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Sample records for orifice nozzle applied

  1. Flow-throttling orifice nozzle

    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.)

  2. 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

    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.

  3. High Pressure Water Stripping Using Multi-Orifice Nozzles

    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

  4. Multi-orifice deposition nozzle for additive manufacturing

    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.

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

    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

  6. Method for generating small and ultra small apertures, slits, nozzles and orifices

    Khounsary, Ali M [Hinsdale, IL

    2012-05-22

    A method and device for one or more small apertures, slits, nozzles and orifices, preferably having a high aspect ratio. In one embodiment, one or more alternating layers of sacrificial layers and blocking layers are deposited onto a substrate. Each sacrificial layer is made of a material which preferably allows a radiation to substantially pass through. Each blocking layer is made of a material which substantially blocks the radiation.

  7. Effect of Orifice Nozzle Design and Input Power on Two-Phase Flow and Mass Transfer Characteristics

    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.

  8. Design and analysis of throttle orifice applying to small space with large pressure drop

    Li Yan; Lu Daogang; Zeng Xiaokang

    2013-01-01

    Throttle orifices are widely used in various pipe systems of nuclear power plants. Improper placement of orifices would aggravate the vibration of the pipe with strong noise, damaging the structure of the pipe and the completeness of the system. In this paper, effects of orifice diameter, thickness, eccentric distance and chamfering on the throttling are analyzed applying CFD software. Based on that, we propose the throttle orifices which apply to small space with large pressure drop are multiple eccentric orifices. The results show that the multiple eccentric orifices can effectively restrain the cavitation and flash distillation, while generating a large pressure drop. (authors)

  9. Numerical Simulation of Twin Nozzle Injectors

    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...

  10. Multiple-Nozzle Spray Head Applies Foam Insulation

    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.

  11. Development of technique to apply induction heating stress improvement to recirculation inlet nozzle

    Chiba, Kunihiko; Nihei, Kenichi; Ootaka, Minoru

    2009-01-01

    Stress corrosion cracking (SCC) have been found in the primary loop recirculation (PLR) systems of boiling water reactors (BWR). Residual stress in welding heat-affected zone is one of the factors of SCC, and the residual stress improvement is one of the most effective methods to prevent SCC. Induction heating stress improvement (IHSI) is one of the techniques to improve reduce residual stress. However, it is difficult to apply IHSI to the place such as the recirculation inlet nozzle where the flow stagnates. In this present study, the technique to apply IHSI to the recirculation inlet nozzle was developed using water jet which blowed into the crevice between the nozzle safe end and the thermal sleeve. (author)

  12. Fabrication of small-orifice fuel injectors for diesel engines.

    Woodford, J. B.; Fenske, G. R.

    2005-04-08

    Diesel fuel injector nozzles with spray hole diameters of 50-75 {micro}m have been fabricated via electroless nickel plating of conventionally made nozzles. Thick layers of nickel are deposited onto the orifice interior surfaces, reducing the diameter from {approx}200 {micro}m to the target diameter. The nickel plate is hard, smooth, and adherent, and covers the orifice interior surfaces uniformly.

  13. Focusing liquid microjets with nozzles

    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)

  14. Nozzle geometry variations on the discharge coefficient

    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.

  15. External Cylindrical Nozzle with Controlled Vacuum

    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

  16. Numerical evaluation of weld overlay applied to a pressurized water reactor nozzle mock-up

    Rabello, Emerson G.; Silva, Luiz L.; Gomes, Paulo T.V., E-mail: egr@cdtn.b, E-mail: silvall@cdtn.b, E-mail: gomespt@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Integridade Estrutural

    2011-07-01

    The primary water stress corrosion cracking (PWSCC) is a major mechanism of failure in the primary circuit of PWR type nuclear power plants. The PWSCC is associated with the presence of corrosive environment, the susceptibility to corrosion cracking of the materials involved and the tensile stresses presence. Residual stresses generated during dissimilar materials welding can contribute to PWSCC. An alternative to the PWSCC mitigation is the application of external weld layers in the regions of greatest susceptibility to corrosion cracking. This process, called Weld Overlay (WOL), has been widely used in regions of dissimilar weld (low alloy steel and stainless steel with nickel alloy addition) of nozzles and pipes on the primary circuit in order to promote internal compressive stresses on the wall of these components. This paper presents the steps required to the numerical stress evaluation (by finite element method) during the dissimilar materials welding as well as application of Weld Overlay process in a nozzle mock-up. Thus, one can evaluate the effectiveness of the application of weld overlay process to internal compressive stress generation on the wall nozzle. (author)

  17. Numerical evaluation of weld overlay applied to a pressurized water reactor nozzle mock-up

    Rabello, Emerson G.; Silva, Luiz L.; Gomes, Paulo T.V.

    2011-01-01

    The primary water stress corrosion cracking (PWSCC) is a major mechanism of failure in the primary circuit of PWR type nuclear power plants. The PWSCC is associated with the presence of corrosive environment, the susceptibility to corrosion cracking of the materials involved and the tensile stresses presence. Residual stresses generated during dissimilar materials welding can contribute to PWSCC. An alternative to the PWSCC mitigation is the application of external weld layers in the regions of greatest susceptibility to corrosion cracking. This process, called Weld Overlay (WOL), has been widely used in regions of dissimilar weld (low alloy steel and stainless steel with nickel alloy addition) of nozzles and pipes on the primary circuit in order to promote internal compressive stresses on the wall of these components. This paper presents the steps required to the numerical stress evaluation (by finite element method) during the dissimilar materials welding as well as application of Weld Overlay process in a nozzle mock-up. Thus, one can evaluate the effectiveness of the application of weld overlay process to internal compressive stress generation on the wall nozzle. (author)

  18. Process for manufacturing separating nozzles

    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

  19. Motion of a single quantized vortex in an orifice

    Schwarz, K.W.

    1993-01-01

    Discrete phase-slip events are observed when superfluid 4 He moves through a microscopic orifice. In order to understand such behavior, one must know (a) how a quantized vortex is introduced into the orifice, and (b) how such a vortex evolves fluid dynamically so as to absorb energy from the applied flow field. To begin the study of the latter question, the authors present calculations done with an idealized orifice geometry. It is found that vortex loops larger than a critical size are carried out of the orifice and stretched by the diverging flow. As it stretches, such a vortex will cross the orifice, the energy required to stretch the vortex being absorbed from the flow field. Both a vortex loop introduced directly into the orifice and a remanent vortex extending to infinity will be discussed

  20. Analysis of the combined effect of hydrogrinding process and inclination angle on hydraulic performance of diesel injection nozzles

    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

  1. Periodic cavitation shedding in a cylindrical orifice

    Stanley, C.; Barber, T.; Milton, B.; Rosengarten, G. [University of New South Wales, School of Mechanical and Manufacturing Engineering, Sydney (Australia)

    2011-11-15

    Cavitation structures in a large-scale (D = 8.25 mm), plain orifice style nozzle within a unique experimental rig are investigated using high-speed visualisation and digital image processing techniques. Refractive index matching with an acrylic nozzle is achieved using aqueous sodium iodide for the test fluid. Cavitation collapse length, unsteady shedding frequency and spray angles are measured for cavitation conditions from incipient to supercavitation for a range of Reynolds numbers, for a fixed L/D ratio of 4.85. Periodic cavitation shedding was shown to occur with frequencies between 500 and 2,000 Hz for conditions in which cavitation occupied less than 30% of the nozzle length. A discontinuity in collapse length was shown to occur once the cavitation exceeded this length, coinciding with a loss of periodic shedding. A mechanism for this behaviour is discussed. Peak spray angles of approximately {theta} {approx} 14 were recorded for supercavitation conditions indicating the positive influence of cavitation bubble collapse on the jet atomisation process. (orig.)

  2. Influence of Water-jet Nozzle Geometry on Cutting Ability of Soft Material

    Irwansyah Irwansyah

    2012-06-01

    Full Text Available Hygiene is main reason for food processor to use waterjet cutting system. Traditionally food cutting process is low-quality, unsafe products, procedures and direct contact between product and labor. This paper introduced a low cost waterjet system for cutting soft material as identic food material. The low cost waterjet system has been developed by using a commercial pressure pump for cleaning purposes and modified nozzle. In order to enhance waterjet pressure for cutting products, a modified waterjet nozzle was designed. Paramater design of waterjet system was setup on nozzle orifice diameter 0.5 mm, standoff distance 15 mm, length of nozzle cylindrical tube 2.5 mm. Polycarbonate, polysterene, and polyethelene materials are used as sample product with thickness 2 mm, to represent similar properties with agriculture products. The experimental results indicate good possibilities of waterjet system to cut material in appropriate profile surface. The waterjet also can be used to improve cutting finished surface of food products. Therefore, utilizing a low cost commercial pump and modified nozzle for waterjet system reduces equipment price, operational cost and environmental hazards. It indicates viable technology applied to substitute traditional cutting technology in post harvest agriculture products. Keywords: cutting ability, modified nozzle, polymer material, water-jet system

  3. A preliminary investigation of the design parameters of an air induction nozzle

    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.

  4. Microalgal cell disruption via ultrasonic nozzle spraying.

    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.

  5. Nozzle seal

    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

  6. Nozzle seal

    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

  7. Cold water injection nozzles

    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.)

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

    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.

  9. The penetration of aerosols through fine orifices

    Marshall, I.A.; Latham, L.J.; Ball, M.H.E.; Mitchell, J.P.

    1991-07-01

    A novel experimental technique has been extended to study the migration of gas-borne glass microspheres in the size range from about 1 to 15 μm volume equivalent diameter through orifices with bores and thicknesses in the range from 2 to 100 μm and 12.7 to 509 μm respectively. The penetration of these particles was significant with all orifices greater than 10 μm bore at a constant driving pressure of 100 kPa. However, few particles penetrated the 5 μm bore orifice, while virtually no particles penetrated the 2 μm bore orifice. Particle size distributions determined after penetration through the orifices were very similar to that of the upstream aerosol except when significant attenuation occurred. (author)

  10. Fuel nozzle assembly

    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.

  11. Limit loads in nozzles

    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

  12. Study of a flapper-nozzle system for a water hydraulic servovalve; Suiatsu survo ben ni mochiiru nozzle flapper kei no kenkyu

    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.

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

    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

  14. Nozzle airfoil having movable nozzle ribs

    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.

  15. Quantitative characterization of near-field fuel sprays by multi-orifice direct injection using ultrafast x-tomography technique

    Liu, X.; Im, K.S.; Wang, Y.; Wang, J.; Hung, D.L.S.; Winkelman, J.R.; Tate, M.W.; Ercan, A.; Koerner, L.J.; Caswell, T.; Chamberlain, D.; Schuette, D.R.; Philipp, H.; Smilgies, D.M.; Gruner, S.M.

