behavior of gas-liquid annular two-phase flow passing through a nozzle section were carried out. This study is concerned with the central steam jet injector for a next generation nuclear reactor. In the central steam jet injector, steam/water annular two-phase flow is formed at the mixing nozzle. To make an appropriate design and to establish the high-performance steam injector system, it is very important to accumulate the fundamental data of the thermo-hydro dynamic characteristics of annular flow passing through a nozzle section. On the other hand, the transient behavior of multiphase flow, in which the interactions between two-phases occur, is one of the most interesting scientific issues and has attracted research attention. In this study, the transient gas-phase turbulence modification in annular flow due to the gas-liquid phase interaction is experimentally investigated. The annular flow passing through a throat section is under the transient state due to the changing cross sectional area of the channel and resultantly the superficial velocities of both phases are changed compared with a fully developed flow in a straight pipe. The measurements for the gas-phase turbulence were precisely performed by using a constant temperature hot-wire anemometer, and made clear the turbulence structure such as velocity profiles, fluctuation velocity profiles. The behavior of the interfacial waves in the liquid film flow such as the ripple or disturbance waves was also observed. The measurements for the liquid film thickness by the electrode needle method were also performed to measure the base film thickness, mean film thickness, maximum film thickness and wave height of the ripple or the disturbance waves. (author)

  12. Association of Lutzomyia longipalpis (Diptera: Psychodidae population density with climate variables in Montes Claros, an area of American visceral leishmaniasis transmission in the state of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Érika Monteiro Michalsky

    2009-12-01

    Full Text Available In the present paper, we evaluate the relationship between climate variables and population density of Lutzomyia longipalpis in Montes Claros, an area of active transmission of American visceral leishmaniasis (AVL in Brazil. Entomological captures were performed in 10 selected districts of the city, between September 2002-August 2003. A total of 773 specimens of L. longipalpiswere captured in the period and the population density could be associated with local climate variables (cumulative rainfall, average temperature and relative humidity through a mathematical linear model with a determination coefficient (Rsqr of 0.752. Although based on an oversimplified statistical analysis, as far as the vector is concerned, this approach showed to be potentially useful as a starting point to guide control measures for AVL in Montes Claros.

  13. Association of Lutzomyia longipalpis (Diptera: Psychodidae) population density with climate variables in Montes Claros, an area of American visceral leishmaniasis transmission in the state of Minas Gerais, Brazil.

    Science.gov (United States)

    Michalsky, Erika Monteiro; Fortes-Dias, Consuelo Latorre; França-Silva, João Carlos; Rocha, Marilia Fonseca; Barata, Ricardo Andrade; Dias, Edelberto Santos

    2009-12-01

    In the present paper, we evaluate the relationship between climate variables and population density of Lutzomyia longipalpis in Montes Claros, an area of active transmission of American visceral leishmaniasis (AVL) in Brazil. Entomological captures were performed in 10 selected districts of the city, between September 2002-August 2003. A total of 773 specimens of L. longipalpiswere captured in the period and the population density could be associated with local climate variables (cumulative rainfall, average temperature and relative humidity) through a mathematical linear model with a determination coefficient (Rsqr) of 0.752. Although based on an oversimplified statistical analysis, as far as the vector is concerned, this approach showed to be potentially useful as a starting point to guide control measures for AVL in Montes Claros.

  14. Failure analysis of the Ringhals unit 3 EDM surfaces removed from the RPV outlet nozzle to safe end weld

    International Nuclear Information System (INIS)

    Efsing, Pal; Embring, Goeran; Forssgren, Bjoern; Kroes, Bert; Lundstroem, Roger

    2006-09-01

    During the 2000 RFO (Re-Fueling Outage) In-Service Inspection of the nozzle to safe end weld of the Hot Leg Reactor Pressure Vessel Nozzles in Ringhals 3 and 4, axially oriented defects in the Alloy 182 weld metal were detected. In the case of Ringhals 3, the defects were initially considered as being embedded and thus left for future consideration, whereas the defects in Ringhals 4 were judged as being surface breaking and removed by EDM (Electro Discharge Machining). During the RFO 2001, the defects in Ringhals 3 were also removed by EDM without applying any surface treatment subsequent to the sampling. The cavities were inspected using a standard ET technique for manufacturing control before the plant was allowed to return to service. After one cycle of operation, the cavities resulting from the boat sampling were inspected by ET and UT techniques and indications of renewed, shallow cracking were identified. The indications were pre-dominantly axially oriented, of limited depth and with surface breaking lengths varying from 4 to 18 mm. To investigate the cause of this cracking, it was decided to remove a second series of small boat samples from the areas with indications, prior to implementation of a permanent repair. To minimize the impact on the RFO schedule and the material loss that would have resulted from EDM boat sample removal, mini samples were removed manually, using a small axial grinder. The sampling was performed after nozzle decontamination and used a dry nozzle access system that had been specifically developed for the nozzle repair. The sample removal was completed in approximately two hours and a total of three samples were shipped to the Studsvik hot cell laboratories for failure analysis. The failure analysis revealed a typical surface morphology, resulting from the EDM process and confirmed that numerous micro-fissures may result from the process if it is utilized without proper optimization and care. On one of the boat samples, surface areas

  15. Present and past Gulf Stream variability in a cold-water coral area off Cape Lookout, West Atlantic

    Science.gov (United States)

    Mienis, F.; Pedersen, A.; Duineveld, G.; Seidenkrantz, M.; Fischel, A.; Matos, L.; Bane, J. M.; Frank, N.; Hebbeln, D.; Ross, S.

    2012-12-01

    Cold-water coral mounds are common on the SE slope of the US from Florida to Cape Hatteras between depths of 400-600 m. All coral areas lie in the vicinity of the Gulf Stream, which is characterized by strong currents transporting relatively warm water northwards. Thus far little is known about the recent and past environmental conditions inside the cold-water coral habitats on the SE US slope and particularly the effect of changing patterns of the Gulf Stream. Near Cape Lookout, which is the northern most cold-water coral area on the SE US slope, cold-water corals have formed mounds up to 60 m high with a tear drop shape, which are oriented in a SSW-NNE direction. Past explorations of major reef sites of N Carolina using remote and manned submersibles have shown living Lophelia pertusa colonies on the current facing side of the mound structures and a high biodiversity of associated fauna, especially fish. Two autonomous benthic landers were deployed amidst Lophelia reefs off Cape Lookout (NC) for a period of 6 months to define oceanographic patterns that are relevant for the development and persistence of cold-water coral ecosystems. Furthermore, a 3.6 m long piston core was collected in 2010 during a cruise with the R.V. Pelagia. This pistoncore was used to determine the changes of current strength through time, using foraminiferal counts, stable oxygen and carbon isotopes on foraminifera, XRF and magnetic susceptibility measurements. Cold-water coral fragments were dated with U/Th and foraminifera from the same depth interval were dated with C14. Bottom landers have recorded a number of events that are characterized by of peaks in temperature and salinity, coinciding with increased flow and turbidity. The current during these events was directed to the NNE. During some of these events temperature rose up to 9 degrees in one day. The temporary replacement of the colder bottom water by warm (and saline) water in combination with the strong currents to the NNE

  16. Multilaboratory particle image velocimetry analysis of the FDA benchmark nozzle model to support validation of computational fluid dynamics simulations.

    Science.gov (United States)

    Hariharan, Prasanna; Giarra, Matthew; Reddy, Varun; Day, Steven W; Manning, Keefe B; Deutsch, Steven; Stewart, Sandy F C; Myers, Matthew R; Berman, Michael R; Burgreen, Greg W; Paterson, Eric G; Malinauskas, Richard A

    2011-04-01

    This study is part of a FDA-sponsored project to evaluate the use and limitations of computational fluid dynamics (CFD) in assessing blood flow parameters related to medical device safety. In an interlaboratory study, fluid velocities and pressures were measured in a nozzle model to provide experimental validation for a companion round-robin CFD study. The simple benchmark nozzle model, which mimicked the flow fields in several medical devices, consisted of a gradual flow constriction, a narrow throat region, and a sudden expansion region where a fluid jet exited the center of the nozzle with recirculation zones near the model walls. Measurements of mean velocity and turbulent flow quantities were made in the benchmark device at three independent laboratories using particle image velocimetry (PIV). Flow measurements were performed over a range of nozzle throat Reynolds numbers (Re(throat)) from 500 to 6500, covering the laminar, transitional, and turbulent flow regimes. A standard operating procedure was developed for performing experiments under controlled temperature and flow conditions and for minimizing systematic errors during PIV image acquisition and processing. For laminar (Re(throat)=500) and turbulent flow conditions (Re(throat)≥3500), the velocities measured by the three laboratories were similar with an interlaboratory uncertainty of ∼10% at most of the locations. However, for the transitional flow case (Re(throat)=2000), the uncertainty in the size and the velocity of the jet at the nozzle exit increased to ∼60% and was very sensitive to the flow conditions. An error analysis showed that by minimizing the variability in the experimental parameters such as flow rate and fluid viscosity to less than 5% and by matching the inlet turbulence level between the laboratories, the uncertainties in the velocities of the transitional flow case could be reduced to ∼15%. The experimental procedure and flow results from this interlaboratory study (available

  17. Vulnerability Assessment of Mangrove Habitat to the Variables of the Oceanography Using CVI Method (Coastal Vulnerability Index) in Trimulyo Mangrove Area, Genuk District, Semarang

    Science.gov (United States)

    Ahmad, Rifandi Raditya; Fuad, Muhammad

    2018-02-01

    Some functions of mangrove areas in coastal ecosystems as a green belt, because mangrove serves as a protector of the beach from the sea waves, as a good habitat for coastal biota and for nutrition supply. Decreased condition or degradation of mangrove habitat caused by several oceanographic factors. Mangrove habitats have some specific characteristics such as salinity, tides, and muddy substrates. Considering the role of mangrove area is very important, it is necessary to study about the potential of mangrove habitat so that the habitat level of mangrove habitat in the east coast of Semarang city is known. The purpose of this research is to obtain an index and condition of habitat of mangrove habitat at location of research based on tidal, salinity, substrate type, coastline change. Observation by using purposive method and calculation of habitat index value of mangrove habitat using CVI (Coastal Vulnerability Index) method with scores divided into 3 groups namely low, medium and high. The results showed that there is a zone of research belonging to the medium vulnerability category with the most influential variables is because there is abrasion that sweeps the mangrove substrate. Trimulyo mangrove habitat has high vulnerable variable of tidal frequency, then based on value variable Salinity is categorized as low vulnerability, whereas for mangrove habitat vulnerability based on variable type of substrate belong to low and medium vulnerability category. The CVI values of mangrove habitats divided into zones 1; 2; and 3 were found to varying values of 1.54; 3.79; 1.09, it indicates that there is a zone with the vulnerability of mangrove habitat at the study site belonging to low and medium vulnerability category.

  18. Phytoplankton variability and community structure in relation to hydrographic features in the NE Aegean frontal area (NE Mediterranean Sea)

    Science.gov (United States)

    Lagaria, A.; Mandalakis, M.; Mara, P.; Frangoulis, C.; Karatsolis, B.-Th.; Pitta, P.; Triantaphyllou, M.; Tsiola, A.; Psarra, S.

    2017-10-01

    The structure of phytoplankton community in the salinity-stratified Northeastern Aegean frontal area adjacent to the Dardanelles Straits was investigated on a seasonal basis (autumn, spring and summer) and in relation to circulating water masses: the modified Black Sea Water (BSW) and the Levantine Water (LW). By employing High Performance Liquid Chromatography (HPLC) for the analysis of phytoplankton pigments in conjunction with conventional cell counting methodologies (i.e. inverted light microscopy, flow cytometry) and primary production measurements, a comprehensive qualitative and quantitative characterization of phytoplankton community composition and its activity was conducted. Chlorophyll-a normalized production and estimated growth rates presented the highest values within the 'fresh' BSW mass during summer, though generally growth rates were low (production. Large cell organisms, and in particular diatoms, were closely associated with the surface BSW masses outflowing from the Straits. Our results showed that all phytoplankton size components were significant over time and space suggesting a rather multivorous food web functioning of the system.

  19. Variability of the groundwater sulfate concentration in fractured rock slopes: a tool to identify active unstable areas

    Directory of Open Access Journals (Sweden)

    S. Binet

    2009-12-01

    Full Text Available Water chemical analysis of 100 springs from the Orco and the Tinée valleys (Western Italy and Southern France and a 7 year groundwater chemistry monitoring of the 5 main springs were performed. All these springs drain from crystalline rock slopes. Some of these drain from currently active gravitational slope deformations.

    All groundwaters flowing through presently unstable slopes show anomalies in the sulfate concentrations compared to stable aquifers. Particularly, an increase of sulfate concentrations was observed repeatedly after each of five consecutive landslides on the La Clapière slope, thus attesting to the mechanical deformations are at the origin of this concentration change. Significant changes in the water chemistry are produced even from slow (mm/year and low magnitude deformations of the geological settings.

    Pyrite nuclei in open fractures were found to be coated by iron oxides. This suggests that the increase of dissolved sulfate relates to oxidative dissolution of Pyrite. Speciation calculations of Pyrite versus Gypsum confirmed that observed changes in the sulfate concentrations is predominantly provided from Pyrite. Calculated amounts of dissolved minerals in the springs water was obtained through inverse modelling of the major ion water analysis data. It is shown that the concentration ratio of calculated dissolved Pyrite versus calculated dissolved gneiss rock allows us to unambiguously distinguish water from stable and unstable areas. This result opens an interesting perspective for the follow-up of sliding or friction dynamic in landslides or in (a seismic faults.

  20. Turbine combustor with fuel nozzles having inner and outer fuel circuits

    Science.gov (United States)

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo

    2013-12-24

    A combustor cap assembly for a turbine engine includes a combustor cap and a plurality of fuel nozzles mounted on the combustor cap. One or more of the fuel nozzles would include two separate fuel circuits which are individually controllable. The combustor cap assembly would be controlled so that individual fuel circuits of the fuel nozzles are operated or deliberately shut off to provide for physical separation between the flow of fuel delivered by adjacent fuel nozzles and/or so that adjacent fuel nozzles operate at different pressure differentials. Operating a combustor cap assembly in this fashion helps to reduce or eliminate the generation of undesirable and potentially harmful noise.

  1. Integration of Flex Nozzle System and Electro Hydraulic Actuators to Solid Rocket Motors

    Science.gov (United States)

    Nayani, Kishore Nath; Bajaj, Dinesh Kumar

    2017-10-01

    A rocket motor assembly comprised of solid rocket motor and flex nozzle system. Integration of flex nozzle system and hydraulic actuators to the solid rocket motors are done after transportation to the required place where integration occurred. The flex nozzle system is integrated to the rocket motor in horizontal condition and the electro hydraulic actuators are assembled to the flex nozzle systems. The electro hydraulic actuators are connected to the hydraulic power pack to operate the actuators. The nozzle-motor critical interface are insulation diametrical compression, inhibition resin-28, insulation facial compression, shaft seal `O' ring compression and face seal `O' ring compression.

  2. System and method having multi-tube fuel nozzle with differential flow

    Science.gov (United States)

    Hughes, Michael John; Johnson, Thomas Edward; Berry, Jonathan Dwight; York, William David

    2017-01-03

    A system includes a multi-tube fuel nozzle with a fuel nozzle body and a plurality of tubes. The fuel nozzle body includes a nozzle wall surrounding a chamber. The plurality of tubes extend through the chamber, wherein each tube of the plurality of tubes includes an air intake portion, a fuel intake portion, and an air-fuel mixture outlet portion. The multi-tube fuel nozzle also includes a differential configuration of the air intake portions among the plurality of tubes.