    2006-01-01

    A low-pressure direct injection fuel system for spark ignition direct injection engines has been developed, in which a high-turbulence nozzle technology was employed to achieve fine fuel droplet size at a low injection pressure around 2 MPa. It is particularly important to study spray characteristics in the near-nozzle region due to the immediate liquid breakup at the nozzle exit. By using an ultrafast x-ray area detector and intense synchrotron x-ray beams, the interior structure and dynamics of the direct injection gasoline sprays from a multi-orifice turbulence-assisted nozzle were elucidated for the first time in a highly quantitative manner with μs-temporal resolution. Revealed by a newly developed, ultrafast computed x-microtomography technique, many detailed features associated with the transient liquid flows are readily observable in the reconstructed spray. Furthermore, an accurate 3-dimensional fuel density distribution, in the form of fuel volume fraction, was obtained by the time-resolved computed tomography. The time-dependent fuel density distribution revealed that the fuel jet is well broken up immediately at the nozzle exits. These results not only reveal the near-field characteristics of the partial atomized fuel sprays with unprecedented detail, but also facilitate the development of an advanced multi-orifice direct injector. This ultrafast tomography capability also will facilitate the realistic computational fluid dynamic simulations in highly transient and multiphase fuel spray systems.

  16. Fractal analysis of agricultural nozzles spray

    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.

  17. Cold spray nozzle design

    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.

  18. The impact assessment of eccentric installation and roughness change in piping on the orifice flow measurement

    Nishi, Y.; Eguchi, Y.; Nishihara, T.; Kanai, T.; Kondo, M.

    2012-01-01

    In orifice flowmeters used in nuclear power plants, requirements for the inner surface roughness of upstream piping and eccentric installation exist depending on certain standards. If these cannot be satisfied based on the installation condition, an appropriate error margin must be considered, although this remains to be clarified. In this research, quantitative data concerning the relative error of orifice flowmeters were obtained during experiments with the parameters of the inner surface roughness of upstream piping and the installation eccentricity of the orifice hole. The maximum Reynolds number of the experimental facility is about 1.6x10 6 . In orifice flowmeters, the flow rate is calculated based on the differential pressure between upstream and downstream orifices and the peculiar discharge coefficient C. The latter value shows an upward trend with increasing roughness of piping, while change of 0.3% of C was observed in terms of roughness (case 2), which approaches the limits of the JIS standard. With significant roughness (Case 3) that exceeds five times the JIS standard, C is shown to have increased by about 1%. No influence was observed by varying the direction of eccentric installation, hence this was fixed and the amount of eccentricity was considered. Change in C of about 0.25% was observed when around twice the standard level of eccentricity was applied. The error margin data under conditions exceeding the JIS standard for the orifice flowmeter was obtained. (authors)

  19. Choked flow mechanism of HFC-134a flowing through short-tube orifices

    Nilpueng, Kitti; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok (Thailand)

    2011-02-15

    This paper is a continuation of the author's previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube orifices under choked flow condition are presented. Short-tube orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a miniature vapour-compression refrigeration system are examined. The experimental results indicated that the occurrence of choked flow phenomena inside short-tube orifices is different from that obtained from short-tube orifice diameters of greater than 1 mm, which are typically used in air-conditioner. The beginning of choked flow is dependent on the downstream pressure, degree of subcooling, and length-to-diameter ratio. Under choked flow condition, the mass flow rate is greatly varied with the short-tube orifice dimension, but it is slightly affected by the operating conditions. A correlation of mass flow rate through short-tube orifices is proposed in terms of the dimensionless parameters. The predicted results show good agreement with experimental data with a mean deviation of 4.69%. (author) transfer coefficient was also proposed. (author)

  20. A Study of System Pressure Transients Generated by Isolation Valve Open/Closure in Orifice Manifold

    Kim, M. [KEPCO, Daejeon (Korea, Republic of); Bae, S. W.; Kim, J. I.; Park, S. J. [KHNP, Abu Dhabi (United Arab Emirates)

    2016-05-15

    In this study, we explore the effects of pressure transients on peak and minimal pressures caused by the actuation of isolation valve and control valve reacting to the combined orifice operation of orifice manifold with motor-operated valve installed in the rear of the orifice. We then use the collected data to direct our effort towards cause analysis and propose improvements to efficiency and safety of operation. This formation is used to by domestic and foreign nuclear power plants as a mean to control flow rate, producing required flow rate jointly together by combination of the orifices. No significant impacts on the internals of manifold orifice due to peak pressure has been observed, although chance of cavitation at the outlet of control valve is significant. Considering the peak pressure, as well as minimum pressure occurs in low flow rate conditions, the pressure transient is more so affected by the characteristics (modified equal percentage) of control valve. Isolation valve of the orifice and control valve operate organically, therefore stroke time for valves need to be applied in order for both valves to cooperatively formulate an optimized operation.

  1. Improvement of combustion in a direct injection diesel engine by micro-hole nozzle; Micro hole nozzle wo mochiita chokusetsu funshashiki diesel kikan no nensho kaizen

    Murata, M. [Keio University, Tokyo (Japan); Kobori, S. [Tokyo Institute of Technology, Tokyo (Japan); Iida, N. [Keio University, Tokyo (Japan). Faculty of Science and Technology

    2000-07-25

    In an attempt to promote the atomization of fuel spray and the mixing of fuel and air in diesel engines, a micro-hole nozzle which has orifices with a diameter smaller than 0.10mm was developed. In this study, the combustion tests were carried out using a single cylinder diesel engine equipped with a micro-hole nozzle and a common rail type high-pressure fuel injection system. A comparison with the results of a conventional nozzle experiment showed that the peak of initial premixed combustion increased, but the peak of diffusion combustion decreased. As a result, when nozzle orifice diameter become small from {phi} 0.15 mm to {phi} 0.10 mm, the combustion was accompanied by smokeless with the same levels of NO{sub x} emission and fuel economy. And results of a comparison the toroidal type chamber with the shallow dish type chamber revealed that the optimization of combustion chamber is necessary for the increase of the injection stage with increasing of the number of nozzle orifice. If an orifice diameter becomes {phi} 0.06 mm, the diffusion combustion can not be observed and the combustion is formed of only premixed combustion. The combustion in the case of {phi} 0.06 mm was accompanied with the drastic deterioration of fuel economy, smoke and HC with all over load. But the micro-hole nozzle has a potential for the formation of the lean and homogeneous premixed mixture until the fuel-air mixture ignites. (author)

  2. Design and fabrication of a PET/PTFE-based piezoelectric squeeze mode drop-on-demand inkjet printhead with interchangeable nozzle

    Li, Erqiang

    2010-09-01

    A PET/PTFE-based piezoelectric squeeze mode drop-on-demand inkjet printhead with interchangeable nozzles is designed and fabricated. The printhead chamber is comprised of PET (polyethylene terephthalate) tubing or PTFE (polytetrafluoroethylene, or Teflon) tubing, which of a much softer material, than the conventionally used glass tubing. Applying the same electrical voltage, PET/PTFE-based printhead will generate a larger volume change in the material to be dispensed. The novel printhead fabricated herein has successfully dispensed liquids with viscosities up to 100 cps, as compared to 20 cps for the commercial printheads. Furthermore, PTFE-based printhead provides excellent anti-corrosive property when strongly corrosive inks are involved. The interchangeable nozzle design enables the same printhead to be fitted with nozzles of different orifice size, thus a clogged nozzle can be easily removed for cleaning or replacement. The characteristics of this novel printhead are also studied by dispensing glycerin-water solutions. © 2010 Elsevier B.V. All rights reserved.

  3. Variable orifice using an iris shutter

    Beeman, R.; Brajkovich, S.J.

    1978-01-01

    A variable orifice forming mechanism is described that utilizes shutter arrangement adapted to control gas flow, conductance in vacuum systems, as a heat shield for furnace windows, as a beam shutter in sputtering operations, and in any other application requiring periodic or continuously-variable control of material, gas, or fluid flow

  4. Sizing of high-pressure restriction orifices

    Casado Flores, E.

    1995-01-01

    Constant up-grading of power plants sometimes requires the modification of components which form part of suppliers' packages. In order to protect technology they have developed, however, the suppliers do not supply their calculation criteria. In order to reduce the costs of such improvements, and so as to be able to undertake the modification without having to rely on the original supplier, this paper describes the basic criteria applicable to the study of high-pressure restriction orifices, which can be considered to be representative of the components in question. The restriction orifices discussed are: - Insert - Multiplates in series with one perforation in each plate - Multiplates in series with several perforations in each plate For each type, an explanation of their sizing is given, together with the equations relating the corresponding flow and pressure drop. (Author)

  5. Experimental investigation of hydrodynamic cavitation through orifices of different geometries

    Rudolf, Pavel; Kubina, Dávid; Hudec, Martin; Kozák, Jiří; Maršálek, Blahoslav; Maršálková, Eliška; Pochylý, František

    Hydrodynamic cavitation in single and multihole orifices was experimentally investigated to assess their hydraulic characteristics: loss coefficients, inception cavitation number, cavitation number for transition to supercavitation. Significant difference for singlehole and multihole orifices was observed in terms of the measured loss coefficient. It is significantly more effective to use multihole orifices, where energy dissipation is much lower.It was found that using scaling factor given by ratio of orifice thickness suggests linear behaviour of both loss coefficient and inception cavitation number. Orifices seem to be convenient choice as flow constriction devices inducing cavitation due to their simplicity.

  6. Experimental investigation of hydrodynamic cavitation through orifices of different geometries

    Rudolf Pavel

    2017-01-01

    Full Text Available Hydrodynamic cavitation in single and multihole orifices was experimentally investigated to assess their hydraulic characteristics: loss coefficients, inception cavitation number, cavitation number for transition to supercavitation. Significant difference for singlehole and multihole orifices was observed in terms of the measured loss coefficient. It is significantly more effective to use multihole orifices, where energy dissipation is much lower.It was found that using scaling factor given by ratio of orifice thickness suggests linear behaviour of both loss coefficient and inception cavitation number. Orifices seem to be convenient choice as flow constriction devices inducing cavitation due to their simplicity.

  7. Altitude Compensating Nozzle

    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.

  8. Advanced exhaust nozzle technology

    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.

  9. Firefighter Nozzle Reaction

    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...

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

    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. Firefighter Nozzle Reaction

    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...

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

    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)

  13. Flow through a cylindrical pipe with a periodic array of fractal orifices

    van Melick, P.A.J.; Geurts, Bernardus J.

    2013-01-01

    We apply direct numerical simulation (DNS) of the incompressible Navier–Stokes equations to predict flow through a cylindrical pipe in which a periodic array of orifice plates with a fractal perimeter is mounted. The flow is simulated using a volume penalization immersed boundary method with which

  14. Flow through a cylindrical pipe with a periodic array of fractal orifices

    van Melick, P.A.J.; Geurts, B.J.

    2013-01-01

    We apply direct numerical simulation (DNS) of the incompressible Navier-Stokes equations to predict flow through a cylindrical pipe in which a periodic array of orifice plates with a fractal perimeter is mounted. The flow is simulated using a volume penalization immersed boundary method with which

  15. Coupled calculation of diesel injection, primary spray propagation and spray formation using a multifluid approach and comparison with experiments in transparent model nozzles; Gekoppelte Berechnung von Dieseleinspritzung, primaerem Strahlzerfall und Spraybildung mit dem Multifluid-Ansatz und Vergleich mit Experimenten in transparenten Modellduesen

    Berg, E. von; Edelbauer, W.; Alajbegovic, A.; Tatschl, R. [AVL List GmbH, Graz (Austria)

    2004-07-01

    Based on the Eulerian multi-fluid approach cavitating nozzle flow in Diesel injectors as well as spray formation downstream of the nozzle orifice can be simulated in a single calculation. Fuel liquid, fuel vapor, spray droplets, and air are treated as interpenetrating phases. For each of the phases separate sets of conservation equations are solved. Different flow regimes such as cavitating nozzle flow and spray regions are described by using appropriate interfacial exchange terms between the phases. Besides a simplified calculation procedure the main advantage of this methodology is the direct coupling of the different flow regimes. Thus, effects of the cavitating nozzle flow can directly enter the primary break-up model, which is based on locally resolved nozzle flow turbulence. This new approach is applied for single- and multi-hole full scale Diesel injectors as well as for a large-scale model injector operated with water. The results obtained on the basis of the CFD code FIRE show good agreement compared to experimental data and yield the correct trends for both spray penetration and spray angle for increasing injection pressure. (orig.)

  16. Gaseous Nitrogen Orifice Mass Flow Calculator

    Ritrivi, Charles

    2013-01-01

    The Gaseous Nitrogen (GN2) Orifice Mass Flow Calculator was used to determine Space Shuttle Orbiter Water Spray Boiler (WSB) GN2 high-pressure tank source depletion rates for various leak scenarios, and the ability of the GN2 consumables to support cooling of Auxiliary Power Unit (APU) lubrication during entry. The data was used to support flight rationale concerning loss of an orbiter APU/hydraulic system and mission work-arounds. The GN2 mass flow-rate calculator standardizes a method for rapid assessment of GN2 mass flow through various orifice sizes for various discharge coefficients, delta pressures, and temperatures. The calculator utilizes a 0.9-lb (0.4 kg) GN2 source regulated to 40 psia (.276 kPa). These parameters correspond to the Space Shuttle WSB GN2 Source and Water Tank Bellows, but can be changed in the spreadsheet to accommodate any system parameters. The calculator can be used to analyze a leak source, leak rate, gas consumables depletion time, and puncture diameter that simulates the measured GN2 system pressure drop.

  17. [Natural Orifice Transluminal Endoscopic Surgery (NOTES)].

    Kim, Yong Sik; Kim, Chul Young; Chun, Hoon Jai

    2008-03-01

    Recently, the field of gastrointestinal endoscopy is developing rapidly. Once limited to the gastroinstestinal lumen, the endoscopic technology is now breaking the barriers and extending its boundary to peritoneal and pleural space. In 2004, Dr. Kalloo, a gastroenterologist, observed intraperitoneal organs of a pig using a conventional endoscope through the stomach wall. Since then, new endoscopic technique of intraperitoneal intervention with transluminal approach named the Natural Orifice Transluminal Endoscopic Surgery or NOTES has been introduced. NOTES reaches the target organ by inserting the endoscope through a natural orifice (e.g. mouth, anus, vagina, urethra) and entering the peritoneal lumen by means of making an incision on the luminal wall. After a series of successful experiences in animal studies, NOTES are now being tried on human subjects. There are still many obstacles to overcome, but bright future for this new technology is expected because of its proposed advantages of less pain, lower complication rate, short recovery time, and scarless access. In this review, we plan to learn about NOTES.

  18. A Mandibular Second Premolar with Three Canals and Atypical Orifices

    Neha Agarwal

    2013-01-01

    Full Text Available Background: Mandibular second premolars with three canals (Type V, Vertucci and separate foramina are very rare. The anatomy of the pulp chamber floor in these premolars usually reveals one lingual and two buccal orifices at the same level. This case report describes a second premolar with three canals and an unusual pulpal floor anatomy with one mesiobuccal and one distobuccal orifice at the same level and an orifice on the distolingual wall. Very careful examination of the pulpal space with an optical device and preoperative spiral computed tomography is recommended to locate any unusual orifices.

  19. 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

    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

  20. Nature of convection-stabilized dc arcs in dual-flow nozzle geometry

    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

  1. Jet flow issuing from an axisymmetric pipe-cavity-orifice nozzle

    Broučková, Zuzana; Pušková, P.; Trávníček, Zdeněk; Šafařík, P.

    2016-01-01

    Roč. 114, March (2016), č. článku 02006. ISSN 2101-6275. [International Conference on Experimental Fluid Mechanics /10./. Praha, 17.11.2015-20.11.2015] R&D Projects: GA ČR GA14-08888S Institutional support: RVO:61388998 Keywords : passive control * acoustic excitations * resonator Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts

  2. Jet flow issuing from an axisymmetric pipe-cavity-orifice nozzle

    Broučková Zuzana

    2016-01-01

    Full Text Available An axisymmetric air jet flow is experimentally investigated under passive flow control. The jet issues from a pipe of the inner diameter and length of 10 mm and 150 mm which is equipped with an axisymmetric cavity at the pipe end. The cavity operates as a resonator creating self-sustained acoustic excitations of the jet flow. A mechanism of excitations is rather complex – in comparison with a common Helmholtz resonator. The experiments were performed using flow visualization, microphone measurements and time-mean velocity measurements by the Pitot probe. The power spectral density (PSD and the sound pressure level (SPL were evaluated from microphone measurements. The jet Reynolds number ranged Re = 1600–18 000. Distinguishable peaks in PSD indicated a function of the resonator. Because the most effective acoustic response was found at higher Re, a majority of experiments focused on higher Re regime. The results demonstrate effects of the passive control on the jet behavior. Fluid mixing and velocity decay along the axis is intensified. It causes shortening of the jet transition region. On the other hand, an inverse proportionality of the velocity decay (u ~ 1/x in the fully developed region is not changed. The momentum and kinetic energy fluxes decrease more intensively in the controlled jets in comparison with common jets.

  3. Mass transfer coefficient in disturbed flow due to orifice for flow accelerated corrosion in nuclear power plant

    Prasad, Mahendra; Gaikwad, Avinash J.; Sridharan, Arunkumar; Parida, Smrutiranjan

    2015-01-01

    The flow of fluid in pipes cause corrosion wherein the inner surface of pipe becomes progressively thinner and susceptible to failure. This form of corrosion dependent on flow dynamics is called Flow Accelerated Corrosion (FAC) and has been observed in Nuclear Power Plants (NPPs). Mass transfer coefficient (MTC) is related to extent of wall thinning and it changes from its value in a straight pipe (with same fluid parameters) for flow in orifices, bends, junctions etc. due to gross disturbance of the velocity profile. This paper presents two-dimensional computational fluid dynamics (CFD) simulations for an orifice configuration in a straight pipe. Turbulent model K- ω with shear stress transport and transition flow was the model used for simulation studies. The mass transfer boundary layer (MTBL) thickness δ mtbl is related to the Schmidt number (Sc) and hydrodynamic boundary layer thickness δ h , as δ mtbl ~ δh/(Sc 1/3 ). MTBL is significantly smaller than δ h and hence boundary layer meshing was carried out deep into δ mtbl . Uniform velocity profile was applied at the inlet. Post orifice fluid shows large recirculating flows on the upper and lower wall. At various locations after orifice, mass transfer coefficient is calculated and compared with the value in straight pipe with fully developed turbulent flow. The MTC due to the orifice increases and it is correlated with enhanced FAC in region after orifice. (author)

  4. SHINE Tritium Nozzle Design: Activity 6, Task 1 Report

    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.

  5. The characterisation of diesel nozzle flow using high speed imaging of elastic light scattering

    Lockett, R. D.; Liverani, L.; Thaker, D.; Jeshani, M.; Tait, N. P.

    2013-01-01

    Two identical, conventional six-hole, valve-covered orifice (VCO) diesel injectors have been modified in order to provide optical access to the region below the needle, and the nozzle-flow passages. This has been achieved through the removal of the metal tips, and their replacement with transparent acrylic tips of identical geometry. \\ud \\ud These two identical injectors were employed in order to offer comparability between the measurements. One of them had a dark, anodised inner surface at t...

  6. Minimum wall pressure coefficient of orifice plate energy dissipater

    Wan-zheng Ai

    2015-01-01

    Full Text Available Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  7. Orifice design for the control of coupled region flow

    Atherton, R.; Spadaro, P.R.; Brummerhop, F.G.

    1975-01-01

    A fluid system arrangement for nuclear reactors is described comprising a triplate orifice apparatus which simultaneously controls core flow distribution, flow rate ratio between hydraulically coupled regions of the blanket and radial static pressure gradients entering and leaving the blanket fuel region. The design of the apparatus is based on the parameters of the diameter of the orifice holes, the friction factor, and expansion, contraction and turning pressure loss coefficients of the geometry of each orifice region. These above parameters are properly matched to provide the desired pressure drop, flow split and negligible cross flow at the interface of standard and power-flattened open lattice blanket regions. (U.S.)

  8. Pressure atomizer having multiple orifices and turbulent generation feature

    VanBrocklin, Paul G.; Geiger, Gail E.; Moran, Donald James; Fournier, Stephane

    2002-01-01

    A pressure atomizer includes a silicon plate having a top surface and a bottom surface. A portion of the top surface defines a turbulent chamber. The turbulent chamber is peripherally bounded by the top surface of the plate. The turbulent chamber is recessed a predetermined depth relative to the top surface. The silicon plate further defines at least one flow orifice. Each flow orifice extends from the bottom surface of the silicon plate to intersect with and open into the turbulent chamber. Each flow orifice is in fluid communication with the turbulent chamber.