  3. Area- and depth- weighted averages of selected SSURGO variables for the conterminous United States and District of Columbia

    Science.gov (United States)

    Wieczorek, Michael

    2014-01-01

    This digital data release consists of seven data files of soil attributes for the United States and the District of Columbia. The files are derived from National Resources Conservations Service’s (NRCS) Soil Survey Geographic database (SSURGO). The data files can be linked to the raster datasets of soil mapping unit identifiers (MUKEY) available through the NRCS’s Gridded Soil Survey Geographic (gSSURGO) database (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053628). The associated files, named DRAINAGECLASS, HYDRATING, HYDGRP, HYDRICCONDITION, LAYER, TEXT, and WTDEP are area- and depth-weighted average values for selected soil characteristics from the SSURGO database for the conterminous United States and the District of Columbia. The SSURGO tables were acquired from the NRCS on March 5, 2014. The soil characteristics in the DRAINAGE table are drainage class (DRNCLASS), which identifies the natural drainage conditions of the soil and refers to the frequency and duration of wet periods. The soil characteristics in the HYDRATING table are hydric rating (HYDRATE), a yes/no field that indicates whether or not a map unit component is classified as a "hydric soil". The soil characteristics in the HYDGRP table are the percentages for each hydrologic group per MUKEY. The soil characteristics in the HYDRICCONDITION table are hydric condition (HYDCON), which describes the natural condition of the soil component. The soil characteristics in the LAYER table are available water capacity (AVG_AWC), bulk density (AVG_BD), saturated hydraulic conductivity (AVG_KSAT), vertical saturated hydraulic conductivity (AVG_KV), soil erodibility factor (AVG_KFACT), porosity (AVG_POR), field capacity (AVG_FC), the soil fraction passing a number 4 sieve (AVG_NO4), the soil fraction passing a number 10 sieve (AVG_NO10), the soil fraction passing a number 200 sieve (AVG_NO200), and organic matter (AVG_OM). The soil characteristics in the TEXT table are

  4. Effect of Orifice Nozzle Design and Input Power on Two-Phase Flow and Mass Transfer Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hei Cheon [Chonnam Nat’l Univ., Gwangju (Korea, Republic of)

    2016-04-15

    It is necessary to investigate the input power as well as the mass transfer characteristics of the aeration process in order to improve the energy efficiency of an aerobic water treatment. The objective of this study is to experimentally investigate the effect of orifice nozzle design and input power on the flow and mass transfer characteristics of a vertical two-phase flow. The mass ratio, input power, volumetric mass transfer coefficient, and mass transfer efficiency were calculated using the measured data. It was found that as the input power increases the volumetric mass transfer coefficient increases, while the mass ratio and mass transfer efficiency decrease. The mass ratio, volumetric mass transfer coefficient, and mass transfer efficiency were higher for the orifice configuration with a smaller orifice nozzle area ratio. An empirical correlation was proposed to estimate the effect of mass ratio, input power, and Froude number on the volumetric mass transfer coefficient.

  5. The proton therapy nozzles at Samsung Medical Center: A Monte Carlo simulation study using TOPAS

    Science.gov (United States)

    Chung, Kwangzoo; Kim, Jinsung; Kim, Dae-Hyun; Ahn, Sunghwan; Han, Youngyih

    2015-07-01

    To expedite the commissioning process of the proton therapy system at Samsung Medical Center (SMC), we have developed a Monte Carlo simulation model of the proton therapy nozzles by using TOol for PArticle Simulation (TOPAS). At SMC proton therapy center, we have two gantry rooms with different types of nozzles: a multi-purpose nozzle and a dedicated scanning nozzle. Each nozzle has been modeled in detail following the geometry information provided by the manufacturer, Sumitomo Heavy Industries, Ltd. For this purpose, the novel features of TOPAS, such as the time feature or the ridge filter class, have been used, and the appropriate physics models for proton nozzle simulation have been defined. Dosimetric properties, like percent depth dose curve, spreadout Bragg peak (SOBP), and beam spot size, have been simulated and verified against measured beam data. Beyond the Monte Carlo nozzle modeling, we have developed an interface between TOPAS and the treatment planning system (TPS), RayStation. An exported radiotherapy (RT) plan from the TPS is interpreted by using an interface and is then translated into the TOPAS input text. The developed Monte Carlo nozzle model can be used to estimate the non-beam performance, such as the neutron background, of the nozzles. Furthermore, the nozzle model can be used to study the mechanical optimization of the design of the nozzle.

  6. Seasonal and spatial variability of appendicularian density and taxonomic composition in the Caravelas Estuary (Northeastern Brazil and adjacent coastal area

    Directory of Open Access Journals (Sweden)

    Pedro Freitas de Carvalho

    2010-02-01

    Full Text Available This study aimed to identify and assess the seasonal and spatial variations of the appendicularians in the Caravelas River estuary and the adjacent coastal area. Samples were taken during 12 campaigns over five years (2001 and 2003-2006. Ten species were identified; the most abundant were Oikopleura dioica, Oikopleura rufescens, and Oikopleura longicauda. These species represented more than 95% of the total numbers of appendicularians. The remaining species were less frequent and occurred in low densities. The mean density of appendicularians found at the coastal stations (804 ind.m-3. was higher than in the estuary (66 ind.m-3. However, the differences observed between the estuary and coastal stations were not significant (p=0.54. The samples taken during the dry season showed a higher mean density (587 ind.m-3 than in the rainy season (376 ind.m-3, and the differences between the seasons were statistically significant (p=0.004.Esse trabalho teve como objetivo identificar e avaliar as variações espaciais e sazonais das apendiculárias no estuário do rio Caravelas e área costeira adjacente (17º35' - 18º22' S e 39º8' - 39º55'W. As coletas foram realizadas em 12 campanhas durante cinco anos (2001 e 2003 - 2006. Foram identificadas dez espécies, sendo que Oikopleura dioica, O. rufescens e O. longicauda foram as mais abundantes. Estas três espécies representaram mais de 95% do total de apendiculárias coletadas. As outras espécies foram menos freqüentes e ocorreram em baixas densidades. A densidade média de apendiculárias encontrada nas estações e costeiras (804 ind.m-3 foi maior que na de estuário (158 ind.m-3. As diferenças encontradas entre as estações de estuário e costeiras não foram significativas (p=0,73. As campanhas realizadas durante o período seco apresentaram densidade média (587 ind.m-3 maior que do período chuvoso (376 ind.m-3. As diferenças entre os períodos chuvoso e seco foram estatisticamente

  7. Atmospheric aerosol variability above the Paris Area during the 2015 heat wave - Comparison with the 2003 and 2006 heat waves

    Science.gov (United States)

    Chazette, Patrick; Totems, Julien; Shang, Xiaoxia

    2017-12-01

    The aerosol layers during the heat wave of July 2015 over Paris Area have been studied using a N2-Raman lidar with co- and cross-polarized channels. The lidar observations are examined to allow the identification of main aerosol types and their origins, in synergy with measurements of the AERONET sunphotometer network and back trajectory studies from the HYSPLIT model. The results are compatible with spaceborne observations of MODIS and CALIOP. As for previous heat waves of August 2003 and July 2006 occurring in France, the aerosol optical thickness is very large, up to 0.8 at the lidar wavelength of 355 nm (between 0.5 and 0.7 at 550 nm). However, air mass trajectories highlight that the observed aerosol layers may have multiple and diverse origins during the 2015 heat wave (North America, Northwest Africa, Southern and Northern Europe). Biomass burning, pollution and desert dust aerosols have been identified, using linear particle depolarization ratio, lidar ratio and analysis of back trajectories initiated at the altitudes and arrival times of the plumes. These layers are elevated and are shown to have little impact on surface aerosol concentrations (PM10 < 40 μg m-3 or PM2.5 < 25 μg m-3) and therefore no influence on the local air quality during the 2015 heat wave, unlike in 2003 and 2006. However, they significantly modify the radiative budget by trapping part of the solar ingoing/outgoing fluxes, which leads to a mean aerosol radiative forcing close to +50 ± 17 Wm-2 per aerosol optical thickness unit at 550 nm (AOT550) for solar zenith angles between 55 and 75°, which are available from sunphotometer measurements. This value is smaller than those of the 2003 and 2006 heat waves, which are assessed to be +95 ± 13 and +70 ± 18 Wm-2/AOT550, respectively. The differences between the heat wave of 2015 and the others are mainly due to both the nature and the diversity of aerosols, as indicated by the dispersion of the single scattering albedo distributions at

  8. A static investigation of yaw vectoring concepts on two-dimensional convergent-divergent nozzles

    Science.gov (United States)

    Berrier, B. L.; Mason, M. L.

    1983-01-01

    The flow-turning capability and nozzle internal performance of yaw-vectoring nozzle geometries were tested in the NASA Langley 16-ft Transonic wind tunnel. The concept was investigated as a means of enhancing fighter jet performance. Five two-dimensional convergent-divergent nozzles were equipped for yaw-vectoring and examined. The configurations included a translating left sidewall, left and right sidewall flaps downstream of the nozzle throat, left sidewall flaps or port located upstream of the nozzle throat, and a powered rudder. Trials were also run with 20 deg of pitch thrust vectoring added. The feasibility of providing yaw-thrust vectoring was demonstrated, with the largest yaw vector angles being obtained with sidewall flaps downstream of the nozzle primary throat. It was concluded that yaw vector designs that scoop or capture internal nozzle flow provide the largest yaw-vector capability, but decrease the thrust the most.

  9. Evaluation of an Experimental Model for Flat-Fan Nozzles Drift in Wind Tunnel by Image Processing

    Directory of Open Access Journals (Sweden)

    S.H Fattahi

    2014-09-01

    Full Text Available Each year, millions of liters of toxic liquid, are used to combat with pests and plant diseases in farms. The wide spread use of chemical pesticides causes great environmental hazards. Particles drift is one of the main problems in spraying which results in the contamination of farm lands, humans and animals. Management of particle size is regarded as the main factor in drift control. In this study, the effect of some parameters on the size of deposited particles on non-target areas was studied using statistical method. The effects of nozzle type (orifice size, spraying pressure, spraying boom height and wind speed as effective factors on drift were examined. A horizontal wind tunnel with working section of 0.47 m wide, 0.75 m height and 5.5 m long was used for testing. Experiment was performed in the form of factorial split-plot based on randomized complete block design with two replications. Droplets were measured in the treatment combinations of the type of flat-fan nozzle with three orifice area (11003- 0.87 mm2, 11004-1.18 mm2 and 11006- 1.8 mm2, spraying pressure (150, 275 and 400 kpa, wind speed (1, 2 and 3 m s-1 and the boom height of (0.35, 0.55 and 0.75 m. Water-sensitive papers were used at intervals of 0.8, 1.6 and 2.4 m from the tip of nozzles for detecting droplets size. The factors of pressure, speed and height had positive effects on the droplet size at the desired distance, but the effect of nozzle size on droplet size was negative. In the regression model the coefficients of speed was higher than the others.

  10. SINGLE PHASE ANALYTICAL MODELS FOR TERRY TURBINE NOZZLE

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haihua; Zhang, Hongbin; Zou, Ling; O' Brien, James

    2016-11-01

    All BWR RCIC (Reactor Core Isolation Cooling) systems and PWR AFW (Auxiliary Feed Water) systems use Terry turbine, which is composed of the wheel with turbine buckets and several groups of fixed nozzles and reversing chambers inside the turbine casing. The inlet steam is accelerated through the turbine nozzle and impacts on the wheel buckets, generating work to drive the RCIC pump. As part of the efforts to understand the unexpected “self-regulating” mode of the RCIC systems in Fukushima accidents and extend BWR RCIC and PWR AFW operational range and flexibility, mechanistic models for the Terry turbine, based on Sandia National Laboratories’ original work, has been developed and implemented in the RELAP-7 code to simulate the RCIC system. RELAP-7 is a new reactor system code currently under development with the funding support from U.S. Department of Energy. The RELAP-7 code is a fully implicit code and the preconditioned Jacobian-free Newton-Krylov (JFNK) method is used to solve the discretized nonlinear system. This paper presents a set of analytical models for simulating the flow through the Terry turbine nozzles when inlet fluid is pure steam. The implementation of the models into RELAP-7 will be briefly discussed. In the Sandia model, the turbine bucket inlet velocity is provided according to a reduced-order model, which was obtained from a large number of CFD simulations. In this work, we propose an alternative method, using an under-expanded jet model to obtain the velocity and thermodynamic conditions for the turbine bucket inlet. The models include both adiabatic expansion process inside the nozzle and free expansion process out of the nozzle to reach the ambient pressure. The combined models are able to predict the steam mass flow rate and supersonic velocity to the Terry turbine bucket entrance, which are the necessary input conditions for the Terry Turbine rotor model. The nozzle analytical models were validated with experimental data and

  11. Analysis of the combined effect of hydrogrinding process and inclination angle on hydraulic performance of diesel injection nozzles

    International Nuclear Information System (INIS)

    Salvador, F.J.; Carreres, M.; Jaramillo, D.; Martínez-López, J.

    2015-01-01

    Highlights: • Effect of inclination angle and rounding radius of diesel nozzle holes is explored. • The study starts with experimental tests and is extended by CFD simulations. • A CFD code with a HEM model for two-phase flow and a RANS approach is used. • Differences in flow parameters, cavitation inception and morphology are analysed. • The flow is generally favoured by low inclination angles and high rounding radius. - Abstract: A computational study to investigate the influence of the orifices inclination and the rounding radius at the orifice inlet (consequence of the hydro-erosive grinding process applied after the orifices machining) over the internal nozzle flow is performed in this paper. The study starts with the analysis of experimental results where the mass flow and momentum flux of two nozzles with very different values of these two variables are compared. This analysis shows relatively small differences in terms of mass flow and momentum flux, since the higher losses associated to the higher deflection of the streamlines with a higher inclination of the orifices are counteracted by the higher rounding radius, which favours the flow entrance to the orifice. To explain this experimental outcome, an extensive computational study involving nine geometries that combine different inclination angles and rounding radius is conducted, in order to quantify the influence of both parameters on the flow separately, as well as to assess the potential of their combination. These geometries are compared in terms of discharge coefficient, critical cavitation conditions and effective injection velocity, among others. Results show differences up to 15% in terms of mass flow rate and 8% for the effective injection velocity among the two extreme cases (lowest inclination and highest hydro-erosion level versus the nozzle with the highest inclination and lowest hydro-erosion level). Given the importance of these phenomena on the subsequent mixing and combustion

  12. Internal variability of fine-scale components of meteorological fields in extended-range limited-area model simulations with atmospheric and surface nudging

    Science.gov (United States)

    Separovic, Leo; Husain, Syed Zahid; Yu, Wei

    2015-09-01

    Internal variability (IV) in dynamical downscaling with limited-area models (LAMs) represents a source of error inherent to the downscaled fields, which originates from the sensitive dependence of the models to arbitrarily small modifications. If IV is large it may impose the need for probabilistic verification of the downscaled information. Atmospheric spectral nudging (ASN) can reduce IV in LAMs as it constrains the large-scale components of LAM fields in the interior of the computational domain and thus prevents any considerable penetration of sensitively dependent deviations into the range of large scales. Using initial condition ensembles, the present study quantifies the impact of ASN on IV in LAM simulations in the range of fine scales that are not controlled by spectral nudging. Four simulation configurations that all include strong ASN but differ in the nudging settings are considered. In the fifth configuration, grid nudging of land surface variables toward high-resolution surface analyses is applied. The results show that the IV at scales larger than 300 km can be suppressed by selecting an appropriate ASN setup. At scales between 300 and 30 km, however, in all configurations, the hourly near-surface temperature, humidity, and winds are only partly reproducible. Nudging the land surface variables is found to have the potential to significantly reduce IV, particularly for fine-scale temperature and humidity. On the other hand, hourly precipitation accumulations at these scales are generally irreproducible in all configurations, and probabilistic approach to downscaling is therefore recommended.

  13. Beyond imperviousness: A statistical approach to identifying functional differences between development morphologies on variable source area-type response in urbanized watersheds

    Science.gov (United States)

    Lim, T. C.