  9. Model based decision support system of operating settings for MMAT nozzles

    Fritz Bradley Keith

    2016-04-01

    Full Text Available Droplet size, which is affected by nozzle type, nozzle setups and operation, and spray solution, is one of the most critical factors influencing spray performance, environment pollution, food safety, and must be considered as part of any application scenario. Characterizing spray nozzles can be a timely and expensive proposition if the entire operational space (all combinations of spray pressure and orifice size, what influence flow rate is to be evaluated. This research proposes a structured, experimental design that allows for the development of computational models for droplet size based on any combination of a nozzle’s potential operational settings. The developed droplet size determination model can be used as Decision Support System (DSS for precise selection of sprayer working parameters to adapt to local field scenarios. Five nozzle types (designs were evaluated across their complete range of orifice size (flow rate* and spray pressures using a response surface experimental design. Several of the models showed high level fits of the modeled to the measured data while several did not as a result of the lack of significant effect from either orifice size (flow rate* or spray pressure. The computational models were integrated into a spreadsheet based user interface for ease of use. The proposed experimental design provides for efficient nozzle evaluations and development of computational models that allow for the determination of droplet size spectrum and spraying classification for any combination of a given nozzle’s operating settings. The proposed DSS will allow for the ready assessment and modification of a sprayers performance based on the operational settings, to ensure the application is made following recommendations in plant protection products (PPP labels.

  10. Characterisation of subsonic axisymmetric nozzles

    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

  11. Duplex tab exhaust nozzle

    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.

  12. Evaluation of RF properties by orifice design for IFMIF RFQ

    Maebara, Sunao; Sugimoto, Masayoshi

    2005-03-01

    Orifices for the IFMIF RFQ have been designed and fabricated, and RF properties have been evaluated by a network analyzer. The designed orifices were installed into a vacuum port of the 1.1m-long RFQ mock-up module, and the resonant frequency and the phase difference between cavities were measured for a quadrupole operation mode of TE 210 . It was found that the RF properties are not affected on condition that slit direction with the same direction of current flow at the RFQ wall. Orifice conductance from 0.22 to 0.25 m 3 /sec by nitrogen conversion at room temperature was designed, and an ultimate pressure level of 5x10 -7 [Pa] was evaluated for the 4.1m-long central module for the IFMIF RFQ. It was concluded that the designed orifices are effective for RF properties and vacuum conductance in the IFMIF RFQ. (author)

  13. Investigation of wall mass transfer characteristics downstream of an orifice

    El-Gammal, M.; Ahmed, W.H.; Ching, C.Y.

    2012-01-01

    Highlights: ► Numerical simulations were performed for the mass transfer downstream of an orifice. ► The Low Reynolds Number K-ε turbulence model was used. ► The numerical results were in good agreement with existing experimental results. ► The maximum Sherwood number downstream of the orifice was significantly affected by the Reynolds number. ► The Sherwood number profile was well correlated with the turbulence kinetic energy profile close to the wall. - Abstract: Numerical simulations were performed to determine the effect of Reynolds number and orifice to pipe diameter ratio (d o /d) on the wall mass transfer rate downstream of an orifice. The simulations were performed for d o /d of 0.475 for Reynolds number up to 70,000. The effect of d o /d was determined by performing simulations at a Reynolds number of 70,000 for d o /d of 0.375, 0.475 and 0.575. The momentum and mass transport equations were solved using the Low Reynolds Number (LRN) K-ε turbulence model. The Sherwood number (Sh) profile downstream of the orifice was in relatively good agreement with existing experimental results. The Sh increases sharply downstream of the orifice, reaching a maximum within 1–2 diameters downstream of the orifice, before relaxing back to the fully developed pipe flow value. The Sh number well downstream of the orifice was in good agreement with results for fully developed pipe flow estimated from the correlation of . The peak Sh numbers from the simulations were higher than that predicted from and .

  14. Calibration and use of filter test facility orifice plates

    Fain, D. E.; Selby, T. W.

    1984-07-01

    There are three official DOE filter test facilities. These test facilities are used by the DOE, and others, to test nuclear grade HEPA filters to provide Quality Assurance that the filters meet the required specifications. The filters are tested for both filter efficiency and pressure drop. In the test equipment, standard orifice plates are used to set the specified flow rates for the tests. There has existed a need to calibrate the orifice plates from the three facilities with a common calibration source to assure that the facilities have comparable tests. A project has been undertaken to calibrate these orifice plates. In addition to reporting the results of the calibrations of the orifice plates, the means for using the calibration results will be discussed. A comparison of the orifice discharge coefficients for the orifice plates used at the seven facilities will be given. The pros and cons for the use of mass flow or volume flow rates for testing will be discussed. It is recommended that volume flow rates be used as a more practical and comparable means of testing filters. The rationale for this recommendation will be discussed.

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

    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.

  16. Noise generated by cavitating single-hole and multi-hole orifices in a water pipe

    Testud, P.; Moussou, P.; Hirschberg, A.; Aurégan, Y.

    2007-01-01

    This paper presents an experimental study of the acoustical effects of cavitation caused by a water flow through an orifice. A circular-centered single-hole orifice and a multi-hole orifice are tested. Experiments are performed under industrial conditions: the pressure drop across the orifice varies

  17. 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

    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.)

  18. The influence of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices

    Idris, A; Pullen, K

    2013-01-01

    The effects of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices are presented in this paper. Both experimental and CFD results show that chamfering and corner radiusing improve the discharge coefficient of rotating orifices. For non-inclined rotating orifices, the discharge coefficient reduces with increasing speed, but chamfered and radiused orifices manage to have higher discharge coefficient (C d ) than the straight edge orifices. Comparing between chamfering and corner radiusing, the radiused corner orifice has the highest C d at every rotational speed. This is because the inlet radius helps guiding the flow into the orifice and avoiding flow separation at the inlet.

  19. Premixed direct injection nozzle

    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.

  20. Characterization of the full cone pressure swirl spray nozzles for the nuclear reactor containment spray system

    Jain, Manish [Department of Mechanical Engineering, I.I.T., Bombay, Powai, Mumbai (India); John, Benny [Nuclear Power Corporation of India Limited, Mumbai (India); Iyer, K.N. [Department of Mechanical Engineering, I.I.T., Bombay, Powai, Mumbai (India); Prabhu, S.V., E-mail: svprabhu@iitb.ac.in [Department of Mechanical Engineering, I.I.T., Bombay, Powai, Mumbai (India)

    2014-07-01

    Highlights: • Full cone spray pressure swirl nozzle with X-Vane is studied. • Laser illuminated imaging technique is used. • Correlations for coefficient of discharge, spray cone angle and SMD are suggested. • Droplet size and mass fraction distribution is measured. • Inviscid theory predicts the coefficient of discharge. - Abstract: The objective of the present study is to characterize a full cone pressure swirl nozzle for the Containment Spray System (CSS) of Indian Pressurized heavy Water reactors (IPHWR). The influence of Reynolds number and geometric parameters on the coefficient of discharge, spray cone angle, mass flux density distribution, droplet size distribution, Sauter mean diameter (SMD is studied for full cone pressure swirl full cone nozzles. The nozzles of orifice diameter range from 1.3 to 7.2 mm are studied. Experiments are conducted with water at room temperature as the working medium. The nozzles are operated with the pressure ranging from 1 to 8 bar. The measurements of the drop size distributions are performed with laser illuminated imaging technique. The spray cone-angle of the full cone nozzles is measured by the evaluation of images recorded with a camera using IMAGE J software. Correlations for coefficient of discharge, spray cone angle and Sauter mean diameter are suggested on the basis of the experimental results. Rosin–Rammler model and Nukiyama–Tanasawa distributions predict the mass fraction distribution reasonably well. However, the droplet size distribution is predicted by Nukiyama-Tanasawa model only.

  1. In-nozzle flow and spray characteristics for mineral diesel, Karanja, and Jatropha biodiesels

    Agarwal, Avinash Kumar; Som, Sibendu; Shukla, Pravesh Chandra; Goyal, Harsh; Longman, Douglas

    2015-01-01

    Highlights: • In-nozzle flow characterization for biodiesel sprays. • Comparison of experimental spray parameters and nozzle hole simulations. • Effect of Karanja and Jatropha biodiesel on in-nozzle cavitation. • Cavitation formation investigation with diesel and biodiesels. • Nozzle hole outlet fuel velocity profile determination for test fuels. - Abstract: Superior spray behavior of fuels in internal combustion engines lead to improved combustion and emission characteristics therefore it is necessary to investigate fuel spray behavior of new alternative fuels. This study discusses the evolution of the in-nozzle orifice parameters of a numerical simulation and the evolution of spray parameters of fuel spray in a constant-volume spray chamber during an experiment. This study compares mineral diesel, biodiesels (Karanja-and Jatropha-based), and their blends with mineral diesel. The results show that mineral diesel provides superior atomization and evaporation behavior compared to the biodiesel test fuels. Karanja biodiesel provides superior atomization and evaporation characteristics compared to Jatropha biodiesel. The qualitative comparison of simulation and experimental results in tandem shows that nozzle-hole design is a critical parameter for obtaining optimum spray behavior in the engine combustion chamber

  2. Coronal microleakage of three different dental biomaterials as intra-orifice barrier during nonvital bleaching

    Nafiseh Zarenejad

    2015-01-01

    Full Text Available Background: This study was designed to assess the microleakage of glass-ionomer (GI, mineral trioxide aggregate (MTA, and calcium-enriched mixture (CEM cement as coronal orifice barrier during walking bleaching. Materials and Methods: In this experimental study, endodontic treatment was done for 70 extracted human incisors without canal calcification, caries, restoration, resorption, or cracks. The teeth were then divided into three experimental using "Simple randomization allocation" (n = 20 and two control groups (n = 5. The three cements were applied as 3-mm intra-orifice barrier in test groups, and bleaching process was then conducted using a mixture of sodium perborate powder and distilled water, for 9 days. For leakage evaluation, bovine serum albumin marker was traced in a dual-chamber technique with Bradford indicator. The Kruskal-Wallis and Mann-Whitney tests were used for statistical analysis. Results: The mean ± standard deviation leakage of samples from negative control, positive control, GI, MTA, and CEM cement groups were 0.0, 8.9 ± 0.03, 0.47 ± 0.02, 0.48 ± 0.02, and 0.49 ± 0.02 mg/mL, respectively. Statistical analysis showed no significant difference between three experimental groups (P > 0.05. Conclusion: It is concluded that GI, MTA, and CEM cements are considered as suitable intra-orifice barrier to provide coronal seal during walking bleaching.

  3. Investigation the effects of injection pressure and compressibility and nozzle entry in diesel injector nozzle’s flow

    Seyed mohammadjavad Zeidi

    2015-04-01

    Full Text Available Investigating nozzle’s orifice flow is challenging both experimentally and theoretically. This paper focuses on simulating flow inside diesel injector nozzle via Ansys fluent v15. Validation is performed with experimental results from Winkhofler et al (2001. Several important parameters such as mass flow rate, velocity profiles and pressure profiles are used for this validation. Results include the effects of contraction inside nozzle’s orifice, effect of compressibility; effect of injection pressures and several orifice entries are also simulated in this study. For considering the effect of compressibility a user defined function used in this simulation. Cavitation model which is used in this simulation is Singhal et al. cavitation model. Presto discretization method is used for Pressure equation and second upwind discretization method is used for Momentum equation. Converging Singhal et al. cavitation model is very challenging and it needs several efforts and simulations.

  4. Energy dissipation characteristics of sharp-edged orifice plate

    Ai Wanzheng

    2015-08-01

    Full Text Available The energy loss coefficient, relating directly to the energy dissipation ratio, is an important index of this energy dissipater. In this article, this coefficient and its affecting parameters were analyzed by theoretical considerations, and their relationships were obtained by numerical simulations. It could be concluded that the energy loss coefficient of sharp-edged orifice plate and its backflow region length were mainly dominated by the contraction ratio of the orifice plate. Sharp-edged orifice plate’s energy loss coefficient and its backflow region length all increase slightly with the increase in its thickness. When Reynolds number is in the range of 9.00×104–10.3×106, Reynolds number has little impacts on energy loss coefficient and backflow region length. Two empirical expressions, relating to backflow region length and energy loss coefficient, respectively, were presented.

  5. A pulse-tube refrigerator using variable-resistance orifice

    Huang, B. J.; Sun, B. W.

    2003-01-01

    In the present study, we propose a new design of orifice pulse-tube refrigerator (VROPT) using a variable-resistance valve to replace the conventional orifice. The variable-resistance orifice (VRO) is basically a high-speed solenoidal valve similar to the fuel jet device widely used in automobile engines. By changing the frequency and periods of ON and OFF of the valve through an electronic device, we can change the flow resistance of the VRO. This thus provides a possibility for an OPT to be controlled on-line during operation. From the results obtained in the present study, we have shown that VROPT is able to achieve on-line control by regulating the duty cycle d or frequency fv of the VRO. We also show that VROPT will not loss its thermal performance as compared to conventional OPT.

  6. Orifice jet brazing process development, qualification, and initial application

    1971-05-01

    Experiments were carried out to develop acceptable procedures for brazing molybdenum alloy orifices to fuel element channel inlets of the NERVA R-1 reactor core. Results achieved with various procedures are described, and qualification tests of the selected process are documented. The recommended procedure includes preplacing of Au-Ni-Cr alloy washers and induction heating to 1600 0 F, holding two minutes, heating further to 2400 0 F, holding one minute, and allowing to cool. Inert atmosphere is used, and fixturing maintains proper positioning of the orifices. Leak testing of the joints has demonstrated reproducibly satisfactory sealing. Repair brazing is feasible if needed. (auth)

  7. Effect of plate shapes in orifice plate type flowmeters

    Moeller, S.V.

    1984-01-01

    The study of unusual plate shapes in orifice plate type flowmeters is presented, with a view to providing data for the substitution of the plate with one centered circular orifice in those applications where its use is not possible. For this purpose, six pairs of plates with different forms, with and without chamfered edges, were made and tested in a closed water loop. Results show that, generally, the use of chamfers improves the results and, in the case of perforated and slotlike orificed plates, the narrow-ness of the fluid passage tends to make unnecessary its use. (Author) [pt

  8. Reactor vessel nozzle cracks: a photoelastic study

    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

  9. Determine spray droplets on water sensitive paper (WSP) for low pressure deflector nozzle using image J

    Sies, M. F.; Madzlan, N. F.; Asmuin, N.; Sadikin, A.; Zakaria, H.

    2017-09-01

    In this study, determine of spray droplets size (SMD) using water sensitive paper (WSP) at low fluid pressure with deflector nozzle or tangential flow nozzle model Delavan AL75 and New Design Nozzle with two different type of swirl (ND2.5 A1.0 & ND2.5 B1.0). These three deflected flat sprays have used at different liquid mixing ratio. These liquid mixture ratios are pure water, 10% of lime juice + 90% of water (L10W90) and 30% of lime juice + 70% of water (L30W70). WSP is used to collect the spray droplets from nozzles. The operational liquid pressure of each nozzle is 3 bar, while air operational pressures are 3 bar and 6 bar. Then, the WSP were scanned using scanner then it was analyzed using ImageJ software. ImageJ can be used for determining the diameter of droplets size on the WSP. As the results from an experiment, the AL75 nozzle recorded the lowest Sauter mean diameter which is 193.69μm at 6 bar of pressurized air while ND2.5 A1.0 recorded the highest Sauter mean diameter which is 353.61µm at 3 bar of pressurized air. Summary from the experiment shows that the higher of droplet size is because of the lower air pressure (3 Bar). Then, increasing of liquid viscosity also increase the SMD. The orifice diameter for New Design nozzle (ND-2.5) is smaller than AL75, which are 2.5mm and 2.8mm respectively. The different nozzle design also gives effect the SMD. WSP is an alternative method to determine SMD for spray droplets with the low cost if compared to Phase Doppler Anemometry (PDA).

  10. Application of LBB to a nozzle-pipe interface

    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.

  11. Patient and physician perception of natural orifice transluminal endoscopic appendectomy

    Hucl, T.; Saglová, A.; Beneš, M.; Kocík, M.; Oliverius, M.; Valenta, Zdeněk; Špičák, J.

    2012-01-01

    Roč. 18, č. 15 (2012), s. 1800-1805 ISSN 1007-9327 Institutional research plan: CEZ:AV0Z10300504 Keywords : natural orifice transluminal endoscopic surgery * patient perception * physician perception * appendectomy * laparoscopy Subject RIV: FJ - Surgery incl. Transplants Impact factor: 2.547, year: 2012

  12. Cavitating Orifice: Flow regime transitions and low frequency sound production

    Testud, P.; Moussou, P.; Hirschberg, A.; Aurégan, Y.

    2005-01-01

    Detailed data are provided for the broadband noise in a cavitating pipe flow through a circular orifice in water. Experiments are performed under industrial conditions, i.e., with a pressure drop varying from 3 to 30 bars and a cavitation number in the range 0.10 = s = 0.77. The speed of sound

  13. Arcjet nozzle area ratio effects

    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.

  14. Arcjet Nozzle Area Ratio Effects

    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.

  15. Energy Efficiency for Biodiesel Production by Combining Two Orifices in Hydrodynamic Cavitation Reactor

    Mahlinda, Mahlinda; Djafar, Fitriana

    2014-01-01

    Research of energy efficiency for biodiesel production process by combining two orifices on  hydrodynamic cavitation reactor had been carried out. The aim of this reseach was to studied effect of the number of orifices toward increasing temperature without using external energy source to produce biodiesel that generated by cavitation effects on orifices. The results of preliminary research showed by combining two orifices arranged in series can produce the highest thermal energy reached 48oC....

  16. Injection nozzle for a turbomachine

    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.

  17. Airfoil nozzle and shroud assembly

    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.

  18. Modelling of hydrothermal characteristics of centrifugal nozzles

    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

  19. Axisymmetric thrust-vectoring nozzle performance prediction

    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

  20. Nozzle flow calculation for real gases

    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

  1. Coherent structures in a supersonic complex nozzle

    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.

  2. Head spray nozzle in reactor pressure vessel

    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.)

  3. Equivalent nozzle in thermomechanical problems

    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

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

    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.

  5. Thrust Augmentation by Airframe-Integrated Linear-Spike Nozzle Concept for High-Speed Aircraft

    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.

  6. Development of a Supersonic Atomic Oxygen Nozzle Beam Source for Crossed Beam Scattering Experiments

    Sibener, S. J.; Buss, R. J.; Lee, Y. T.

    1978-05-01

    A high pressure, supersonic, radio frequency discharge nozzle beam source was developed for the production of intense beams of ground state oxygen atoms. An efficient impedance matching scheme was devised for coupling the radio frequency power to the plasma as a function of both gas pressure and composition. Techniques for localizing the discharge directly behind the orifice of a water-cooled quartz nozzle were also developed. The above combine to yield an atomic oxygen beam source which produces high molecular dissociation in oxygen seeded rare gas mixtures at total pressures up to 200 torr: 80 to 90% dissociation for oxygen/argon mixtures and 60 to 70% for oxygen/helium mixtures. Atomic oxygen intensities are found to be greater than 10{sup 17} atom sr{sup -1} sec{sup -1}. A brief discussion of the reaction dynamics of 0 + IC1 ..-->.. I0 + C1 is also presented.

  7. Pressure Distribution on Inner Wall of Parabolic Nozzle in Laser Propulsion with Single Pulse

    Cui, Cunyan; Hong, Yanji; Wen, Ming; Song, Junling; Fang, Juan

    2011-11-01

    A system based of dynamic pressure sensors was established to study the time resolved pressure distribution on the inner wall of a parabolic nozzle in laser propulsion. Dynamic calibration and static calibration of the test system were made and the results showed that frequency response was up to 412 kHz and linear error was less than 10%. Experimental model was a parabolic nozzle and three test points were preset along one generating line. This study showed that experimental results agreed well with those obtained by numerical calculation way in pressure evolution tendency. The peak value of the calculation was higher than that of the experiment at each tested orifice because of the limitation of the numerical models. The results of this study were very useful for analyzing the energy deposition in laser propulsion and modifying numerical models.

  8. Laboratory evaluation of a vibrating orifice monodisperse aerosol generator

    Everitt, N.M.; Snelling, K.W.

    1985-02-01

    The Berglund-Liu vibrating orifice aerosol generator is capable of producing monodisperse particles in the diameter range 5 to 50 μm. Experiments have been carried out to set up and evaluate such a generator for the preparation of standard liquid (olive oil) and solid (methylene blue) aerosols in the size range 8 to 13 μm. Modifications have been made to the apparatus to improve its performance and increase its particle output. (author)

  9. Extending cavitation models to subcooled and superheated nozzle flow

    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. Preparation of spherical particles by vibrating orifice technique

    Shibata, Shuichi; Tomizawa, Atsushi; Yoshikawa, Hidemi; Yano, Tetsuji; Yamane, Masayuki

    2000-05-01

    Preparation of micrometer-sized spherical particles containing Rhodamine 6G (R6G) has been investigated for the spherical cavity micro-laser. Using phenyl triethoxy silane (PTES) as a starting material, R6G-doped monodisperse spherical particles were prepared by the vibrating orifice technique. Processing consists of two major processes: (1) Hydrolysis and polymerization of PTES and (2) Droplet formation from PTES oligomers by vibrating orifice technique. A cylindrical liquid jet passing through the orifice of 10 and 20 micrometers in diameter breaks up into equal- sized droplets by mechanical vibration. Alcohol solvent of these droplets was evaporated during flying with carrier gas and subsequently solidified in ammonium water trap. For making smooth surface and god shaped particles, control of molecular weight of PTES oligomer was essential. R6G-doped hybrid spherical particles of 4 to 10 micrometers size of cavity structure were successfully obtained. The spherical particles were pumped by a second harmonic pulse of Q- switched Nd:YAG laser and laser emission peaks were observed at wavelengths which correspond to the resonance modes.