    2016-12-01

    Empirical evidence has shown linkages between urbanization, hydrological regime change, and degradation of water quality and aquatic habitat. Percent imperviousness, has long been suggested as the dominant source of these negative changes. However, recent research identifying alternative pathways of runoff production at the watershed scale have called into question percent impervious surface area's primacy in urban runoff production compared to other aspects of urbanization including change in vegetative cover, imported water and water leakages, and the presence of drainage infrastructure. In this research I show how a robust statistical methodology can detect evidence of variable source area (VSA)-type hydrologic response associated with incremental hydraulic connectivity in watersheds. I then use logistic regression to explore how evidence of VSA-type response relates to the physical and meterological characteristics of the watershed. I find that impervious surface area is highly correlated with development, but does not add significant explanatory power beyond percent developed in predicting VSA-type response. Other aspects of development morphology, including percent developed open space and type of drainage infrastructure also do not add to the explanatory power of undeveloped land in predicting VSA-type response. Within only developed areas, the effect of developed open space was found to be more similar to that of total impervious area than to undeveloped land. These findings were consistent when tested across a national cross-section of urbanized watersheds, a higher resolution dataset of Baltimore Metropolitan Area watersheds, and a subsample of watersheds confirmed not to be served by combined sewer systems. These findings suggest that land development policies that focus on lot coverage should be revisited, and more focus should be placed on preserving native vegetation and soil conditions alongside development.

  14. Evaluation of the U.S. Geological Survey Landsat burned area essential climate variable across the conterminous U.S. using commercial high-resolution imagery

    Science.gov (United States)

    Vanderhoof, Melanie; Brunner, Nicole M.; Beal, Yen-Ju G.; Hawbaker, Todd J.

    2017-01-01

    The U.S. Geological Survey has produced the Landsat Burned Area Essential Climate Variable (BAECV) product for the conterminous United States (CONUS), which provides wall-to-wall annual maps of burned area at 30 m resolution (1984–2015). Validation is a critical component in the generation of such remotely sensed products. Previous efforts to validate the BAECV relied on a reference dataset derived from Landsat, which was effective in evaluating the product across its timespan but did not allow for consideration of inaccuracies imposed by the Landsat sensor itself. In this effort, the BAECV was validated using 286 high-resolution images, collected from GeoEye-1, QuickBird-2, Worldview-2 and RapidEye satellites. A disproportionate sampling strategy was utilized to ensure enough burned area pixels were collected. Errors of omission and commission for burned area averaged 22 ± 4% and 48 ± 3%, respectively, across CONUS. Errors were lowest across the western U.S. The elevated error of commission relative to omission was largely driven by patterns in the Great Plains which saw low errors of omission (13 ± 13%) but high errors of commission (70 ± 5%) and potentially a region-growing function included in the BAECV algorithm. While the BAECV reliably detected agricultural fires in the Great Plains, it frequently mapped tilled areas or areas with low vegetation as burned. Landscape metrics were calculated for individual fire events to assess the influence of image resolution (2 m, 30 m and 500 m) on mapping fire heterogeneity. As the spatial detail of imagery increased, fire events were mapped in a patchier manner with greater patch and edge densities, and shape complexity, which can influence estimates of total greenhouse gas emissions and rates of vegetation recovery. The increasing number of satellites collecting high-resolution imagery and rapid improvements in the frequency with which imagery is being collected means greater opportunities to utilize these sources

  15. Dual Nozzle Aerodynamic and Cooling Analysis Study.

    Science.gov (United States)

    1981-02-27

    SSTO ) and Heavy Lift Launch Vehicle (HLLV), may embrace such capabili- ties as dual-mode operation and in-flight changes in area ratio for altitude...engines with resultant advantages. The baseline engine application, analzyed in this and earlier studies, is a tripropellant single-stage-to-orbit ( SSTO ...potential 8 1, Introduction (cont.) power cycles and generate parametric data for a tripropellant SSTO vehicle engine. A preliminary performance prediction

  16. Leaf area index estimation in a pine plantation with LAI-2000 under direct sunlight conditions: relationship with inventory and hydrologic variables

    International Nuclear Information System (INIS)

    Molina, A.; Campo, A. D. del

    2011-01-01

    LAI is a key factor in light and rainfall interception processes in forest stands and, for this reason, is called to play an important role in global change adaptive silviculture. Therefore, it is necessary to develop practical and operative methodologies to measure this parameter as well as simple relationships with other silviculture variables. This work has studied 1) the feasibility of LAI-2000 sensor in estimating LAI-stand when readings are taken under direct sunlight conditions; and 2) the ability of LAI in studying rainfall partitioned into throughfall (T) in an Aleppo pine stand after different thinning intensities, as well as its relationships to basal area, (G), cover (FCC), and tree density (D). Results showed that the angular correction scheme applied to LAI-2000 direct-sunlight readings stabilized them for different solar angles, allowing a better operational use of LAI-2000 in Mediterranean areas, where uniform overcast conditions are difficult to meet and predict. Forest cover showed the highest predictive ability of LAI (R 2 = 0.98; S = 0.28), then G (R 2 = 0.96; S = 0.43) and D (R 2 = 0.50; S = 0.28). In the hydrological plane, T increased with thinning intensity, being G the most explanatory variable (R 2 = 0.81; S = 3.07) and LAI the one that showed the poorest relation with it (R 2 = 0.69; S = 3.95). These results open a way for forest hydrologic modeling taking LAI as an input variable either estimated form LAI-2000 or deducted from inventory data. (Author) 36 refs.

  17. Apparatus and method for a gas turbine nozzle

    Science.gov (United States)

    Zuo, Baifang; Ziminsky, Willy Steve; Johnson, Thomas Edward; Intile, John Charles; Lacy, Benjamin Paul

    2013-02-05

    A nozzle includes an inlet, an outlet, and an axial centerline. A shroud surrounding the axial centerline extends from the inlet to the outlet and defines a circumference. The circumference proximate the inlet is greater than the circumference at a first point downstream of the inlet, and the circumference at the first point downstream of the inlet is less than the circumference at a second point downstream of the first point. A method for supplying a fuel through a nozzle directs a first airflow along a first path and a second airflow along a second path separate from the first path. The method further includes injecting the fuel into at least one of the first path or the second path and accelerating at least one of the first airflow or the second airflow.

  18. Three-Dimensional Flow Behavior Inside the Submerged Entry Nozzle

    Science.gov (United States)

    Real-Ramirez, Cesar Augusto; Carvajal-Mariscal, Ignacio; Sanchez-Silva, Florencio; Cervantes-de-la-Torre, Francisco; Diaz-Montes, Jesus; Gonzalez-Trejo, Jesus

    2018-05-01

    According to various authors, the surface quality of steel depends on the dynamic conditions that occur within the continuous casting mold's upper region. The meniscus, found in that upper region, is where the solidification process begins. The liquid steel is distributed into the mold through a submerged entry nozzle (SEN). In this paper, the dynamic behavior inside the SEN is analyzed by means of physical experiments and numerical simulations. The particle imaging velocimetry technique was used to obtain the vector field in different planes and three-dimensional flow patterns inside the SEN volume. Moreover, large eddy simulation was performed, and the turbulence model results were used to understand the nonlinear flow pattern inside the SEN. Using scaled physical and numerical models, quasi-periodic behavior was observed due to the interaction of two three-dimensional vortices that move inside the SEN lower region located between the exit ports of the nozzle.

  19. Analysis of cracked pressure vessel nozzles by finite elements

    International Nuclear Information System (INIS)

    Reynen, J.

    1975-01-01

    In order to assess the safety of pressure vessel nozzles, the analysis should take into account cracks. The paper describes various algorithms, their computer implementations and relative merits to define in an effective way strain energy release rates along the tip front of arbitrary 3 D cracks under arbitary load including thermal strains. These techniques are basically equivalent to substructuring techniques and consequently they can be implemented to only FEM program able to deal with the data handling problems of the substructuring technique. Examples are given carried out with a substructure version of the BERSAFE system. These examples include a corner crack in a pressure vessel nozzle loaded by internal pressure and by thermal stresses. (Auth.)

  20. Hypersonic nozzle/afterbody CFD code validation. I - Experimental measurements

    Science.gov (United States)

    Spaid, Frank W.; Keener, Earl R.

    1993-01-01

    This study was conducted to obtain a detailed experimental description of the flow field created by the interaction of a single-expansion-ramp-nozzle flow with a hypersonic external stream. Data were obtained from a generic nozzle/afterbody model in the 3.5-Foot Hypersonic Wind Tunnel of the NASA Ames Research Center in a cooperative experimental program involving Ames and the McDonnell Douglas Research Laboratories. This paper presents experimental results consisting primarily of surveys obtained with a five-hole total-pressure/flow-direction probe and a total-temperature probe. These surveys were obtained in the flow field created by the interaction between the underexpanded jet plume and the external flow.

  1. Bundled multi-tube nozzle for a turbomachine

    Science.gov (United States)

    Lacy, Benjamin Paul; Ziminsky, Willy Steve; Johnson, Thomas Edward; Zuo, Baifang; York, William David; Uhm, Jong Ho

    2015-09-22

    A turbomachine includes a compressor, a combustor operatively connected to the compressor, an end cover mounted to the combustor, and an injection nozzle assembly operatively connected to the combustor. The injection nozzle assembly includes a cap member having a first surface that extends to a second surface. The cap member further includes a plurality of openings. A plurality of bundled mini-tube assemblies are detachably mounted in the plurality of openings in the cap member. Each of the plurality of bundled mini-tube assemblies includes a main body section having a first end section and a second end section. A fluid plenum is arranged within the main body section. A plurality of tubes extend between the first and second end sections. Each of the plurality of tubes is fluidly connected to the fluid plenum.

  2. Investigation of nozzle contours in the CSIR supersonic wind tunnel

    CSIR Research Space (South Africa)

    Vallabh, Bhavya

    2017-09-01

    Full Text Available Contours in the CSIR Supersonic Wind Tunnel B Vallabha,b and BW Skewsa Received 17 February 2017, in revised form 23 June 2017 and accepted 25 June 2017 R & D Journal of the South African Institution of Mechanical Engineering 2017, 33, 32-41 http... with the Sivells’ nozzle design method and the method of characteristics technique to design the nozzle profiles for the full supersonic Mach number range 𝟏𝟏 ≀ 𝑎𝑎 ≀ 𝟒𝟒.5 of the facility. Automatic computation was used for the profile...

  3. Variable volume combustor with a conical liner support

    Science.gov (United States)

    Johnson, Thomas Edward; McConnaughhay, Johnie Franklin; Keener, Chrisophter Paul; Ostebee, Heath Michael

    2017-06-27

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a conical liner support supporting the liner.

  4. Design and Calibration of a Transformer Controlled Variable ...

    African Journals Online (AJOL)

    A new approach for the design and construction of a variable rainfall simulator using an auto transformer which is aimed at soil erosion research was explored. The method involves using a water pump, a variable voltage regulator and a set of nozzles for the simulation of rainfall. It was found that the variation of rainfall ...

  5. Scalable Fabrication of Supercapacitors by Nozzle-free Electrospinning

    OpenAIRE

    Shi, Kaiyuan; Giapis, Konstantinos P.

    2018-01-01

    Nozzle-free electrospinning was investigated as a facile technique for producing nanoscale materials for supercapacitors. MnO2 nanofibers and their composites with multiwalled carbon nanotubes (MWCNTs) were synthesized in a single step, using polyvinylpyrrolidone (PVP) and Mn(CH_3COO)_2·4H_2O as starting materials, followed up by heat treatment in ambient air. Nanofibers of relatively uniform diameter were produced at high rates. The nanofibers exhibited good electrical contact between MnO_2 ...

  6. Effective hydraulic resistance of actuator nozzle generating a periodic jet

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav

    2012-01-01

    Roč. 179, JUN 2012 (2012), s. 211-222 ISSN 0924-4247 R&D Projects: GA ČR(CZ) GCP101/11/J019; GA TA ČR(CZ) TA02020795 Institutional research plan: CEZ:AV0Z20760514 Keywords : nozzle * periodic flow * compressibility Subject RIV: BK - Fluid Dynamics Impact factor: 1.841, year: 2012 http://www.sciencedirect.com/science/article/pii/S0924424712001781

  7. Characterization of Rotating Detonation Engine Exhaust Through Nozzle Guide Vanes

    Science.gov (United States)

    2013-03-21

    ENY/13-M09 Abstract A Rotating Detonation Engine ( RDE ) has higher thermal efficiencies in comparison to its traditional gas turbine counterparts. Thus...as budgets decrease and fuel costs increase, RDEs have become a research focus for the United States Air Force. An integration assembly for attaching...the first Nozzle Guide Vane (NGV) section from a T63 gas turbine engine to a 6 inch diameter RDE was designed and built for this study. Pressure

  8. Magnetic Nozzles for Plasma Thrusters: Acceleration, Thrust, and Detachment Mechanisms

    Science.gov (United States)

    2011-10-01

    neutral double layer. A very detailed study of this surface discontinuity has been culminated [4]. It had been claimed that the presence of this DL could...field assures that electrons are strongly-magnetized whereas ions are partially-magnetized. The use of the method of characteristic surfaces (i.e...z = const disk. (d) Ambipolar electric field and equipotential lines for plasmas with a 0.2 fraction of 9-times hotter electrons at the nozzle

  9. Device to enrich uranium using the separation nozzle method

    International Nuclear Information System (INIS)

    Wenzel, W.

    1984-01-01

    Separation nozzle units, coolers and the radial-flow compressor are integrated in such manner that the volume of the device is reduced and the efficiency is increased. The radial-flow compressor that is placed in a central and axial position in the cylindrical casing of the tank is concentrically surrounded by the other elements, which are arranged in a way that regular maintenance becomes possible without difficulties. The detailed description is supplemented by drawings. (ori./PW)

  10. Three Dimensional Steady Subsonic Euler Flows in Bounded Nozzles

    OpenAIRE

    Chen, Chao; Xie, Chunjing

    2013-01-01

    In this paper, we study the existence and uniqueness of three dimensional steady Euler flows in rectangular nozzles when prescribing normal component of momentum at both the entrance and exit. If, in addition, the normal component of the voriticity and the variation of Bernoulli's function at the exit are both zero, then there exists a unique subsonic potential flow when the magnitude of the normal component of the momentum is less than a critical number. As the magnitude of the normal compon...

  11. Indoor spray measurement of spray drift potential using a spray drift test bench : effect of drift-reducing nozzle types, spray boom height, nozzle spacing and forward speed

    NARCIS (Netherlands)

    Moreno Ruiz, J.R.

    2014-01-01

    In a series of indoor experiments spray drift potential was assessed when spraying over a spray drift testbench with two different driving speeds, 2m/s and 4m/s, two different spray boom heights, 30 cm and 50 cm, and two different nozzle spacing, 25 cm and 50 cm, for six different nozzle types. The

  12. CFD Models of a Serpentine Inlet, Fan, and Nozzle

    Science.gov (United States)

    Chima, R. V.; Arend, D. J.; Castner, R. S.; Slater, J. W.; Truax, P. P.

    2010-01-01

    Several computational fluid dynamics (CFD) codes were used to analyze the Versatile Integrated Inlet Propulsion Aerodynamics Rig (VIIPAR) located at NASA Glenn Research Center. The rig consists of a serpentine inlet, a rake assembly, inlet guide vanes, a 12-in. diameter tip-turbine driven fan stage, exit rakes or probes, and an exhaust nozzle with a translating centerbody. The analyses were done to develop computational capabilities for modeling inlet/fan interaction and to help interpret experimental data. Three-dimensional Reynolds averaged Navier-Stokes (RANS) calculations of the fan stage were used to predict the operating line of the stage, the effects of leakage from the turbine stream, and the effects of inlet guide vane (IGV) setting angle. Coupled axisymmetric calculations of a bellmouth, fan, and nozzle were used to develop techniques for coupling codes together and to investigate possible effects of the nozzle on the fan. RANS calculations of the serpentine inlet were coupled to Euler calculations of the fan to investigate the complete inlet/fan system. Computed wall static pressures along the inlet centerline agreed reasonably well with experimental data but computed total pressures at the aerodynamic interface plane (AIP) showed significant differences from the data. Inlet distortion was shown to reduce the fan corrected flow and pressure ratio, and was not completely eliminated by passage through the fan

  13. Chemical processes in the turbine and exhaust nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Lukachko, S P; Waitz, I A [Massachusetts Inst. of Tech., Cambridge, MA (United States). Aero-Environmental Lab.; Miake-Lye, R C; Brown, R C; Anderson, M R [Aerodyne Research, Inc., Billerica, MA (United States); Dawes, W N [University Engineering Dept., Cambridge (United Kingdom). Whittle Lab.