  11. Killing rate of colony count by hydrodynamic cavitation due to square multi-orifice plates

    Dong, Zhiyong; Zhao, Wenqian

    2018-02-01

    Currently,in water supply engineering, the conventional technique of disinfection by chlorination is employed to kill pathogenic microorganisms in raw water. However, chlorine reacts with organic compounds in water and generates disinfection byproducts (DBPs), such as trihalomethanes (THMs), haloacetic acids (HAAs) etc. These byproducts are of carcinogenic, teratogenic and mutagenic effects, which seriously threaten human health. Hydrodynamic cavitation is a novel technique of drinking water disinfection without DBPs. Effects of orifice size, orifice number and orifice layout of multi-orifice plate, cavitation number, cavitation time and orifice velocity on killing pathogenic microorganisms by cavitation were investigated experimentally in a self-developed square multi-orifice plate-type hydrodynamic cavitation device. The experimental results showed that cavitation effects increased with decrease in orifice size and increase in orifice number, cavitation time and orifice velocity. Along with lowering in cavitation number, there was an increase in Reynolds shear stress,thus enhancing the killing rate of pathogenic microorganism in raw water. In addition, the killing rate by staggered orifice layout was greater than that by checkerboard-type orifice layout.

  12. Development of honeycomb type orifices for flow zoning in PFBR

    Pandey, G.K., E-mail: gkpandey@igcar.gov.in; Ramdasu, D.; Padmakumar, G.; Prakash, V.; Rajan, K.K.

    2013-09-15

    Highlights: • Cavitation free flow zoning devices are developed for reactor core in PFBR. • These devices are experimentally investigated for their hydraulic characteristics. • Pressure drop and cavitation are two main characteristics to be investigated. • Various configurations of devices utilized in different zones are discussed. • Loss coefficient for each configuration is compared and reported. -- Abstract: The prototype fast breeder reactor (PFBR) is in its advanced phase of construction at Kalpakkam, India. It is a sodium cooled, pool type reactor with two loop concept where each loop have one primary sodium pump (PSP), one secondary sodium pump (SSP) and two intermediate heat exchangers (IHX). PFBR core subassemblies (SA) are supported vertically inside the sleeves provided in the grid plate (GP). The GP acts as a coolant header through which flow is distributed among the SA to remove fission heat. Since the power profile of the reactor core is not uniform, it is necessary to distribute the coolant flow (called flow zoning) to each subassembly according to their power levels to get maximum mean outlet temperature of sodium at core outlet. To achieve this, PFBR core is divided into 15 zones such as fuel, blanket, reflector, storage, etc. according to their respective power levels. The flow zoning in the different SAs of the reactor core is achieved by installing permanent pressure dropping devices in the foot of the subassembly. Orifices having honey-comb type geometry were developed to meet the flow zoning requirements of fuel zone. These orifices being of very complex geometry requires precision methods of manufacturing to achieve the desired shape under specified tolerances. Investment casting method was optimized to manufacture this orifice plate successfully. Hydraulics of these orifices is important in achieving the required pressure drop without cavitation. The pressure drop across these orifice geometries depends mainly on geometrical

  13. Influence of spray nozzles and adjuvants in drift reduction potential in wind tunnel Influência de pontas de pulverização e adjuvantes no potencial de redução de deriva em túnel de vento

    Rodolfo Glauber Chechetto

    2013-03-01

    Full Text Available The drift is intimately linked to inappropriate use of pesticides and an important factor for reducing it, is the correct selection of spray nozzles and adjuvants. The objective of this work was to evaluate the drift potential in wind tunnel with different spray nozzles and different concentrations of adjuvants. The experiment was composed by six spray solutions (vegetable oil (in three concentrations, mineral oil, surfactant and reducing drift, which were applied with two nozzles, one pre-orifice flat fan (DG 8003 VS and other with air induction (AI 8003 VS, totaling 12 treatments, with three repetitions. The equipment used was a wind tunnel, where the drift collections were made at different points. The treatments averages were compared using Confidence Interval at 5% probability. The analysis of the percentage of drift showed that the treatments had different behaviors. The nonylphenol ethoxylate adjuvant presented the highest drift when applied with the nozzle of pre-orifice and the lowest drift when applied with the air induction. The behavior of these nozzles when the oil-based adjuvant was used showed apposite results to those obtained for the surfactant. For the DG nozzles the lowest percentage of drift, at all analyzed distances, was observed to the treatment with vegetable oil (1.0% and with the AI nozzles the lower drift was found for the treatment with nonylphenol ethoxylate (0.0625%, for the four distances in the collection. The result showed that both the spray nozzles and adjuvants alter directly the drift potential. There was no proportionately between the concentration of the oil-based adjuvant and the drift percentage.A deriva está diretamente ligada ao uso inadequado da tecnologia de aplicação de agrotóxicos, sendo a correta seleção das pontas de pulverização e adjuvantes importantes variáveis para auxiliar em sua redução. O objetivo deste trabalho foi estimar o potencial de deriva em túnel de vento com diferentes

  14. Optimization study on pin tip diameter of an impact-pin nozzle at high pressure ratio

    Kumar, C. Palani; Lee, Kwon Hee [FMTRC, Daejoo Machinery Co. Ltd., Daegu (Korea, Republic of); Park, Tae Choon; Cha, Bong Jun [Engine Components Research Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Kim, Heuy Dong [Dept. of Mechanical Engineering, Andong National University, Andong (Korea, Republic of)

    2016-09-15

    Wet compression system is typically installed in a gas turbine engine to increase the net power output and efficiency. A crucial component of the wet compression system is the nozzle which generates fine water droplets for injection into the compressor. The main objective of present work is to optimize a kind of nozzle called impact-pin spray nozzle and thereby produce better quality droplets. To achieve this, the dynamics occurring in the water jet impinging on the pin tip, the subsequent formation of water sheet, which finally breaks into water droplets, must be studied. In this manuscript, the progress on the numerical studies on impact-pin nozzle are reported. A small computational domain covering the orifice, pin tip and the region where primary atomization occurs is selected for numerical analysis. The governing equations are selected in three dimensional cartesian form and simulations are performed to predict the dynamics of water jet impinging on the pin. Systematic studies were carried out and the results leading to the choice of turbulence model and the effect of pin tip diameter are reported here. Further studies are proposed to show the future directions of the present research work.

  15. Fabrication of Si-nozzles for parallel mechano-electrospinning direct writing

    Pan, Yanqiao; Huang, YongAn; Bu, Ningbin; Yin, Zhouping

    2013-01-01

    Nozzles with micro-scale orifices drive high-resolution printing techniques for generating micro- to nano-scale droplets/lines. This paper presents the fabrication and application of Si-nozzles in mechano-electrospinning (MES). The fabrication process mainly consists of photolithography, Au deposition, inductively coupled plasma, and polydimethylsiloxane encapsulation. The 6 wt% polyethylene oxide solution is adopted to study the electrospinning behaviour and the relations between fibre diameter and process parameters in MES. A fibre grid with 250 µm spacing is able to be direct written, and the diameters are less than 3 µm. To improve the printing efficiency, positioning accuracy and flexibility, a rotatable multi-nozzle is adopted. The distance between parallel lines reduces sharply from 4.927 to 0.308 mm with the rotating angle increasing from 0° to 87°, and the fibre grids with tunable distance are achieved. This method paves the way for fabrication of addressable Si-nozzle array in parallel MES direct writing. (paper)

  16. The Impact of Manifold-to-Orifice Turning Angle on Sharp-Edge Orifice Flow Characteristics in both Cavitation and Non-Cavitation Turbulent Flow Regimes (Preprint)

    2007-06-01

    varies as the cavitation number is lowered. The third is supercavitation where the vapor pocket attachment has moved to the orifice exit and beyond but...the flow still acts as attached. For this study only the 90 degree orifice angle configuration experienced supercavitation . For all other angles

  17. Nozzle geometry for organic vapor jet printing

    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.

  18. Prototype Morphing Fan Nozzle Demonstrated

    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.

  19. Pressure heat pumping in the orifice pulse-tube refrigerator

    Boer, P.C.T. de

    1996-01-01

    The mechanism by which heat is pumped as a result of pressure changes in an orifice pulse-tube refrigerator (OPTR) is analyzed thermodynamically. The thermodynamic cycle considered consists of four steps: (1) the pressure is increased by a factor π 1 due to motion of a piston in the heat exchanger at the warm end of the regenerator; (2) the pressure is decreased by a factor π 2 due to leakage out of the orifice; (3) the pressure is further decreased due to motion of the piston back to its original position; (4) the pressure is increased to its value at the start of the cycle due to leakage through the orifice back into the pulse tube. The regenerator and the heat exchangers are taken to be perfect. The pressure is assumed to be uniform during the entire cycle. The temperature profiles of the gas in the pulse tube after each step are derived analytically. Knowledge of the temperature at which gas enters the cold heat exchanger during steps 3 and 4 provides the heat removed per cycle from this exchanger. Knowledge of the pressure as a function of piston position provides the work done per cycle by the piston. The pressure heat pumping mechanism considered is effective only in the presence of a regenerator. Detailed results are presented for the heat removed per cycle, for the coefficient of performance, and for the refrigeration efficiency as a function of the compression ratio π 1 and the expansion ratio π 2 . Results are also given for the influence on performance of the ratio of specific heats. The results obtained are compared with corresponding results for the basic pulse-tube refrigerator (BPTR) operating by surface heat pumping

  20. Multielement suppressor nozzles for thrust augmentation systems.

    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. Characterization of surface position in a liquid dispensing orifice

    Farahi, R H [ORNL; Passian, Ali [ORNL; Thundat, Thomas George [ORNL; Lereu, Aude L [ORNL; Tetard, Laurene [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Jones, Yolanda [ORNL

    2009-01-01

    Precision microdispencing technology delivers picoliter amounts of fluid for printing, electronic, optical, chemical and biomedical applications. In particular, microjetting is capable of accurate, flexible, and non-contact coating with polymers, thus allowing the functionalization of delicate microsensors such as microcantilevers. Information on various phases of droplet formation are important to control volume, uniformity, velocity and rate. One such aspect is the ringing of the meniscus after droplet breakoff which can affect subsequent drop formation. We present analysis of an optical characterization technique and experimental results on the behaviour of menisus oscillations in an orifice of a piezoelectric microjet.