    1998-12-31

    The objective is to establish an understanding of primary pollutant, trace species, and aerosol chemical evolution as engine exhaust travels through the nonuniform, unsteady flow fields of the turbine and exhaust nozzle. An understanding of such processes is necessary to provide accurate inputs for plume-wake modeling efforts and is therefore a critical element in an assessment of the atmospheric effects of both current and future aircraft. To perform these studies, a numerical tool was developed combining the calculation of chemical kinetics and one-, two-, or three-dimensional (1-D, 2-D, 3-D) Reynolds-averaged flow equations. Using a chemistry model that includes HO{sub x}, NO{sub y}, SO{sub x}, and CO{sub x} reactions, several 1-D parametric analyses were conducted for the entire turbine and exhaust nozzle flow path of a typical advanced subsonic engine to understand the effects of various flow and chemistry uncertainties on a baseline 1-D result. These calculations were also used to determine parametric criteria for judging 1-D, 2-D, and 3-D modeling requirements as well as to provide information about chemical speciation at the nozzle exit plane. (author) 9 refs.

  14. Nozzle Flow with Vibrational Nonequilibrium. Ph.D. Thesis

    Science.gov (United States)

    Landry, John Gary

    1995-01-01

    Flow of nitrogen gas through a converging-diverging nozzle is simulated. The flow is modeled using the Navier-Stokes equations that have been modified for vibrational nonequilibrium. The energy equation is replaced by two equations. One equation accounts for energy effects due to the translational and rotational degrees of freedom, and the other accounts for the affects due to the vibrational degree of freedom. The energy equations are coupled by a relaxation time which measures the time required for the vibrational energy component to equilibrate with the translational and rotational energy components. An improved relaxation time is used in this thesis. The equations are solved numerically using the Steger-Warming flux vector splitting method and the Implicit MacCormack method. The results show that uniform flow is produced outside of the boundary layer. Nonequilibrium exists in both the converging and diverging nozzle sections. The boundary layer region is characterized by a marked increase in translational-rotational temperature. The vibrational temperature remains frozen downstream of the nozzle, except in the boundary layer.

  15. Inspections of CRDM Nozzle Penetrations in Paks NPP

    International Nuclear Information System (INIS)

    Doszpod, B.; Doczi, M.

    2008-01-01

    During the maintenance outage of Unit 2 of Paks Nuclear Power Plant in 2002, performing the regular drop-test of Control Rod Driving Mechanisms (CRDM) reduced drop-speed was observed in case of one CRDM. In spite of the measured value of speed was inside the acceptance limit, so it was still satisfactory, decision was made to disassemble the CRDM to clarify the cause of the speed-anomaly. After removal of the CRDM, by means of visual inspection deformation (bulge) was observed on the inside surface of the heat protection tube of the CRDM nozzle penetration. Deformation was big enough to obstruct the free movement of CRDM. After the deformed heat protection tube was removed, significant bulge was observed also on the corrosion protection tube, at the same elevation. As the root cause of these deformations, presence of water in the space between the CRDM nozzle and the corrosion protection tube was assumed. Non destructive inspection procedures were worked out and utilized to detect the presence of water in the space in question and to find the possible way of water inlet. Performed inspections successfully localized the place of water inlet. Developed inspection program of CRDM nozzles has to be performed during each outage on each unit. Paper deals with introduction of the phenomenon, the cause of damage, inspection the procedures which were worked out and applied, summarize the results of inspections performed.(author)

  16. Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

    Science.gov (United States)

    Fritz, Bradley K.; Hoffmann, W. Clint

    2016-01-01

    When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected. PMID:27684589

  17. Cracking at nozzle corners in the nuclear pressure vessel industry

    International Nuclear Information System (INIS)

    Smith, C.W.

    1986-01-01

    Cracks in nozzle corners at the pressure boundary of nuclear reactors have been frequently observed in service. These cracks tend to form with radial orientations with respect to the nozzle central axis and are believed to be initiated by thermal shock. However, their growth is believed to be primarily due to a steady plus a fluctuating internal pressure. Due to the impracticality of fracture testing of full-scale models, the Oak Ridge National Laboratory instituted the use of an intermediate test vessel (ITV) for use in fracture testing which had the same wall thickness and nozzle size as the prototype but significantly reduced overall length and diameter. In order to determine whether or not these ITVs could provide realistic data for full-scale reactor vessels, laboratory models of full-scale boiling water reactors and ITVs were constructed and tested. After briefly reviewing the laboratory testing and correlating results with service experience, results obtained will be used to draw some general conclusions regarding the stable growth of nonplanar cracks with curved crack fronts which are the most common precursors to fracture of pressure vessel components near junctures. Use of linear elastic fracture mechanics is made in determining stress-intensity distribution along the crack fronts

  18. Chemical processes in the turbine and exhaust nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Lukachko, S.P.; Waitz, I.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Aero-Environmental Lab.; Miake-Lye, R.C.; Brown, R.C.; Anderson, M.R. [Aerodyne Research, Inc., Billerica, MA (United States); Dawes, W.N. [University Engineering Dept., Cambridge (United Kingdom). Whittle Lab.

    1997-12-31

    The objective is to establish an understanding of primary pollutant, trace species, and aerosol chemical evolution as engine exhaust travels through the nonuniform, unsteady flow fields of the turbine and exhaust nozzle. An understanding of such processes is necessary to provide accurate inputs for plume-wake modeling efforts and is therefore a critical element in an assessment of the atmospheric effects of both current and future aircraft. To perform these studies, a numerical tool was developed combining the calculation of chemical kinetics and one-, two-, or three-dimensional (1-D, 2-D, 3-D) Reynolds-averaged flow equations. Using a chemistry model that includes HO{sub x}, NO{sub y}, SO{sub x}, and CO{sub x} reactions, several 1-D parametric analyses were conducted for the entire turbine and exhaust nozzle flow path of a typical advanced subsonic engine to understand the effects of various flow and chemistry uncertainties on a baseline 1-D result. These calculations were also used to determine parametric criteria for judging 1-D, 2-D, and 3-D modeling requirements as well as to provide information about chemical speciation at the nozzle exit plane. (author) 9 refs.

  19. Thermal Analysis of the Fastrac Chamber/Nozzle

    Science.gov (United States)

    Davis, Darrell

    2001-01-01

    This paper will describe the thermal analysis techniques used to predict temperatures in the film-cooled ablative rocket nozzle used on the Fastrac 60K rocket engine. A model was developed that predicts char and pyrolysis depths, liner thermal gradients, and temperatures of the bondline between the overwrap and liner. Correlation of the model was accomplished by thermal analog tests performed at Southern Research, and specially instrumented hot fire tests at the Marshall Space Flight Center. Infrared thermography was instrumental in defining nozzle hot wall surface temperatures. In-depth and outboard thermocouple data was used to correlate the kinetic decomposition routine used to predict char and pyrolysis depths. These depths were anchored with measured char and pyrolysis depths from cross-sectioned hot-fire nozzles. For the X-34 flight analysis, the model includes the ablative Thermal Protection System (TPS) material that protects the overwrap from the recirculating plume. Results from model correlation, hot-fire testing, and flight predictions will be discussed.

  20. Thermal Analysis of the MC-1 Chamber/Nozzle

    Science.gov (United States)

    Davis, Darrell W.; Phelps, Lisa H. (Technical Monitor)

    2001-01-01

    This paper will describe the thermal analysis techniques used to predict temperatures in the film-cooled ablative rocket nozzle used on the MC-1 60K rocket engine. A model was developed that predicts char and pyrolysis depths, liner thermal gradients, and temperatures of the bondline between the overwrap and liner. Correlation of the model was accomplished by thermal analog tests performed at Southern Research, and specially instrumented hot fire tests at the Marshall Space Flight Center. Infrared thermography was instrumental in defining nozzle hot wall surface temperatures. In-depth and outboard thermocouple data was used to correlate the kinetic decomposition routine used to predict char and pyrolysis depths. These depths were anchored with measured char and pyrolysis depths from cross-sectioned hot-fire nozzles. For the X-34 flight analysis, the model includes the ablative Thermal Protection System (TPS) material that protects the overwrap from the recirculating plume. Results from model correlation, hot-fire testing, and flight predictions will be discussed.

  1. Interannual variability of a precipitation gradient along the semi-arid catchment areas for the metropolitan region of Lima- Peru in relation to atmospheric circulation at the mesoscale

    Science.gov (United States)

    Otto, Marco; Seidel, Jochen; Trachte, Katja

    2013-04-01

    The main moisture source for precipitation on the western slopes of the Central Andes is located east of the mountain range known as the Amazon basin. However, the Andean mountains, which reach up to 6000 m a.s.l., strongly influence climatic conditions along the Pacific coastline of South America as a climatic barrier for the low-level tropospheric flow and associated moisture transport from the Amazon basin. Additional, large scale subsidence caused by the South Pacific High inhabits convective rainfall at the Pacific coast where large metropolitan areas such as the Peruvian capital Lima are located. Two contrasts in precipitation can be found while crossing the Andean mountains from West to East. On the Pacific coast, at the location of the metropolitan area of Lima, no more than 10 mm mean annual rainfall occurs. In contrast, up to 1000 mm mean annual rainfall occur only 100 km east of Lima within the upper region (4000 m .a.s.l.) of the Western Cordillera. The transition takes place along the western slopes of the Western Cordillera and is characterised by a strong precipitation gradient. Here, catchment areas are located that provide most of the water resources needed to sustain an urban area of approximately 10 million people. This study investigates the interannual variability of the precipitation gradient between 1998 and 2012. The analysis is based on daily precipitation data of 22 rain gauge station, daily rainfall data of the Tropical Rainfall Mission (TRMM 3B42) at 0.25 degrees and reanalysis data at 36 km spatial resolution at the mesoscale. The reanalysis data was produced using the Weather Research and Forecasting Model. Station data was provided by the Peruvian weather service during the project "Sustainable Water and Wastewater Management in Urban Growth Centres Coping with Climate Change - Concepts for Lima Metropolitana (Peru) (LiWa)", which is financed by the German Federal Ministry of Education and Research (BMBF). We are interested in the

  2. Influence of throttling of the heavy fraction on the uranium isotope separation in the separation nozzle

    International Nuclear Information System (INIS)

    Bley, P.; Ehrfeld, W.; Heiden, U.

    1978-04-01

    In a separation nozzle cascade for enrichment of U-235 the cut of the separation elements is adjusted by throttling the heavy fraction. This control process influences directly the flow properties in the nozzle and may noticeably change its separation characteristics. This paper deals with an experimental investigation of the throttling effect on the separation and control characteristics of the separation nozzle operated with a H 2 /UF 6 mixture. In consideration of the extremely small characteristic dimensions of commercial separation nozzle elements the influence of manufacturing tolerances on the characteristics of the throttled nozzle was analysed in detail. It appears, that the elementary effect of isotope separation increases by throttling of the heavy fraction up to 5% without changing the optimum operating conditions. This increase of the elementary effect is not only obtained for separation nozzles with zero tolerances but also for separation nozzles having finite tolerances of the skimmer position. Tolerances of the nozzle width, however, become increasingly detrimental, when the heavy fraction is throttled. Regarding the control characteristics of the separation nozzle it was found out, that the UF 6 -cut of the throttled nozzle reacts more sensitively to alterations of the operating pressures and less sensitively to alterations of the UF 6 -concentration of the process gas mixture. (orig.) [de

  3. Thrust Augmentation by Airframe-Integrated Linear-Spike Nozzle Concept for High-Speed Aircraft

    Directory of Open Access Journals (Sweden)

    Hidemi Takahashi

    2018-02-01

    Full Text Available The airframe-integrated linear-spike nozzle concept applied to an external nozzle for high-speed aircraft was evaluated with regard to the thrust augmentation capability and the trim balance. The main focus was on the vehicle aftbody. The baseline airframe geometry was first premised to be a hypersonic waverider design. The baseline aftbody case had an external nozzle comprised of a simple divergent nozzle and was hypothetically replaced with linear-spike external nozzle configurations. Performance evaluation was mainly conducted by considering the nozzle thrust generated by the pressure distribution on the external nozzle surface at the aftbody portion calculated by computer simulation at a given cruise condition with zero angle of attack. The thrust performance showed that the proposed linear-spike external nozzle concept was beneficial in thrust enhancement compared to the baseline geometry because the design of the proposed concept had a compression wall for the exhaust flow, which resulted in increasing the wall pressure. The configuration with the boattail and the angled inner nozzle exhibited further improvement in thrust performance. The trim balance evaluation showed that the aerodynamic center location appeared as acceptable. Thus, benefits were obtained by employing the airframe-integrated linear-spike external nozzle concept.

  4. An analysis of the shielding gas flow from a coaxial conical nozzle during high power CO2 laser welding

    International Nuclear Information System (INIS)

    Ancona, Antonio; Sibillano, Teresa; Lugara, Pietro Mario; Gonnella, Giuseppe; Pascazio, Giuseppe; Maffione, Donato

    2006-01-01

    An experimental and theoretical study on the role of the nitrogen gas stream, exiting from a conventional conical nozzle tip during a laser welding process, has been carried out. A mathematical model has been used, based on the Navier-Stokes equations which express fundamental conservation laws of mass, momentum and energy for a compressible fluid. Numerical simulations of the gas stream colliding onto a plane surface have been performed showing the effects of variations of inlet gas pressure, nozzle exit diameter and standoff distance on the density and Mach number contours, axis pressure of the gas jet and plate pressure produced on the workpiece surface. Laser welding experiments have been performed on carbon and stainless steel specimens, by varying the process parameters in the same range as in the simulations and keeping constant the incident power and the travel speed. Two different gas stream regimes were found, namely sonic and subsonic, which were experimentally verified to produce cutting and welding conditions, respectively. Weld performances have been evaluated in terms of bead width, penetration depth and melted area. Nozzle standoff distance was found to have a negligible influence, while the exit diameter and the flow rate significantly affect the weld results. The numerical predictions allowed an explanation of the experimental results yielding useful suggestions for enhancing the weld quality, acting simply on the shielding gas parameters

  5. Silicon micro venturi nozzles for cost-efficient spray coating of thin organic P3HT/PCBM layers

    Science.gov (United States)

    Betz, Michael A.; Büchele, Patric; Brünnler, Manfred; Deml, Sonja; Lechner, Alfred

    2017-01-01

    Improvements on spray coating are of particular interest to different fields of technology as it is a scalable deposition method and processing from solutions offer various application possibilities outside of typical facilities. When it comes to the deposition of expensive and film-forming media such as organic semiconductors, consumption and nozzle cleaning issues are of particular importance. We demonstrate the simple steps to design and fabricate micro venturi nozzles for economical spray coating with a consumption as low as 30-50 µl · min-1. For spray coating an active area of 25 cm2 a 2.45-4.01 fold coating efficiency is observed compared to a conventional airbrush nozzle set. The electrical characterization of first diodes sprayed with an active layer thickness of ~750 nm using a single micronozzle at a coating speed of 1.7 cm2 · min-1 reveals a good external quantum efficiency of 72.9% at 532 nm and a dark current of ~7.4 · 10-5 mA · cm-2, both measured at  -2 V. Furthermore, the high resistance of the micronozzles against solvents and most acids is provided through realization in a silicon wafer with silicon dioxide encapsulation, therefore allowing easy and effective cleaning.

  6. Silicon micro venturi nozzles for cost-efficient spray coating of thin organic P3HT/PCBM layers

    International Nuclear Information System (INIS)

    Betz, Michael A; Brünnler, Manfred; Deml, Sonja; Lechner, Alfred; Büchele, Patric

    2017-01-01

    Improvements on spray coating are of particular interest to different fields of technology as it is a scalable deposition method and processing from solutions offer various application possibilities outside of typical facilities. When it comes to the deposition of expensive and film-forming media such as organic semiconductors, consumption and nozzle cleaning issues are of particular importance. We demonstrate the simple steps to design and fabricate micro venturi nozzles for economical spray coating with a consumption as low as 30–50 µ l · min −1 . For spray coating an active area of 25 cm 2 a 2.45–4.01 fold coating efficiency is observed compared to a conventional airbrush nozzle set. The electrical characterization of first diodes sprayed with an active layer thickness of ∼750 nm using a single micronozzle at a coating speed of 1.7 cm 2 · min −1 reveals a good external quantum efficiency of 72.9% at 532 nm and a dark current of ∼7.4 · 10 −5 mA · cm −2 , both measured at  −2 V. Furthermore, the high resistance of the micronozzles against solvents and most acids is provided through realization in a silicon wafer with silicon dioxide encapsulation, therefore allowing easy and effective cleaning. (paper)

  7. Estimation of inelastic behavior for a tapered nozzle in vessel due to thermal transient load using stress redistribution locus method

    International Nuclear Information System (INIS)

    Kobayashi, Ken-ichi; Yamada, Jun-ichi

    2010-01-01

    Simplified inelastic design procedures for elevated temperature components have been required to reduce simulation cost and to shorten a period of time for developing new projects. Stress redistribution locus (SRL) method has been proposed to provide a reasonable estimate employing both the elastic FEM analysis and a unique hyperbolic curve: ε tilde={1/σ tilde + (κ - 1)σ tilde}/κ, where ε tilde and σ tilde show dimensionless strain and stress normalized by corresponding elastic ones, respectively. This method is based on a fact that stress distribution in well deformed or high temperature components would change with deformation or time, and that the relation between the dimensionless stress and strain traces a kind of the elastic follow-up locus in spite of the constitutive equation of material and loading modes. In this paper, FEM analyses incorporating plasticity and creep in were performed for a tapered nozzle in reactor vessel under some thermal transient loads through the nozzle thickness. The normalized stress and strain was compared with the proposed SRL curve. Calculation results revealed that a critical point in the tapered nozzle due to the thermal transient load depended on a descending rate of temperature from the higher temperature in the operation cycle. Since the inelastic behavior in the nozzle resulted in a restricted area, the relationship between the normalized stress and strain was depicted inside the proposed SRL curve: Coefficient κ of the SRL in analyses is greater than the proposed one, and the present criterion guarantees robust structures for complicated components involving inelastic deformation. (author)

  8. The effect of coarse-droplet spraying with double flat fan air induction nozzle and spray volume adjustment model on the efficiency of fungicides and residues in processing tomato

    Directory of Open Access Journals (Sweden)

    Henryk Ratajkiewicz

    2018-04-01

    Full Text Available The study was conducted for the purpose of improving the application of fungicides against potato late blight (Phytophthora infestans (Mont. de Bary (PLB in processing tomato. The usability of coarse spray quality with double flat fan air induction IDKT12003 nozzle and the impact of fixed and variable spray volume and adjuvants during alternate application of azoxystrobin and chlorothalonil were analysed on the basis of plant infestation and fungicide residues. The variable spray volume was calculated based on the number of leaves on a plant. The study was conducted during three vegetation seasons. Spraying of plants with significantly flattened canopies during the peak of the fructification season using an IDKT12003 nozzle was as effective as in the case of fine spraying performed with an XR11003 nozzle and facilitated the increase of fungicides residue. In the case of plants with high-spreading canopy at the beginning of fructification, XR11003 nozzle favoured the reduction of PLB infestation. Both spray volume adjustment systems enabled the same level of protection of tomato against PLB, which could result from alternate application of systemic and contact fungicides. Polyalkyleneoxide modified heptamethyltrisiloxane adjuvant, which causes siginificant increase in wetting and droplet spreading, facilitated the reduction of tomato PLB infestation during the application of fungicides using an IDKT12003 nozzle.

  9. Preliminary analysis of variability in concentration of fine particulate matter - PM1.0, PM2.5 and PM10 in area of Poznań city

    Directory of Open Access Journals (Sweden)

    Sówka Izabela

    2018-01-01

    Full Text Available It is commonly known, that suspended particulate matter pose a threat to human life and health, negatively influence the flora, climate and also materials. Especially dangerous is the presence of high concentration of particulate matter in the area of cities, where density of population is high. The research aimed at determining the variability of suspended particulate matter concentration (PM1.0, PM2.5 and PM10 in two different thermal seasons, in the area of Poznań city. As a part of carried out work we analyzed the variability of concentrations and also performed a preliminary analysis of their correlation. Measured concentrations of particulate matter were contained within following ranges: PM10 – 8.7-69.6 μg/m3, PM2.5 – 2.2-88.5 μg/m3, PM1.0 – 2.5-22.9 μg/m3 in the winter season and 1.0-42.8 μg/m3 (PM10, 1.2-40.3 μg/m3 (PM2.5 and 2.7-10.4 (PM1.0 in the summer season. Preliminary correlative analysis indicated interdependence between the temperature of air, the speed of wind and concentration of particulate matter in selected measurement points. The values of correlation coefficients between the air temperature, speed of wind and concentrations of particulate matter were respectively equal to: for PM10: -0.59 and -0.55 (Jana Pawła II Street, -0.53 and -0.53 (Szymanowskiego Street, for PM2.5: -0.60 and -0.53 (Jana Pawła II Street and for PM1.0 -0.40 and -0.59 (Jana Pawła II Street.

  10. Shape modification for decreasing the spring stiffness of double-plate nozzle type spacer grid spring

    International Nuclear Information System (INIS)

    Lee, K. H.; Kang, H. S.; Song, K. N.; Yun, K. H.; Kim, H. K.

    2001-01-01

    Nozzle of the double-plated grid plays the role of the spirng to support a fuel rod as well as the coolant path in grid. The nozzle was known to be necessary to reduce the spring stiffness for supporting performance. In this study, the contact analysis between the fuel rod and the newly designed nozzle was performed by ABAQUS computer code to propose the preferable shape in term of spring performance. Two small cut at the upper and lower part of the nozzle appeared to have a minor effect in decreasing the nozzle stiffness. A long slot at the center of the nozzle was turned out not only to decrease the spring constant as desired but also to increase the elastic displacement

  11. Method and apparatus for removably mounting a top nozzle on a nuclear reactor fuel assembly

    International Nuclear Information System (INIS)

    Wilson, J.F.; Gjertsen, R.K.; Schallenberger, J.M.

    1986-01-01

    In a fuel assembly having a top nozzle and control rod guide thimbles, a method is described of removably mounting the top nozzle on the ends of the guide thimbles, comprising the steps of: (a) releasably mating hollow outer sockets defined in the top nozzle with hollow inner sockets defined on the ends of the guide thimbles. The inner sockets are movable between compressed conditions for removing and inserting the inner sockets from and into the outer sockets in mounting and removing the top nozzle on and from the guide thimbles and expanded conditions for mating the inner and outer sockets together and the top nozzle on the guide thimbles; (b) supporting elongated locking tubes such that end portions thereof extend into the outer sockets defined in the top nozzle; and (c) moving all of the locking tubes at the same time between unlocking and locking positions to displace their end portions axially within the outer sockets between first and second locations

  12. Short-term relationship between meteorological variables and hip fractures: an analysis carried out in a health area of the Autonomous Region of Valencia, Spain (1996-2005).

    Science.gov (United States)

    Tenías, José María; Estarlich, Marisa; Fuentes-Leonarte, Virginia; Iñiguez, Carmen; Ballester, Ferran

    2009-10-01

    Diverse studies have shown a seasonal influence on the incidence of hip fracture (HF), possibly associated with adverse meteorological conditions. In this paper, we present an analysis of the short-term relationship between meteorological conditions and the incidence of HF in people over 45 years of age living in a Mediterranean climate zone. HF cases admitted to the two reference hospitals in the health area were selected. The meteorological variables (temperature, relative humidity, rain, wind, and other conditions) were obtained from a weather station centrally located within the area under study. The trend and seasonality of the time series were analyzed with the aid of Poisson regression modeling. The relationship between the incidence of a hip fracture and the meteorological conditions, both on the same day and on the day previous to the patient's admission to the hospital were correlated in a case-crossover analysis with the control periods selected in accordance with two different methods of approximation (symmetric and semi-metric). The results were analyzed for different subgroups defined by age (older or younger than 75 years of age) and sex of subject and by type of fracture (cervical or pertrochanteric). 2121 patients admitted for HF were selected. Of these, 1598 (75.3%) were women and 523 (24.7%) were men. The average age of the subjects was 80, with patients ranging from 45-99 years of age. The time/weather series showed a positive tendency, with a greater occurrence of cases in the autumn and winter months. The case-crossover analysis showed a significant relationship between the daily duration of wind and the incidence of HFs. Divided into quartiles, the windiest days (quartile 4) were associated with a 32% increased risk of HF (OR 1.32 CI 95% 1.10-1.58) with respect to the calmest days (quartile 1), especially in patients under 75 (OR 1.53; CI 95% 1.02-2.29). The remaining meteorological variables were not associated in any significant fashion

  13. A CFD-based aerodynamic design procedure for hypersonic wind-tunnel nozzles

    Science.gov (United States)

    Korte, John J.

    1993-01-01

    A new procedure which unifies the best of current classical design practices, computational fluid dynamics (CFD), and optimization procedures is demonstrated for designing the aerodynamic lines of hypersonic wind-tunnel nozzles. The new procedure can be used to design hypersonic wind tunnel nozzles with thick boundary layers where the classical design procedure has been shown to break down. An efficient CFD code, which solves the parabolized Navier-Stokes (PNS) equations using an explicit upwind algorithm, is coupled to a least-squares (LS) optimization procedure. A LS problem is formulated to minimize the difference between the computed flow field and the objective function, consisting of the centerline Mach number distribution and the exit Mach number and flow angle profiles. The aerodynamic lines of the nozzle are defined using a cubic spline, the slopes of which are optimized with the design procedure. The advantages of the new procedure are that it allows full use of powerful CFD codes in the design process, solves an optimization problem to determine the new contour, can be used to design new nozzles or improve sections of existing nozzles, and automatically compensates the nozzle contour for viscous effects as part of the unified design procedure. The new procedure is demonstrated by designing two Mach 15, a Mach 12, and a Mach 18 helium nozzles. The flexibility of the procedure is demonstrated by designing the two Mach 15 nozzles using different constraints, the first nozzle for a fixed length and exit diameter and the second nozzle for a fixed length and throat diameter. The computed flow field for the Mach 15 least squares parabolized Navier-Stokes (LS/PNS) designed nozzle is compared with the classically designed nozzle and demonstrates a significant improvement in the flow expansion process and uniform core region.

  14. Measurement of the residual stresses in a PWR Control Rod Drive Mechanism nozzle

    OpenAIRE

    Coules, Harry; Smith, David

    2018-01-01

    Residual stress in the welds that attach Control Rod Drive Mechanism nozzles into the upper head of a PWR reactor vessel can influence the vessel's structural integrity and initiate Primary Water Stress Corrosion Cracking. PWSCC at Alloy 600 CRDM nozzles has caused primary coolant leakage in operating PWRs. We have used Deep Hole Drilling to characterise residual stresses in a PWR vessel head. Measurements of the internal cladding and nozzle attachment weld showed that although modest tensile...

  15. The Effect of Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions

    Science.gov (United States)

    2014-10-01

    The Effect of Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions by Matthew Kurman, Luis Bravo, Chol-Bum Kweon...Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions Matthew Kurman, Luis Bravo, and Chol-Bum Kweon Vehicle Technology...March 2014 4. TITLE AND SUBTITLE The Effect of Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions 5a. CONTRACT NUMBER 5b

  16. INVESTIGATION OF FLOW BEHAVIOR IN MINIMUM QUANTITY LUBRICATION NOZZLE FOR END MILLING PROCESSES

    OpenAIRE

    M.S. Najiha; M.M.Rahman; A.R. Yusoff; K. Kadirgama

    2012-01-01

    Minimum quantity lubrication (MQL) is a sustainable manufacturing technique that has replaced conventional flooded lubrication methods and dry machining. In the MQL technique, the lubricant is sprayed onto the friction surfaces through nozzles through small pneumatically-operated pumps. This paper presents an investigation into the flow behavior of the lubricant and air mixture under certain pressures at the tip of a nozzle specially designed for MQL. The nozzle used is an MQL stainless steel...

  17. Estimation of Efficiency of the Cooling Channel of the Nozzle Blade of Gas-Turbine Engines

    Science.gov (United States)

    Vikulin, A. V.; Yaroslavtsev, N. L.; Zemlyanaya, V. A.

    2018-02-01

    The main direction of improvement of gas-turbine plants (GTP) and gas-turbine engines (GTE) is increasing the gas temperature at the turbine inlet. For the solution of this problem, promising systems of intensification of heat exchange in cooled turbine blades are developed. With this purpose, studies of the efficiency of the cooling channel of the nozzle blade in the basic modification and of the channel after constructive measures for improvement of the cooling system by the method of calorimetry in a liquid-metal thermostat were conducted. The combined system of heat-exchange intensification with the complicated scheme of branched channels is developed; it consists of a vortex matrix and three rows of inclined intermittent trip strips. The maximum value of hydraulic resistance ξ is observed at the first row of the trip strips, which is connected with the effect of dynamic impact of airflow on the channel walls, its turbulence, and rotation by 117° at the inlet to the channels formed by the trip strips. These factors explain the high value of hydraulic resistance equal to 3.7-3.4 for the first row of the trip strips. The obtained effect was also confirmed by the results of thermal tests, i.e., the unevenness of heat transfer on the back and on the trough of the blade is observed at the first row of the trip strips, which amounts 8-12%. This unevenness has a fading character; at the second row of the trip strips, it amounts to 3-7%, and it is almost absent at the third row. At the area of vortex matrix, the intensity of heat exchange on the blade back is higher as compared to the trough, which is explained by the different height of the matrix ribs on its opposite sides. The design changes in the nozzle blade of basic modification made it possible to increase the intensity of heat exchange by 20-50% in the area of the vortex matrix and by 15-30% on the section of inclined intermittent trip strips. As a result of research, new criteria dependences for the

  18. Variability in chemical composition of Vitis vinifera cv Mencía from different geographic areas and vintages in Ribeira Sacra (NW Spain).

    Science.gov (United States)

    Vilanova, M; Rodríguez, I; Canosa, P; Otero, I; Gamero, E; Moreno, D; Talaverano, I; Valdés, E

    2015-02-15

    A chemical study was conducted from 2009 to 2012 to examine spatial and seasonal variability of red Vitis vinifera Mencía located in different geographic areas (Amandi, Chantada, Quiroga-Bibei, Ribeiras do Sil and Ribeiras do Miño) from NW Spain. Mencía samples were analysed for phenolic, (flavan-3-ols, flavonols, anthocyanins, acids and resveratrol), nitrogen (TAC, TAN, YAN and TAS) and volatiles compounds (alcohols, C6 compounds, ethyl esters, terpenes, aldehydes, acids, lactones, volatile phenols and carbonyl compounds) by GC-MS and HPLC. Results showed that the composition of Mencía cultivar was more affected by the vintage than the geographic area. The amino acid composition was less affected by both geographic origin and vintage, showing more varietal stability. Application of Principal Component Analysis (PCA) to experimental data showed a good separation of Mencía grape according to geographical origin and vintages. PCA also showed high correlations between the ripening ratio and C6 compounds, resveratrol and carbonyl compounds. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Variability in oocyte size and batch fecundity in anchoveta (Engraulis ringens, Jenyns 1842 from two spawning areas off the Chilean coast

    Directory of Open Access Journals (Sweden)

    Elson M. Leal

    2009-03-01

    Full Text Available Utilising histological preparations of ovaries from Engraulis ringens females collected in two contrasting spawning habitats along the Chilean coast, we assess the variability in oocyte size and batch fecundity during the peak spawning seasons in three years. The effects of female size (length and weight, batch fecundity and mean sea surface temperature on oocyte size were also examined. Results showed larger oocytes and lower batch fecundity in females from the southern area. Oocyte volume differences persisted inter-annually and were not explained by differences in female sizes. Since ovary weight was similar between areas, the cost of producing larger oocytes in the south population seems to be a fecundity reduction. The latitudinal variations in oocyte number and size seem to be determined by the predominant environmental conditions in each habitat. Hence, female E. ringens seem to adapt their reproductive tactics by producing eggs sizes and quantities that favour survival of their offspring under the environmental conditions in which they are to develop.