  2. Numerical simulation of progressive BWR fuel inlet orifices

    Sara Lundgren; Hernan Tinoco; Aleksander Pohl; Wiktor Frid

    2005-01-01

    Full text of publication follows: A 'progressive' orifice is characterized by an edge-shaped hole that gives a Reynolds number dependent resistance coefficient. For Reynolds numbers smaller than a critical one, the resistance coefficient has a high constant value that drops to a much lower value for Reynolds numbers greater than this critical value. A similar effect is widely known for external flows around bodies of different shapes, i. e. spheres, cylinders, etc., and the sudden drop in drag coefficient is due to the shift from laminar to turbulent boundary-layer flow. Experimentally, progressive orifices have been investigated under high-pressure and high-temperature conditions by Akiba et al. (2001) for a reduced set of geometrical parameters. Using the sparse experimental data, a core stability study was carried out by Forsmaks Kraftgrupp AB that showed an improvement in core stability but without the expected reduction in pump power at normal operation. The reason for this partial success was the impossibility of optimizing the fuel inlet pressure drop owing to the limited amount of available data. Due to the high costs associated with the experimental generation of high-pressure, high-temperature data, it was considered that, if possible, the lacking data could be generated numerically at much lower cost. Therefore, the present work deals with the possibility of numerically simulate the flow through progressive orifices, and with the conditions under which to reproduce and generate resistance coefficient data by means of a commercial CFD-code. The results obtained with a two-dimensional, axisymmetric approximation show that Reynolds Averaged Navier-Stokes (RANS) turbulence models are able to qualitatively capture the physics of the phenomenon but with an earlier transition to turbulent boundary-layer flow and with an underestimation of the resistance coefficient by approximately 20 %. This underestimation of the resistance coefficient is related to the two

  3. Numerical simulation of progressive BWR fuel inlet orifices

    Sara Lundgren; Hernan Tinoco [Forsmarks Kraftgrupp AB, 742 03 Oesthammar (Sweden); Aleksander Pohl; Wiktor Frid [The Royal Institute of Technology, Dept. Energy Technology, SE-100 44 Stockholm (Sweden)

    2005-07-01

    Full text of publication follows: A 'progressive' orifice is characterized by an edge-shaped hole that gives a Reynolds number dependent resistance coefficient. For Reynolds numbers smaller than a critical one, the resistance coefficient has a high constant value that drops to a much lower value for Reynolds numbers greater than this critical value. A similar effect is widely known for external flows around bodies of different shapes, i. e. spheres, cylinders, etc., and the sudden drop in drag coefficient is due to the shift from laminar to turbulent boundary-layer flow. Experimentally, progressive orifices have been investigated under high-pressure and high-temperature conditions by Akiba et al. (2001) for a reduced set of geometrical parameters. Using the sparse experimental data, a core stability study was carried out by Forsmaks Kraftgrupp AB that showed an improvement in core stability but without the expected reduction in pump power at normal operation. The reason for this partial success was the impossibility of optimizing the fuel inlet pressure drop owing to the limited amount of available data. Due to the high costs associated with the experimental generation of high-pressure, high-temperature data, it was considered that, if possible, the lacking data could be generated numerically at much lower cost. Therefore, the present work deals with the possibility of numerically simulate the flow through progressive orifices, and with the conditions under which to reproduce and generate resistance coefficient data by means of a commercial CFD-code. The results obtained with a two-dimensional, axisymmetric approximation show that Reynolds Averaged Navier-Stokes (RANS) turbulence models are able to qualitatively capture the physics of the phenomenon but with an earlier transition to turbulent boundary-layer flow and with an underestimation of the resistance coefficient by approximately 20 %. This underestimation of the resistance coefficient is related to

  4. Surgery via natural orifices in human beings: yesterday, today, tomorrow.

    Moris, Demetrios N; Bramis, Konstantinos J; Mantonakis, Eleftherios I; Papalampros, Efstathios L; Petrou, Athanasios S; Papalampros, Alexandros E

    2012-07-01

    We performed an evaluation of models, techniques, and applicability to the clinical setting of natural orifice surgery (mainly natural orifice transluminal endoscopic surgery [NOTES]) primarily in general surgery procedures. NOTES has attracted much attention recently for its potential to establish a completely alternative approach to the traditional surgical procedures performed entirely through a natural orifice. Beyond the potentially scar-free surgery and abolishment of dermal incision-related complications, the safety and efficacy of this new surgical technology must be evaluated. Studies were identified by searching MEDLINE, EMBASE, Cochrane Library, and Entrez PubMed from 2007 to February 2011. Most of the references were identified from 2009 to 2010. There were limitations as far as the population that was evaluated (only human beings, no cadavers or animals) was concerned, but there were no limitations concerning the level of evidence of the studies that were evaluated. The studies that were deemed applicable for our review were published mainly from 2007 to 2010 (see Methods section). All the evaluated studies were conducted only in human beings. We studied the most common referred in the literature orifices such as vaginal, oral, gastric, esophageal, anal, or urethral. The optimal access route and method could not be established because of the different nature of each procedure. We mainly studied procedures in the field of general surgery such as cholecystectomy, intestinal cancers, renal cancers, appendectomy, mediastinoscopy, and peritoneoscopy. All procedures were feasible and most of them had an uneventful postoperative course. A number of technical problems were encountered, especially as far as pure NOTES procedures are concerned, which makes the need of developing new endoscopic instruments, to facilitate each approach, undeniable. NOTES is still in the early stages of development and more robust technologies will be needed to achieve reliable

  5. Flow characteristics and heat transfer performances of a semi-confined impinging array of jets: effect of nozzle geometry

    Dano, B.P.E.; Liburdy, J.A. [Oregon State Univ., Corvallis, OR (United States). Dept. of Mechanical Engineering; Kanokjaruvijit, Koonlaya [Imperial College, London (United Kingdom). Dept. of Mechanical Engineering

    2005-02-01

    The flow and heat transfer characteristics of confined jet array impingement with crossflow is investigated. Discrete impingement pressure measurements are used to obtain the jet orifice discharge flow coefficient. Digital particle image velocimetry (DPIV) and flow visualization are used to determine the flow characteristics. Two thermal boundary conditions at the impinging surface are presented: an isothermal surface, and a uniform heat flux, where thermocouple and thermochromic liquid crystal methods were used, respectively, to determine the local heat transfer coefficient. Two nozzle geometries are studied, circular and cusped ellipse. Based on the interaction with the jet impingement at the surface, the crossflow is shown to influence the heat transfer results. The two thermal boundary conditions differ in overall heat transfer correlation with the jet Reynolds number. Detailed velocity data show that the flow development from the cusped ellipse nozzle affects the wall region flow more than the circular nozzle, as influenced by the crossflow interactions. The overall heat transfer for the uniform heat flux boundary condition is found to increase for the cusped ellipse orifice. (Author)

  6. Return to axi-symmetry for pipe flows generated after a fractal orifice

    Nicolleau, F C G A, E-mail: F.Nicolleau@Sheffield.ac.uk [SFMG, Department of Mechanical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2013-12-15

    We present experimental results obtained from pipe flows generated by fractal shaped orifices or openings. We compare different fractal orifices and their efficiencies to re-generate axi-symmetric flows and to return to the standard flow generated by a perforated plate or a circular orifice plate. We consider two families of fractal openings: mono-orifice and complex orifice and emphasize the differences between the two fractal families. For the Reynolds number we used, we found that there is an optimum iteration for the fractal level above which no improvement for practical applications such as flowmetering is to be expected. The main parameters we propose for the characterization of the fractal orifice are the connexity parameter, the symmetry angle and the gap to the wall {delta}*{sub g}. The results presented here are among the first for flows forced through fractal openings and will serve as a reference for future studies and benchmarks for numerical applications. (paper)

  7. Return to axi-symmetry for pipe flows generated after a fractal orifice

    Nicolleau, F C G A

    2013-01-01

    We present experimental results obtained from pipe flows generated by fractal shaped orifices or openings. We compare different fractal orifices and their efficiencies to re-generate axi-symmetric flows and to return to the standard flow generated by a perforated plate or a circular orifice plate. We consider two families of fractal openings: mono-orifice and complex orifice and emphasize the differences between the two fractal families. For the Reynolds number we used, we found that there is an optimum iteration for the fractal level above which no improvement for practical applications such as flowmetering is to be expected. The main parameters we propose for the characterization of the fractal orifice are the connexity parameter, the symmetry angle and the gap to the wall δ* g . The results presented here are among the first for flows forced through fractal openings and will serve as a reference for future studies and benchmarks for numerical applications. (paper)

  8. Numerical analysis for the flow field past a two-staged conical orifice

    Kim, Yeon Soo; Kim, You Gon

    2001-01-01

    The objective of the paper was to measure the pressure drop and to investigate the recirculation region of the conical orifices used in Kwang-yang Iron and Steel Company. The flow field with water used as a working fluid was the turbulent flow for Reynolds number of 2x10 4 . The effective parameters for the pressure drop and the recirculation region were the conical orifice's inclined angle (θ) against the wall, the interval(L) between orifices, the relative angle of rotation(α) of the orifices, the shape of the orifice's hole(circle, rectangle, triangle) having the same area. It was found that the shape of the orifice's hold affected the pressure drop and the flow field a lot. But the other parameters did not make much differences to the pressure drop. The PISO algorithm with FLUENT code was employed

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

    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.

  10. Simulation of a Downsized FDM Nozzle

    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...

  11. Parametric Study of Sealant Nozzle

    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.

  12. Nozzle for electric dispersion reactor

    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.

  13. Effects of ambient pressure on dynamics of near-nozzle diesel sprays studied by ultrafast x-radiography

    Cheong, S. K.; Liu, J.; Shu, D.; Wang, J.; Powell, C. F.; Experimental Facilities Division

    2004-01-01

    A time-resolved x-radiographic technique has been employed for measuring the fuel distribution close to a single-hole nozzle fitted in a high-pressure diesel injector. Using a monochromatic synchrotron x-ray beam, it is possible to perform quantitative x-ray absorption measurements and obtain two-dimensional projections of the mass of the fuel spray. We have completed a series of spray measurements in the optically dense, near-nozzle region (ml 15 mm from the nozzle orifice) under ambient pressures of 1, 2, and 5.2 bar Nd2 and 1 bar SFd6 at room temperature with injection pressures of 500 and 1000 bar. The focus of the measurements is on the dynamical behaviors of the fuel jets with an emphasis on their penetration in the near-nozzle region. Careful analysis of the time-resolved, x-radiographic data revealed that the spray penetration in this near-nozzle region was not significantly affected by the limited change of the ambient pressure. In addition, well-defined features of the spray, such as the leading and trailing edges, and fluctuations of fuel mass density in the spray body, allowed us to calculate the leading, trailing, and internal speeds of the sprays

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

    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.