  20. Hydrogen extraction from liquid lithium-lead alloy by bubbling with rotational jet nozzle

    International Nuclear Information System (INIS)

    Xie Bo; Yang Tongzai; Guan Rui; Weng Kuiping

    2010-01-01

    The technology of tritium extraction from lithium-lead alloy has been simulated, hydrogen extraction from lithium-lead alloy by bubbling with rotational jet nozzle being used to simulate tritium in the study based on the introduction of fluid dynamics to establish algebraic model. The results show that the higher than lithium-lead melting temperature, the higher cumulative hydrogen extraction efficiency, and gas holdup of bubble column is little affected by the impeller diameter. Gas holdup when using small aperture is slightly higher when using large aperture only at a high helium flow rate, but the smaller the aperture, the greater the bubble surface area, and a marked increase in intensity of flow circulation for liquid lithium-lead with the increase of helium flow rate, hydrogen extraction rate increases too. Moreover, influence of the jet rotational velocity on hydrogen extraction is limited. (authors)

  1. Experimental stress analysis of the attachment region of hemispherical shells with attached nozzles. Part 2b. Radial nozzle 7.875 in. O.D.--7.500 in. I.D. 10.00 in. penetration

    International Nuclear Information System (INIS)

    Maxwell, R.L.; Holland, R.W.; Stengl, G.R.

    1970-06-01

    The report presents the results of investigations conducted on a hemisphere with a radial nozzle of 7.875'' O.D. and 7.500'' I.D. and 10'' penetration into the hemisphere. Stress values were determined for the following five types of loadings: (1) internal pressure applied to the hemisphere and nozzle assembly, (2) an axial load applied collinear with nozzle, (3) a pure bending moment, or axial couple, applied to the nozzle, (4) a transverse or shear load applied normal to the nozzle, and (5) a pure torque applied in the radial plane of the nozzle

  2. High performance Solid Rocket Motor (SRM) submerged nozzle/combustion cavity flowfield assessment

    Science.gov (United States)

    Freeman, J. A.; Chan, J. S.; Murph, J. E.; Xiques, K. E.

    1987-01-01

    Two and three dimensional internal flowfield solutions for critical points in the Space Shuttle solid rocket booster burn time were developed using the Lockheed Huntsville GIM/PAID Navier-Stokes solvers. These perfect gas, viscous solutions for the high performance motor characterize the flow in the aft segment and nozzle of the booster. Two dimensional axisymmetric solutions were developed at t = 20 and t = 85 sec motor burn times. The t = 85 sec solution indicates that the aft segment forward inhibitor stub produces vortices with are shed and convected downwards. A three dimensional 3.5 deg gimbaled nozzle flowfield solution was developed for the aft segment and nozzle at t = 9 sec motor burn time. This perfect gas, viscous analysis, provided a steady state solution for the core region and the flow through the nozzle, but indicated that unsteady flow exists in the region under the nozzle nose and near the flexible boot and nozzle/case joint. The flow in the nozzle/case joint region is characterized by low magnitude pressure waves which travel in the circumferential direction. From the two and three dimensional flowfield calculations presented it can be concluded that there is no evidence from these results that steady state gas dynamics is the primary mechanism resulting in the nozzle pocketing erosion experienced on SRM nozzles 8A or 17B. The steady state flowfield results indicate pocketing erosion is not directly initiated by a steady state gas dynamics phenomenon.

  3. An Interactive Method of Characteristics Java Applet to Design and Analyze Supersonic Aircraft Nozzles

    Science.gov (United States)

    Benson, Thomas J.

    2014-01-01

    The Method of Characteristics (MOC) is a classic technique for designing supersonic nozzles. An interactive computer program using MOC has been developed to allow engineers to design and analyze supersonic nozzle flow fields. The program calculates the internal flow for many classic designs, such as a supersonic wind tunnel nozzle, an ideal 2D or axisymmetric nozzle, or a variety of plug nozzles. The program also calculates the plume flow produced by the nozzle and the external flow leading to the nozzle exit. The program can be used to assess the interactions between the internal, external and plume flows. By proper design and operation of the nozzle, it may be possible to lessen the strength of the sonic boom produced at the rear of supersonic aircraft. The program can also calculate non-ideal nozzles, such as simple cone flows, to determine flow divergence and nonuniformities at the exit, and its effect on the plume shape. The computer program is written in Java and is provided as free-ware from the NASA Glenn central software server.

  4. Direct Numerical Simulation of Hypersonic Turbulent Boundary Layer inside an Axisymmetric Nozzle

    Science.gov (United States)

    Huang, Junji; Zhang, Chao; Duan, Lian; Choudhari, Meelan M.

    2017-01-01

    As a first step toward a study of acoustic disturbance field within a conventional, hypersonic wind tunnel, direct numerical simulations (DNS) of a Mach 6 turbulent boundary layer on the inner wall of a straight axisymmetric nozzle are conducted and the results are compared with those for a flat plate. The DNS results for a nozzle radius to boundary-layer thickness ratio of 5:5 show that the turbulence statistics of the nozzle-wall boundary layer are nearly unaffected by the transverse curvature of the nozzle wall. Before the acoustic waves emanating from different parts of the nozzle surface can interfere with each other and undergo reflections from adjacent portions of the nozzle surface, the rms pressure fluctuation beyond the boundary layer edge increases toward the nozzle axis, apparently due to a focusing effect inside the axisymmetric configuration. Spectral analysis of pressure fluctuations at both the wall and the freestream indicates a similar distribution of energy content for both the nozzle and the flat plate, with the peak of the premultiplied frequency spectrum at a frequency of [(omega)(delta)]/U(sub infinity) approximately 6.0 inside the free stream and at [(omega)(delta)]/U(sub infinity) approximately 2.0 along the wall. The present results provide the basis for follow-on simulations involving reverberation effects inside the nozzle.

  5. A preliminary investigation of the design parameters of an air induction nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Vashahi, Foad; Ra, Sothea; Lee, Jeekeun [Chonbuk National University, Jeonju (Korea, Republic of); Choi, Yong [National Academy of Agricultural Science, Wanju (Korea, Republic of)

    2017-07-15

    In the present study, an experimental study on design parameters of an air induction nozzle was performed. These nozzles are capable of producing large size droplets, including microbubbles, which in turn results in high drift reduction. A magnified 2D version of an air induction nozzle was designed and manufactured. The manufactured geometries have the ability to be disassembled easily, thus several geometrical parameters are replaced sequentially. The effects of a venturi throat, air orifices and discharge orifice diameters along with the length of the mixing chamber are analyzed. Analysis of the parameters revealed their strength of prediction on the air liquid ratio and the nozzle performance.

  6. Development of built-in debris-filter bottom nozzle for PWR fuel assemblies

    International Nuclear Information System (INIS)

    Juntaro Shimizu; Kazuki Monaka; Masaji Mori; Kazuo Ikeda

    2005-01-01

    Mitsubishi Heavy Industries, Ltd. (MHI) has worked to improve the capability of anti debris bottom nozzle for a PWR fuel assembly. The Current debris filter bottom nozzle (DFBN) having 4mm diameter flow holes can capture the larger size of debris than the flow hole inner diameter. MHI has completed the development of the built-in debris filter bottom nozzle, which is the new idea of the debris-filter for high burnup (55GWd/t assembly average burnup). Built-in debris filter bottom nozzle consists of the blades and nozzle body. The blades made from inconel strip are embedded and welded on the grooved top surface of the bottom nozzle adapter plate. A flow hole is divided by the blade and the trap size of the debris is reduced. Because the blades block the coolant flow, it was anticipated to increase the pressure loss of the nozzle, however, adjusting the relation between blade and taper shape of the flow hole, the pressure loss has been successfully maintained the satisfactory level. Grooves are cut on the nozzle plate; nevertheless, the additional skirts on the four sides of the nozzle compensate the structural strength. (authors)

  7. Stress analysis of the HFIR HB-2 and HB-3 beam tube nozzles

    International Nuclear Information System (INIS)

    Williams, P.T.

    1998-08-01

    The results of three-dimensional linear elastic stress analyses of the HFIR HB-2 and HB-3 nozzles are presented in this report. Finite element models were developed using the PATRAN pre-processing code and translated into ABAQUS input file format. A scoping analysis using simple geometries with internal pressure loading was carried out to assess the capabilities of the ABAQUS/Standard code to calculate maximum principal stress distributions within cylinders with and without holes. These scoping calculations were also used to provide estimates for the variation in tangential stress around the rim of a nozzle using the superposition of published closed-form solutions for the stress around a hole in an infinite flat plate under uniaxial tension. From the results of the detailed finite element models, peak stress concentration factors (based on the maximum principal stresses in tension) were calculated to be 3.0 for the HB-2 nozzle and 2.8 for the HB-3 nozzle. Submodels for each nozzle were built to calculate the maximum principal stress distribution in the weldment region around the nozzle, where displacement boundary conditions for the submodels were automatically calculated by ABAQUS using the results of the global nozzle models. Maximum principal stresses are plotted and tabulated for eight positions around each nozzle and nozzle weldment

  8. Interior flow and near-nozzle spray development in a marine-engine diesel fuel injector

    Science.gov (United States)

    Hult, J.; Simmank, P.; Matlok, S.; Mayer, S.; Falgout, Z.; Linne, M.

    2016-04-01

    A consolidated effort at optically characterising flow patterns, in-nozzle cavitation, and near-nozzle jet structure of a marine diesel fuel injector is presented. A combination of several optical techniques was employed to fully transparent injector models, compound metal-glass and full metal injectors. They were all based on a common real-scale dual nozzle hole geometry for a marine two-stroke diesel engine. In a stationary flow rig, flow velocities in the sac-volume and nozzle holes were measured using PIV, and in-nozzle cavitation visualized using high-resolution shadowgraphs. The effect of varying cavitation number was studied and results compared to CFD predictions. In-nozzle cavitation and near-nozzle jet structure during transient operation were visualized simultaneously, using high-speed imaging in an atmospheric pressure spray rig. Near-nozzle spray formation was investigated using ballistic imaging. Finally, the injector geometry was tested on a full-scale marine diesel engine, where the dynamics of near-nozzle jet development was visualized using high-speed shadowgraphy. The range of studies focused on a single common geometry allows a comprehensive survey of phenomena ranging from first inception of cavitation under well-controlled flow conditions to fuel jet structure at real engine conditions.

  9. Proposed Flight Research of a Dual-Bell Rocket Nozzle Using the NASA F-15 Airplane

    Science.gov (United States)

    Jones, Daniel S.; Bui, Trong T.; Ruf, Joseph H.

    2013-01-01

    For more than a half-century, several types of altitude-compensating rocket nozzles have been proposed and analyzed, but very few have been adequately tested in a relevant flight environment. One type of altitude-compensating nozzle is the dual-bell rocket nozzle, which was first introduced into literature in 1949. Despite the performance advantages that have been predicted, both analytically and through static test data, the dual-bell nozzle has still not been adequately tested in a relevant flight environment. This paper proposes a method for conducting testing and research with a dual-bell rocket nozzle in a flight environment. We propose to leverage the existing NASA F-15 airplane and Propulsion Flight Test Fixture as the flight testbed, with the dual-bell nozzle operating during captive-carried flights, and with the nozzle subjected to a local flow field similar to that of a launch vehicle. The primary objective of this effort is not only to advance the technology readiness level of the dual-bell nozzle, but also to gain a greater understanding of the nozzle mode transitional sensitivity to local flow-field effects, and to quantify the performance benefits with this technology. The predicted performance benefits are significant, and may result in reducing the cost of delivering payloads to low-Earth orbit.

  10. INVESTIGATION OF FLOW BEHAVIOR IN MINIMUM QUANTITY LUBRICATION NOZZLE FOR END MILLING PROCESSES

    Directory of Open Access Journals (Sweden)

    M.S. Najiha

    2012-12-01

    Full Text Available Minimum quantity lubrication (MQL is a sustainable manufacturing technique that has replaced conventional flooded lubrication methods and dry machining. In the MQL technique, the lubricant is sprayed onto the friction surfaces through nozzles through small pneumatically-operated pumps. This paper presents an investigation into the flow behavior of the lubricant and air mixture under certain pressures at the tip of a nozzle specially designed for MQL. The nozzle used is an MQL stainless steel nozzle, 6.35 mm in diameter. Computational fluid dynamics is used to determine the flow pattern at the tip of the nozzle where the lubricant and compressed air are mixed to form a mist. The lubricant volume flow is approximately 0.08 ml/cycle of the pump. A transient, pressure-based, three-dimensional analysis is performed with a viscous, realizable k-ε model. The results are obtained in the form of vector plots and flow fields. The flow mixing at the tip of the nozzle is wholly shown through the flow fields and vector plots. This study provides an insight into the flow distribution at the tip of the nozzle for a certain pressure to aid modifications in the design of the nozzle for future MQL studies. It attainable aids to determine the correct pressure for the air jet at the nozzle tip.

  11. Fracture mechanics evaluation of LOFT lower plenum injection nozzle

    International Nuclear Information System (INIS)

    Nagata, P.K.; Reuter, W.G.

    1977-01-01

    An analysis to establish whether or not a leak-before-break concept would apply to the LOFT lower plenum injection nozzle is described. The analysis encompassed the structure from the inlet side of valve V-2170 to the lower plenum nozzle-to-reactor vessel weld on the left side of the emergency core cooling system (ECCS). The defect that was assumed to exist was of such a size that the probability of its being missed by the applicable inspection technique was near zero. The Inconel 600 nozzle forging with an initial assumed defect size of 0.64 cm (0.25 in.) deep would behave as follows: (1) the axially oriented defect would result in leak before rupture (the number of cycles to rupture was 11,000), (2) the circumferentially oriented defect would result in a rupture before leak. The number of cycles to failure would be in excess of 14,000. Based on the conservative assumption that the thermal stresses were membrane stresses as opposed to a bending stress, the following were found. For the Inconel 82 weld metal (thickness of 1.3 cm [0.53 in.]) and AISI 316 SST valve body, with an initial assumed defect of 0.25 cm (0.1 in.), the crack would grow through the thickness in a minimum of 3950 cycles and to a critical rupture crack length of 5.1 cm (2.0 in.) in an additional 80 cycles. The Inconel 82 weld metal at the shell body (thickness of 9.7 cm or 3.8 in.) with an assumed defect 1.3 cm (0.5 in.) deep would fail in 334 cycles. Calculations made assuming a linear stress gradient instead of the above-mentioned flat distribution through the wall indicated that the number of stress cycles increased to 2200

  12. Numerical modelling of the jet nozzle enrichment process

    International Nuclear Information System (INIS)

    Vercelli, P.

    1983-01-01

    A numerical model was developed for the simulation of the isotopic enrichment produced by the jet nozzle process. The flow was considered stationary and under ideal gas conditions. The model calculates, for any position of the skimmer piece: (a) values of radial mass concentration profiles for each isotopic species and (b) values of elementary separation effect (Σ sub(A)) and uranium cut (theta). The comparison of the numerical results obtained with the experimental values given in the literature proves the validity of the present work as an initial step in the modelling of the process. (Author) [pt

  13. Prevalence study of cognitive impairment and its associated sociodemographic variables using mini-mental status examination among elderly population residing in field practice areas of a medical college

    Directory of Open Access Journals (Sweden)

    Rakesh M Patel

    2018-01-01

    Full Text Available Context: The world is aging rapidly through “demographic transition.” The aging leads to CI Refers as Cognitive Impairment (CI – a risk factor for dementia. A community-based cross-sectional study was conducted among the elderly aged ≥50 years. Objectives: The objective of the study is to estimate the prevalence of cognitive dysfunction among the elderly and to identify the associated sociodemographic variables. Settings and Design: This was a community-based cross-sectional study in rural and urban field areas of a medical college. Subjects and Methods: Participants aged ≥50 years were interviewed using a structured questionnaire and screened for cognitive dysfunction using Gujarati version of Mini-Mental Status Examination. A score of 23 out of 30 was taken as the cutoff. Written informed consent was obtained from participants. Statistical Analysis Used: Univariate and multivariate analyses were done using SPSS version 17 and Epi Info version 6 to identify significant variables. Results: Of 560 participants, 140 (25% had CI. Rural (27.6% and female (29.8% prevalence was higher than urban (18.5% and male (19.1% prevalence. On multivariate analysis, age ≥60 years (odds ratio [OR]: 2.98 and illiteracy (OR: 39.8 had significant positive association with outcome; being employed (OR: 0.18, living with spouse (OR: 0.07, and living with spouse and children (OR: 0.08 had significant negative association with outcome. Conclusions: CI – a precursor of dementia – has serious clinical and public health consequences. Awareness generation and capacity building of primary health-care workers and family caregivers are core control strategies.

  14. Small-scale variability of particulate matter and perception of air quality in an inner-city recreational area in Aachen, Germany

    Directory of Open Access Journals (Sweden)

    Bastian Paas

    2016-06-01

    Full Text Available Spatial micro-scale variability of particle mass concentrations is an important criterion for urban air quality assessment. In this study we present results from detailed spatio-temporal measurements in the urban roughness layer along with a survey to determine perceptions of citizens regarding air quality in an inner city park in Aachen, Germany. Particles were sampled with two different approaches in February, May, July and September 2014 using an optical particle counter at six fixed measurement locations, representing different degrees of outdoor particle exposure that can be experienced by a pedestrian walking in an intra-urban recreational area. A simulation of aerosol emissions induced by road traffic was conducted using the German reference dispersion model Austal2000. The mobile measurements revealed unexpected details in the distribution of urban particles with highest mean concentrations of PM(1;10$\\text{PM}_{(1;10}$ inside the green area 100 m away from bus routes (arithmetic mean: 22.5 μg m−3 and 18.9 μg m−3; geometric mean: 9.3 μg m−3 and 6.5 μg m−3, whereas measurement sites in close proximity to traffic lines showed far lower mean values (arithmetic mean: 7.5 μg m−3 and 8.7 μg m−3; geometric mean: 5.8 μg m−3 and 6.5 μg m−3. Concerning simulation results, motor traffic is still proved to be an important aerosol source in the area, although the corresponding concentrations declined rapidly as the distances to the line sources increased. Further analysis leads to the assumption that particularly coarse particles were emitted through diffuse sources e.g. on the ability of surfaces to release particles by resuspension which were dominantly apparent in measured PM(1;10$\\text{PM}_{(1;10}$ and PM(0.25;10$\\text{PM}_{(0.25;10}$ data. The contribution of diffuse particle sources and urban background transport to local PM(0.25;10$\\text{PM}_{(0.25;10}$ concentrations inside the

  15. Transient Side Load Analysis of Out-of-Round Film-Cooled Nozzle Extensions

    Science.gov (United States)

    Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike

    2012-01-01

    There was interest in understanding the impact of out-of-round nozzle extension on the nozzle side load during transient startup operations. The out-of-round nozzle extension could be the result of asymmetric internal stresses, deformation induced by previous tests, and asymmetric loads induced by hardware attached to the nozzle. The objective of this study was therefore to computationally investigate the effect of out-of-round nozzle extension on the nozzle side loads during an engine startup transient. The rocket engine studied encompasses a regeneratively cooled chamber and nozzle, along with a film cooled nozzle extension. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and transient inlet boundary flow properties derived from an engine system simulation. Six three-dimensional cases were performed with the out-of-roundness achieved by three different degrees of ovalization, elongated on lateral y and z axes: one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The results show that the separation line jump was the primary source of the peak side loads. Comparing to the peak side load of the perfectly round nozzle, the peak side loads increased for the slightly and more ovalized nozzle extensions, and either increased or decreased for the two significantly ovalized nozzle extensions. A theory based on the counteraction of the flow destabilizing effect of an exacerbated asymmetrical flow caused by a lower degree of ovalization, and the flow stabilizing effect of a more symmetrical flow, created also by ovalization, is presented to explain the observations obtained in this effort.

  16. Aerodynamic characteristics of a large-scale semispan model with a swept wing and an augmented jet flap with hypermixing nozzles. [Ames 40- by 80-Foot Wind Tunnel and Static Test Facility

    Science.gov (United States)

    Aiken, T. N.; Falarski, M. D.; Koenin, D. G.

    1979-01-01

    The aerodynamic characteristics of the augmentor wing concept with hypermixing primary nozzles were investigated. A large-scale semispan model in the Ames 40- by 80-Foot Wind Tunnel and Static Test Facility was used. The trailing edge, augmentor flap system occupied 65% of the span and consisted of two fixed pivot flaps. The nozzle system consisted of hypermixing, lobe primary nozzles, and BLC slot nozzles at the forward inlet, both sides and ends of the throat, and at the aft flap. The entire wing leading edge was fitted with a 10% chord slat and a blowing slot. Outboard of the flap was a blown aileron. The model was tested statically and at forward speed. Primary parameters and their ranges included angle of attack from -12 to 32 degrees, flap angles of 20, 30, 45, 60 and 70 degrees, and deflection and diffuser area ratios from 1.16 to 2.22. Thrust coefficients ranged from 0 to 2.73, while nozzle pressure ratios varied from 1.0 to 2.34. Reynolds number per foot varied from 0 to 1.4 million. Analysis of the data indicated a maximum static, gross augmentation of 1.53 at a flap angle of 45 degrees. Analysis also indicated that the configuration was an efficient powered lift device and that the net thrust was comparable with augmentor wings of similar static performance. Performance at forward speed was best at a diffuser area ratio of 1.37.

  17. BWR feedwater nozzle and control rod drive return line nozzle cracking: resolution of generic technical activity A-10. Technical report

    International Nuclear Information System (INIS)

    Snaider, R.

    1980-11-01

    This report summarizes work performed by the NRC staff in the resolution of Generic Technical Activity A-10, 'BWR Nozzle Cracking'. Generic Technical Activity A-10 is one of the generic technical subjects designated as 'unresolved safety issues' pursuant to Section 210 of the Energy Reorganization Act of 1974. The report describes the technical issues, the technical studies and analyses performed by the General Electric Company and the NRC staff, the staff's technical positions based on these studies, and the staff's plans for continued implementation of its technical positions. It also provides information for further work to resolve the non-destructive examination issue

  18. Experimental stress analysis of the attachment region of hemispherical shells with attached nozzles. Part 5c. Nonradial nozzle at 22-1/2 degrees 2.625 in. O.D.--2.5000 in. I.D., zero penetration

    International Nuclear Information System (INIS)

    Maxwell, R.L.; Holland, R.W.

    1975-06-01

    A continuing series of investigations has been conducted to determine experimentally the stress patterns for the junction region of spherical shells with radially and non-radially attached nozzles when subjected to internal pressure and various types of loadings on the nozzles. Results of the investigations conducted on a nonradially attached nozzle of 2.625 in.-OD, 2.500 in. ID, and finished flush with the inner surface of the hemisphere are reported. The nozzle was inclined at 22 1 / 2 0 from a radial axis. Stress values for the following types of loadings are tabulated: internal pressure applied to the hemisphere and nozzle assembly; an axial load applied collinear with nozzle; a pure torque applied in the radial plane of the nozzle; and a pure bending moment or axial couple applied in various axial planes of the nozzle. Various stress vs. profile curves are presented. These curves present the tabulated stress data in graphical format. (U.S.)

  19. UT inspection of nozzles by 3D raytracing

    International Nuclear Information System (INIS)

    Isenberg, J.; Koshy, M.; Carcione, L.

    2004-01-01

    This paper documents how we have adapted 3D geometric modeling and ray tracing to support design and verification of wedges and preparation of coverage maps for ultrasonic inspection of BWR nozzles. This software is capable of addressing a broad range of modeling issues, including ray tracing in completely general 3D objects comprised of blocky, transversely isotropic material. However, to capitalize on the full range of capability usually requires an investment of time on the part of users. To make 3D modeling accessible to users who have time-urgent requirements or who do not need to utilize the full capabilities of the software, we have developed specialized applications in which restrictions on generality are accepted in exchange for easy access to model building, wedge design and coverage maps for detecting flaws in the bore and inner blend regions of nozzles. This is done by providing partially-completed, parametrized models which give the user latitude to generate general models within a fixed framework. We also provide a graphical user interface which anticipates certain tasks that a user will wish to undertake; other tasks may readily be added. (author)

  20. Evolutionary Optimization of Centrifugal Nozzles for Organic Vapours

    Science.gov (United States)

    Persico, Giacomo

    2017-03-01

    This paper discusses the shape-optimization of non-conventional centrifugal turbine nozzles for Organic Rankine Cycle applications. The optimal aerodynamic design is supported by the use of a non-intrusive, gradient-free technique specifically developed for shape optimization of turbomachinery profiles. The method is constructed as a combination of a geometrical parametrization technique based on B-Splines, a high-fidelity and experimentally validated Computational Fluid Dynamic solver, and a surrogate-based evolutionary algorithm. The non-ideal gas behaviour featuring the flow of organic fluids in the cascades of interest is introduced via a look-up-table approach, which is rigorously applied throughout the whole optimization process. Two transonic centrifugal nozzles are considered, featuring very different loading and radial extension. The use of a systematic and automatic design method to such a non-conventional configuration highlights the character of centrifugal cascades; the blades require a specific and non-trivial definition of the shape, especially in the rear part, to avoid the onset of shock waves. It is shown that the optimization acts in similar way for the two cascades, identifying an optimal curvature of the blade that both provides a relevant increase of cascade performance and a reduction of downstream gradients.

  1. Analysis of cracked pressure vessel nozzles by finite elements

    International Nuclear Information System (INIS)

    Reynen, J.

    1975-01-01

    The paper describes various algorithms, their computer implementations and relative merits to define in an effective way strain energy release rates along the tip front of arbitrary 3D cracks under arbitrary load including thermal strains. These techniques are basically equivalent to substructuring techniques and consequently they can be implemented to any FEM program able to deal with the data handling problems of the substructuring technique. Special finite elements with a built-in stress-singularity are not necessary although their use contributes to accuracy and the mesh can be coarser. Examples are given carried out with a substructure version of the BERSAFE system. These examples include a corner crack in a pressure vessel nozzle loaded by internal pressure and by thermal stresses. Although not of any fundamental importance, in practice the difficulties consist in generating an appropriate mesh to represent the crack front. For the example of the corner crack in a nozzle the problem has been solved by developing a special purpose mesh generation program (EURCRACK)

  2. Experimental investigation of a two-phase nozzle flow

    International Nuclear Information System (INIS)

    Kedziur, F.; John, H.; Loeffel, R.; Reimann, J.

    1980-07-01

    Stationary two-phase flow experiments with a convergent nozzle are performed. The experimental results are appropriate to validate advanced computer codes, which are applied to the blowdown-phase of a loss-of-coolant accident (LOCA). The steam-water experiments present a broad variety of initial conditions: the pressure varies between 2 and 13 MPa, the void fraction between 0 (subcooled) and about 80%, a great number of critical as well as subcritical experiments with different flow pattern is investigated. Additional air-water experiments serve for the separation of phase transition effects. The transient acceleration of the fluid in the LOCA-case is simulated by a local acceleration in the experiment. The layout of the nozzle and the applied measurement technique allow for a separate testing of blowdown-relevant, physical models and the determination of empirical model parameters, respectively. The measured quantities are essentially the mass flow rate, quality, axial pressure and temperature profiles as well as axial and radial density/void profiles obtained by a γ-ray absorption device. Moreover, impedance probes and a pitot probe are used. Observed phenomena like a flow contraction, radial pressure and void profiles as well as the appearance of two chocking locations are described, because their examination is rather instructive about the refinement of a program. The experimental facilities as well as the data of 36 characteristic experiments are documented. (orig.) [de

  3. Sludge mobilization with submerged nozzles in horizontal cylindrical tanks

    International Nuclear Information System (INIS)

    Hylton, T.D.; Cummins, R.L.; Youngblood, E.L.; Perona, J.J.

    1995-10-01

    The Melton Valley Storage Tanks (MVSTs) and the evaporator service tanks at the Oak Ridge National Laboratory (ORNL) are used for the collection and storage of liquid low-level waste (LLLW). Wastes collected in these tanks are typically acidic when generated and are neutralized with sodium hydroxide to protect the tanks from corrosion; however, the high pH of the solution causes the formation of insoluble compounds that precipitate. These precipitates formed a sludge layer approximately 0.6 to 1.2 m (2 to 4 ft) deep in the bottom of the tanks. The sludge in the MVSTs and the evaporator service tanks will eventually need to be removed from the tanks and treated for final disposal or transferred to another storage facility. The primary options for removing the sludge include single-point sluicing, use of a floating pump, robotic sluicing, and submerged-nozzle sluicing. The objectives of this study were to (1) evaluate the feasibility of submerged-nozzle sluicing in horizontal cylindrical tanks and (2) obtain experimental data to validate the TEMPEST (time-dependent, energy, momentun, pressure, equation solution in three dimensions) computer code

  4. Acoustic Investigation of Jet Mixing Noise in Dual Stream Nozzles

    Science.gov (United States)

    Khavaran, Abbas; Dahl, Milo D.

    2012-01-01

    In an earlier study, a prediction model for jet noise in dual stream jets was proposed that is founded on velocity scaling laws in single stream jets and similarity features of the mean velocity and turbulent kinetic energy in dual stream flows. The model forms a composite spectrum from four component single-stream jets each believed to represent noise-generation from a distinct region in the actual flow. While the methodology worked effectively at conditions considered earlier, recent examination of acoustic data at some unconventional conditions indicate that further improvements are necessary in order to expand the range of applicability of the model. The present work demonstrates how these predictions compare with experimental data gathered by NASA and industry for the purpose of examining the aerodynamic and acoustic performance of such nozzles for a wide range of core and fan stream conditions. Of particular interest are jets with inverted velocity and temperature profiles and the appearance of a second spectral peak at small aft angles to the jet under such conditions. It is shown that a four-component spectrum succeeds in modeling the second peak when the aft angle refraction effects are properly incorporated into the model. A tradeoff of noise emission takes place between two turbulent regions identified as transition and fully mixed regions as the fan stream velocity exceeds that of the core stream. The effect of nozzle discharge coefficients will also be discussed.

  5. Experimental observations of a complex, supersonic nozzle concept

    Science.gov (United States)

    Magstadt, Andrew; Berry, Matthew; Glauser, Mark; Ruscher, Christopher; Gogineni, Sivaram; Kiel, Barry; Skytop Turbulence Labs, Syracuse University Team; Spectral Energies, LLC. Team; Air Force Research Laboratory Team

    2015-11-01

    A complex nozzle concept, which fuses multiple canonical flows together, has been experimentally investigated via pressure, schlieren and PIV in the anechoic chamber at Syracuse University. Motivated by future engine designs of high-performance aircraft, the rectangular, supersonic jet under investigation has a single plane of symmetry, an additional shear layer (referred to as a wall jet) and an aft deck representative of airframe integration. Operating near a Reynolds number of 3 ×106 , the nozzle architecture creates an intricate flow field comprised of high turbulence levels, shocks, shear & boundary layers, and powerful corner vortices. Current data suggest that the wall jet, which is an order of magnitude less energetic than the core, has significant control authority over the acoustic power through some non-linear process. As sound is a direct product of turbulence, experimental and analytical efforts further explore this interesting phenomenon associated with the turbulent flow. The authors acknowledge the funding source, a SBIR Phase II project with Spectral Energies, LLC. and AFRL turbine engine branch under the direction of Dr. Barry Kiel.

  6. Performance modelling of plasma microthruster nozzles in vacuum

    Science.gov (United States)

    Ho, Teck Seng; Charles, Christine; Boswell, Rod

    2018-05-01

    Computational fluid dynamics and plasma simulations of three geometrical variations of the Pocket Rocket radiofrequency plasma electrothermal microthruster are conducted, comparing pulsed plasma to steady state cold gas operation. While numerical limitations prevent plasma modelling in a vacuum environment, results may be obtained by extrapolating from plasma simulations performed in a pressurised environment, using the performance delta from cold gas simulations performed in both environments. Slip regime boundary layer effects are significant at these operating conditions. The present investigation targets a power budget of ˜10 W for applications on CubeSats. During plasma operation, the thrust force increases by ˜30% with a power efficiency of ˜30 μNW-1. These performance metrics represent instantaneous or pulsed operation and will increase over time as the discharge chamber attains thermal equilibrium with the heated propellant. Additionally, the sculpted nozzle geometry achieves plasma confinement facilitated by the formation of a plasma sheath at the nozzle throat, and fast recombination ensures a neutral exhaust plume that avoids the contamination of solar panels and interference with externally mounted instruments.

  7. Study of a flapper-nozzle system for a water hydraulic servovalve; Suiatsu survo ben ni mochiiru nozzle flapper kei no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Urata, E.; Nakao, Y. [Kanagawa University, Kanagawa (Japan). Faculty of Engineering

    1997-06-25

    The paper discusses the characteristics of a flapper-nozzle system for water hydraulic servovalves. High pressure water at the supply port is first used as the working fluid for the hydrostatic bearings supporting the spool. Spool valve stiction induced by poor lubrication with water is thus avoided. The fluid is then led to the ends of the spool and is used as the working fllid of the flapper-nozzle system. In the new flapper-nozzle system the circumferential clearance of the spool becomes a laminar restriction that substitutes fixed orifice used in conventional servovalves. The linearity in the pressure-displacement relationship of the new flapper-nozzle system is better than that of conventional fixed orifice systems. 7 refs., 11 figs., 2 tabs.

  8. Numerical and experimental study of liquid breakup process in solid rocket motor nozzle

    Science.gov (United States)

    Yen, Yi-Hsin

    Rocket propulsion is an important travel method for space exploration and national defense, rockets needs to be able to withstand wide range of operation environment and also stable and precise enough to carry sophisticated payload into orbit, those engineering requirement makes rocket becomes one of the state of the art industry. The rocket family have been classified into two major group of liquid and solid rocket based on the fuel phase of liquid or solid state. The solid rocket has the advantages of simple working mechanism, less maintenance and preparing procedure and higher storage safety, those characters of solid rocket make it becomes popular in aerospace industry. Aluminum based propellant is widely used in solid rocket motor (SRM) industry due to its avalibility, combusion performance and economical fuel option, however after aluminum react with oxidant of amonimum perchrate (AP), it will generate liquid phase alumina (Al2O3) as product in high temperature (2,700˜3,000 K) combustion chamber enviornment. The liquid phase alumina particles aggromorate inside combustion chamber into larger particle which becomes major erosion calprit on inner nozzle wall while alumina aggromorates impinge on the nozzle wall surface. The erosion mechanism result nozzle throat material removal, increase the performance optimized throat diameter and reduce nozzle exit to throat area ratio which leads to the reduction of exhaust gas velocity, Mach number and lower the propulsion thrust force. The approach to avoid particle erosion phenomenon taking place in SRM's nozzle is to reduce the alumina particle size inside combustion chamber which could be done by further breakup of the alumina droplet size in SRM's combustion chamber. The study of liquid breakup mechanism is an important means to smaller combustion chamber alumina droplet size and mitigate the erosion tack place on rocket nozzle region. In this study, a straight two phase air-water flow channel experiment is set up

  9. Variable-density groundwater flow simulations and particle tracking. Numerical modelling using DarcyTools. Preliminary site description of the Simpevarp area, version 1.1

    Energy Technology Data Exchange (ETDEWEB)

    Follin, Sven [SF GeoLogic AB, Stockholm (Sweden); Stigsson, Martin; Berglund, Sten [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Svensson, Urban [Computer-aided Fluid Engineering AB, Norrkoeping (Sweden)

    2004-12-01

    SKB is conducting site investigations for a high-level nuclear waste repository in fractured crystalline rocks at two coastal areas in Sweden, Forsmark and Simpevarp. The investigations started in 2002 and have been planned since the late 1990s. The work presented here investigates the possibility of using hydrogeochemical measurements in deep boreholes to reduce parameter uncertainty in a regional modelling of groundwater flow in fractured rock. The work was conducted with the aim of improving the palaeohydrogeological understanding of the Simpevarp area and to give recommendations to the preparations of the next version of the Preliminary Site Description (1.2). The study is based on a large number of numerical simulations of transient variable density groundwater flow through a strongly heterogeneous and anisotropic medium. The simulations were conducted with the computer code DarcyTools, the development of which has been funded by SKB. DarcyTools is a flexible porous media code specifically designed to treat groundwater flow and salt transport in sparsely fractured crystalline rock and it is noted that some of the features presented in this report are still under development or subjected to testing and verification. The simulations reveal the sensitivity of the results to different hydrogeological modelling assumptions, e.g. the sensitivity to the initial groundwater conditions at 10,000 BC, the size of the model domain and boundary conditions, and the hydraulic properties of deterministically and stochastically modelled deformation zones. The outcome of these simulations was compared with measured salinities and calculated relative proportions of different water types (mixing proportions) from measurements in two deep core drilled boreholes in the Laxemar subarea. In addition to the flow simulations, the statistics of flow related transport parameters were calculated for particle flowpaths from repository depth to ground surface for two subareas within the

  10. Variable-density groundwater flow simulations and particle tracking. Numerical modelling using DarcyTools. Preliminary site description of the Simpevarp area, version 1.1

    International Nuclear Information System (INIS)

    Follin, Sven; Stigsson, Martin; Berglund, Sten; Svensson, Urban

    2004-12-01

    SKB is conducting site investigations for a high-level nuclear waste repository in fractured crystalline rocks at two coastal areas in Sweden, Forsmark and Simpevarp. The investigations started in 2002 and have been planned since the late 1990s. The work presented here investigates the possibility of using hydrogeochemical measurements in deep boreholes to reduce parameter uncertainty in a regional modelling of groundwater flow in fractured rock. The work was conducted with the aim of improving the palaeohydrogeological understanding of the Simpevarp area and to give recommendations to the preparations of the next version of the Preliminary Site Description (1.2). The study is based on a large number of numerical simulations of transient variable density groundwater flow through a strongly heterogeneous and anisotropic medium. The simulations were conducted with the computer code DarcyTools, the development of which has been funded by SKB. DarcyTools is a flexible porous media code specifically designed to treat groundwater flow and salt transport in sparsely fractured crystalline rock and it is noted that some of the features presented in this report are still under development or subjected to testing and verification. The simulations reveal the sensitivity of the results to different hydrogeological modelling assumptions, e.g. the sensitivity to the initial groundwater conditions at 10,000 BC, the size of the model domain and boundary conditions, and the hydraulic properties of deterministically and stochastically modelled deformation zones. The outcome of these simulations was compared with measured salinities and calculated relative proportions of different water types (mixing proportions) from measurements in two deep core drilled boreholes in the Laxemar subarea. In addition to the flow simulations, the statistics of flow related transport parameters were calculated for particle flowpaths from repository depth to ground surface for two subareas within the

  11. Hybrid two fuel system nozzle with a bypass connecting the two fuel systems

    Science.gov (United States)

    Varatharajan, Balachandar [Cincinnati, OH; Ziminsky, Willy Steve [Simpsonville, SC; Yilmaz, Ertan [Albany, NY; Lacy, Benjamin [Greer, SC; Zuo, Baifang [Simpsonville, SC; York, William David [Greer, SC

    2012-05-29

    A hybrid fuel combustion nozzle for use with natural gas, syngas, or other types of fuels. The hybrid fuel combustion nozzle may include a natural gas system with a number of swozzle vanes and a syngas system with a number of co-annular fuel tubes.

  12. Pressure Distribution and Performance Impacts of Aerospike Nozzles on Rotating Detonation Engines

    Science.gov (United States)

    2017-06-01

    Nozzle Exit Plane at Various Pressure Ratios for the Quiescent Air Hydrogen Fuel Case, PRdesign = 10:1...81 Figure 55. Mach Number Distribution along the Nozzle Exit Plane at Various Pressure Ratios for the Supersonic...budget constraints, have spurred engineers to focus on improving the specific fuel consumption of these engines. One technology that promises

  13. Modified computation of the nozzle damping coefficient in solid rocket motors

    Science.gov (United States)

    Liu, Peijin; Wang, Muxin; Yang, Wenjing; Gupta, Vikrant; Guan, Yu; Li, Larry K. B.

    2018-02-01

    In solid rocket motors, the bulk advection of acoustic energy out of the nozzle constitutes a significant source of damping and can thus influence the thermoacoustic stability of the system. In this paper, we propose and test a modified version of a historically accepted method of calculating the nozzle damping coefficient. Building on previous work, we separate the nozzle from the combustor, but compute the acoustic admittance at the nozzle entry using the linearized Euler equations (LEEs) rather than with short nozzle theory. We compute the combustor's acoustic modes also with the LEEs, taking the nozzle admittance as the boundary condition at the combustor exit while accounting for the mean flow field in the combustor using an analytical solution to Taylor-Culick flow. We then compute the nozzle damping coefficient via a balance of the unsteady energy flux through the nozzle. Compared with established methods, the proposed method offers competitive accuracy at reduced computational costs, helping to improve predictions of thermoacoustic instability in solid rocket motors.

  14. 49 CFR 179.100-12 - Manway nozzle, cover and protective housing.

    Science.gov (United States)

    2010-10-01

    ... listed in § 179.101. Manway cover shall be attached to manway nozzle by through or stud bolts not... twenty 3/4-inch studs. The shearing value of the bolts attaching protective housing to manway cover must not exceed 70 percent of the shearing value of bolts attaching manway cover to manway nozzle. Housing...

  15. Dry low NOx combustion system with pre-mixed direct-injection secondary fuel nozzle

    Science.gov (United States)

    Zuo, Baifang; Johnson, Thomas; Ziminsky, Willy; Khan, Abdul

    2013-12-17

    A combustion system includes a first combustion chamber and a second combustion chamber. The second combustion chamber is positioned downstream of the first combustion chamber. The combustion system also includes a pre-mixed, direct-injection secondary fuel nozzle. The pre-mixed, direct-injection secondary fuel nozzle extends through the first combustion chamber into the second combustion chamber.

  16. Nature of convection-stabilized dc arcs in dual-flow nozzle geometry

    International Nuclear Information System (INIS)

    Serbetci, I.; Nagamatsu, H.T.

    1990-01-01

    In this paper, an experimental investigation of the steady-state low-current air arcs in a dual-flow nozzle system is presented. First, the cold flow with no arc as determined for various nozzle geometries, i.e., two- and three-dimensional and orifice nozzles, and nozzle pressure ratios. Supersonic flow separation and oblique and detached shock waves were observed in the flow field. Using a finite-element computer program, the Mach number contours were determined in the flow field for various nozzle-gap spacings and pressure ratios. In addition, the dc arc voltage and current measurements were made for an electrode gap spacing of ∼ 5.5 cm and current levels of I ∼ 25, 50, and 100 A for the three nozzle geometries. The arc voltage and arc power increased rapidly as the flow speed increased from zero to sonic velocity at the nozzle throat. The shock waves in the converging-diverging nozzles resulted in a decrease in the overall resistance by about 15 percent

  17. Leaf area index estimation in a pine plantation with LAI-2000 under direct sunlight conditions: relationship with inventory and hydrologic variables; Estimacion del indice de area foliar en pinares de repolacion con LAI-2000 bajo radiacion solar directa: relacion con variables de inventario e hidrologicas

    Energy Technology Data Exchange (ETDEWEB)

    Molina, A.; Campo, A. D. del

    2011-07-01

    LAI is a key factor in light and rainfall interception processes in forest stands and, for this reason, is called to play an important role in global change adaptive silviculture. Therefore, it is necessary to develop practical and operative methodologies to measure this parameter as well as simple relationships with other silviculture variables. This work has studied 1) the feasibility of LAI-2000 sensor in estimating LAI-stand when readings are taken under direct sunlight conditions; and 2) the ability of LAI in studying rainfall partitioned into throughfall (T) in an Aleppo pine stand after different thinning intensities, as well as its relationships to basal area, (G), cover (FCC), and tree density (D). Results showed that the angular correction scheme applied to LAI-2000 direct-sunlight readings stabilized them for different solar angles, allowing a better operational use of LAI-2000 in Mediterranean areas, where uniform overcast conditions are difficult to meet and predict. Forest cover showed the highest predictive ability of LAI (R{sup 2} = 0.98; S = 0.28), then G (R{sup 2} = 0.96; S = 0.43) and D (R{sup 2} = 0.50; S = 0.28). In the hydrological plane, T increased with thinning intensity, being G the most explanatory variable (R{sup 2} = 0.81; S = 3.07) and LAI the one that showed the poorest relation with it (R{sup 2} = 0.69; S = 3.95). These results open a way for forest hydrologic modeling taking LAI as an input variable either estimated form LAI-2000 or deducted from inventory data. (Author) 36 refs.

  18. Experimental evaluation of ammonia adiabatic absorption into ammonia–lithium nitrate solution using a fog jet nozzle

    International Nuclear Information System (INIS)

    Zacarías, Alejandro; Venegas, María; Lecuona, Antonio; Ventas, Rubén

    2013-01-01

    This paper presents the experimental assessment of the adiabatic absorption of ammonia vapour into an ammonia–lithium nitrate solution using a fog jet nozzle. The ammonia mass fraction was kept constant at 46.08% and the absorber pressure was varied in the range 355–411 kPa. The nozzle was located at the top of the absorption chamber, at a height of 205 mm measured from the bottom surface. The diluted solution flow rate was modified between 0.04 and 0.08 kg s −1 and the solution inlet temperature in the range 25.9–30.2 °C. The influence of these variables on the approach to adiabatic equilibrium factor, outlet subcooling, absorption ratio and mass transfer coefficient is analysed. The approach to adiabatic equilibrium factor for the conditions essayed is always between 0.82 and 0.93. Pressure drop of the solution entering the absorption chamber is also evaluated. Correlations for the approach to adiabatic equilibrium factor and the Sherwood number are given. - Highlights: ► Adiabatic absorption of NH 3 vapour into NH 3 –LiNO 3 using fog jet nozzle created spray. ► Pressure drop of the solution entering to the absorption chamber is evaluated. ► Approach to adiabatic equilibrium factor (F) is between 0.82 and 0.93 at 205 mm height. ► Experimental values of mass transfer coefficient and outlet subcooling are presented. ► Correlations for F and Sherwood number are given.

  19. Experimental assessment of ammonia adiabatic absorption into ammonia-lithium nitrate solution using a flat fan nozzle

    International Nuclear Information System (INIS)

    Zacarias, A.; Venegas, M.; Ventas, R.; Lecuona, A.

    2011-01-01

    This paper presents the experimental evaluation of the adiabatic absorption of ammonia vapour into ammonia-lithium nitrate solution using a flat fan nozzle and an upstream single-pass subcooler. Data are representative of the working conditions of adiabatic absorbers in absorption chillers. The nozzle was located at the top of the absorption chamber, separated 205 mm from the bottom surface. The diluted solution mass flow rate was modified between 0.04 and 0.08 kg/s and the solution inlet temperature between 24.5 and 29.7 o C. The influence of these variables on the absorption ratio, mass transfer coefficient, outlet subcooling and approach to equilibrium factor is analysed in the present paper. A linear relation between the inlet subcooling and the absorption ratio is observed. The approach to equilibrium factor for the conditions essayed is always between 0.81 and 0.89. Mass transfer coefficients and correlations for the approach to equilibrium factor and the Sherwood number are obtained. Results are compared with other ones reported in the literature. - Highlights: → Adiabatic absorption of NH 3 vapour into NH 3 -LiNO 3 using flat fan nozzle created spray. → A linear relation exists between solution inlet subcooling and absorption ratio. → The approach to equilibrium factor is always between 0.81 and 0.89 at 205 mm height. → Experimental values of mass transfer coefficient and outlet subcooling are presented. → Correlations for the approach to equilibrium factor and the Sherwood number are given.

  20. Design and testing of low-divergence elliptical-jet nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Rouly, Etienne; Warkentin, Andrew; Bauer, Robert [Dalhousie University, Halifax (China)

    2015-05-15

    A novel approach was developed to design and fabricate nozzles to produce high-pressure low-divergence fluid jets. Rapid-prototype fabrication allowed for myriad experiments investigating effects of different geometric characteristics of nozzle internal geometry on jet divergence angle and fluid distribution. Nozzle apertures were elliptical in shape with aspect ratios between 1.00 and 2.45. The resulting nozzle designs were tested and the lowest elliptical jet divergence angle was 0.4 degrees. Nozzle pressures and flowrates ranged from 0.32 to 4.45 MPa and 13.6 to 37.9 LPM, respectively. CimCool CimTech 310 machining fluid was used in all experiments at a Brix concentration of 6.6 percent.