  15. Quantitative analysis of the side-branch orifice after bifurcation stenting using en-face processing of OCT images: a comparison between Xience V and Resolute Integrity stents.

    Minami, Yoshiyasu; Wang, Zhao; Aguirre, Aaron D; Lee, Stephen; Uemura, Shiro; Soeda, Tsunenari; Vergallo, Rocco; Raffel, Owen C; Barlis, Peter; Itoh, Tomonori; Lee, Hang; Fujimoto, James; Jang, Ik-Kyung

    2016-01-01

    Methods for intravascular assessment of the side-branch (SB) orifice after stenting are not readily available. The aim of this study was to assess the utility of an en-face projection processing for optical coherence tomography (OCT) images for SB evaluation. Measurements of the SB orifice obtained using en-face OCT images were validated using a phantom model. Linear regression modeling was applied to estimated area measurements made on the en-face images. The SB orifice was then analyzed in 88 patients with bifurcation lesions treated with either Xience V (everolimus-eluting stent) or Resolute Integrity [zotarolimus-eluting stent (ZES)]. The SB orifice area (A) and the area obstructed by struts (B) were calculated, and the %open area was evaluated as (A-B)/A*100. Linear regression modeling demonstrated that the observed departures of the intercept and slope were not significantly different from 0 (-0.12 ± 0.22, P=0.59) and 1 (1.01 ± 0.06, R(2)=0.88, P=0.87), respectively. In cases without SB dilatation, the %open area was significantly larger in the everolimus-eluting stent group (n=25) than in the ZES group [n=32; 89.2% (83.7-91.3) vs. 84.3% (78.9-87.8), P=0.04]. A significant difference in %open area between cases with and those without SB dilatation was demonstrated in the ZES group [91.4% (86.1-94.0) vs. 84.3% (78.9-87.8), P=0.04]. The accuracy of SB orifice measurement on an en-face OCT image was validated using a phantom model. This novel approach enables quantitative evaluation of the differences in SB orifice area free from struts among different stent types and different treatment strategies in vivo.

  16. Space Shuttle main engine powerhead structural modeling, stress and fatigue life analysis. Volume 3: Stress summay of blades and nozzles at FPL and 115 percent RPL loads. SSME HPFTP and HPOTP blades and nozzles

    Hammett, J. C.; Hayes, C. H.; Price, J. M.; Robinson, J. K.; Teal, G. A.; Thomson, J. M.; Tilley, D. M.; Welch, C. T.

    1983-01-01

    Gasdynamic environments applied to the turbine blades and nozzles of the HPFTP and HPOTP were analyzed. Centrifugal loads were applied to blades to account for the pump rotation of FPL and 115 percent RPL. The computer models used in the blade analysis with results presented in the form of temperature and stress contour plots are described. Similar information is given for the nozzles.

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

    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.

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

    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

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

    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)

  20. Effect of fuel temperature on the methanol spray and nozzle internal flow

    Chen, Zhifang; Yao, Anren; Yao, Chunde; Yin, Zenghui; Xu, Han; Geng, Peilin; Dou, Zhancheng; Hu, Jiangtao; Wu, Taoyang; Ma, Ming

    2017-01-01

    Highlights: • Cavitation region increases with the increasing of methanol temperature. • The nozzle exit velocity increases with the increasing of methanol temperature. • The discharge coefficient decreases with the increasing of methanol temperature. • Droplet SMD reduces when methanol temperature increases measured by PDPA system. • Droplet velocity has the maximum value when methanol temperature is 60 °C. - Abstract: The increasing of fuel temperature can reduce the droplet size and have an advantage of improving spray atomization, while investigations of the effect of temperature on the methanol injector internal flow and external spray is rare. Firstly, a detailed three dimensional numerical simulations of nozzle internal flow have been conducted to probe into the cavitation in methanol injector nozzles, and then an experimental study has been carried out to investigate the droplet size and velocity of methanol spray at various temperatures using the Phase Doppler Particle Analyzer (PDPA) detecting system. And results show that the region of cavitations in nozzle orifice enlarges as methanol temperature and injection pressure increases, and the temperature for 'super-cavitation' occurring decreases gradually with the increasing of injection pressure. Moreover, the nozzle exit velocity, discharge coefficient and cavitations number were also analyzed. However, the discharge coefficient reduces nearly equal under various pressure when the methanol temperature is higher than 60 °C. In addition, the Sauter Mean Diameter (SMD) and velocity of methanol droplet were also analyzed, and found that the droplet velocity reaches the maximum value when the methanol temperature is 60 °C.

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

    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.

  2. Effect of fuel and nozzle geometry on the off-axis oscillation of needle in diesel injectors using high-speed X-ray phase contrast imaging

    Zhang, X.; Liu, J.; Wang, J.

    2016-01-01

    The diesel spray characteristics are strongly influenced by the flow dynamics inside the injector nozzle. Moreover, the off-axis oscillation of needle could lead to variation of orifice flow in the nozzle. In this paper, the needle oscillation was investigated using high-speed X-ray phase contrast imaging and quantitative image processing. The effects of fuel, injection pressure and nozzle geometry on the needle oscillation were analyzed. The results showed that the vertical and horizontal oscillation of needle was independent on the injection pressure. The maximum oscillation range of 14μ m was found. Biodiesel application slightly decreased the needle oscillation due to high viscosity. The needle oscillation range increased generally with increasing hole number. The larger needle oscillation in multi-hole injectors was dominated by the geometry problem or production issue at lower needle lift. In addition, the influence of needle oscillation on the spray morphology was also discussed.

  3. Effect of fuel and nozzle geometry on the off-axis oscillation of needle in diesel injectors using high-speed X-ray phase contrast imaging

    Zhang, X.; Liu, J.; Wang, J.

    2016-05-01

    The diesel spray characteristics are strongly influenced by the flow dynamics inside the injector nozzle. Moreover, the off-axis oscillation of needle could lead to variation of orifice flow in the nozzle. In this paper, the needle oscillation was investigated using high-speed X-ray phase contrast imaging and quantitative image processing. The effects of fuel, injection pressure and nozzle geometry on the needle oscillation were analyzed. The results showed that the vertical and horizontal oscillation of needle was independent on the injection pressure. The maximum oscillation range of 14μ m was found. Biodiesel application slightly decreased the needle oscillation due to high viscosity. The needle oscillation range increased generally with increasing hole number. The larger needle oscillation in multi-hole injectors was dominated by the geometry problem or production issue at lower needle lift. In addition, the influence of needle oscillation on the spray morphology was also discussed.

  4. Use of direct washing of chemical dispense nozzle for defect control

    Linnane, Michael; Mack, George; Longstaff, Christopher; Winter, Thomas

    2006-03-01

    Demands for continued defect reduction in 300mm IC manufacturing are driving process engineers to examine all aspects of the chemical apply process for improvement. Historically, the defect contribution from photoresist apply nozzles has been minimized through a carefully controlled process of "dummy dispenses" to keep the photoresist in the tip "fresh" and remove any solidified material, a preventive maintenance regime involving periodic cleaning or replacing of the nozzles, and reliance on a pool of solvent within the nozzle storage block to keep the photoresist from solidifying at the nozzle tip. The industry standard has worked well for the most part but has limitations in terms of cost effectiveness and absolute defect elimination. In this study, we investigate the direct washing of the chemical apply nozzle to reduce defects seen on the coated wafer. Data is presented on how the direct washing of the chemical dispense nozzle can be used to reduce coating related defects, reduce material costs from the reduction of "dummy dispense", and can reduce equipment downtime related to nozzle cleaning or replacement.

  5. Effect of mitral orifice shape on intra-ventricular filling fluid dynamics

    Okafor, Ikechukwu; Angirish, Yagna; Yoganathan, Ajit; Santhanakrishnan, Arvind

    2013-11-01

    The natural geometry of the mitral orifice is D-shaped. However, most current designs of prosthetic valves employ O-shaped orifice geometry. The goal of this study was to compare the effect of geometrical modification between the D and O orifice on the intra-ventricular fluid dynamics during diastolic filling. The different mitral orifice geometries were incorporated into an in vitro left heart simulator consisting of a flexible-walled anatomical left ventricle (LV) physical model enclosed in an acrylic housing. Physiological flow rates and pressures were obtained via tuning systemic resistance and compliance elements in the flow loop. A programmable piston pump was used to generate the LV model wall motion. 2D Particle image velocimetry measurements were conducted along multiple longitudinal planes perpendicular to the annulus plane. During peak diastole, the incoming jet width at the LV central plane was smaller for the D-orifice than that of the O-orifice. Further, the core of the vortex ring in the D-orifice was reduced in size compared to that of the O-orifice. The spatiotemporal spreading of the inflow jet as well as the propagation of the vortex ring will be discussed. This study was funded by a grant from the National Heart, Lung and Blood Institute (RO1HL70262).

  6. Fluid flow nozzle energy harvesters

    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.

  7. Numerical study for two phase flow in the near nozzle region of turbine combustors

    Pervez, K.; Mushtaq, S.

    1999-01-01

    In the present study flow conditions in the near nozzle region of the combustion chamber have been investigated. There exists two-phase flow in this region. The overall performance and pollutant formation in the combustion chamber have been investigated. There exists two-phase flow in this region. The overall performance and pollutant formation in the combustion zone largely depends on the spray field in the near nozzle region the studies are conducted to determined the effects of multi jets on the flow pattern in the near nozzle region The phase doppler particle analyzer (PDPA) has been used to measure the velocities and sizes of the droplets. The flow field of two-phase liquid drop-air jets is formed from three injectors arranged in t line. Furthermore the two-phase flow field has been analyzed numerically also. The numerical analysis consists of two computational models, namely (i) 3 non-evaporating two-phase jets, (II) 3 evaporating two phase jets. The Eulerian-Eulerian approach in incorporated in both the numerical models. Since the flow is turbulent, a two-equation model (k-Epsilon) is implemented in the numerical analysis. Numerical solution of the conservation equation is obtained using PHOENICS computer code. Boundary conditions are provided from the experimental measurements. Numerical domain for the two models of the analysis starts at some distance (about 10 diameters of the injector orifice) where the atomization process is complete and droplet size and velocity could be measured experimentally. (author)

  8. Simple convergent-nozzle aerosol injector for single-particle diffractive imaging with X-ray free-electron lasers

    R. A. Kirian

    2015-07-01

    Full Text Available A major challenge in high-resolution x-ray free-electron laser-based coherent diffractive imaging is the development of aerosol injectors that can efficiently deliver particles to the peak intensity of the focused X-ray beam. Here, we consider the use of a simple convergent-orifice nozzle for producing tightly focused beams of particles. Through optical imaging we show that 0.5 μm particles can be focused to a full-width at half maximum diameter of 4.2 μm, and we demonstrate the use of such a nozzle for injecting viruses into a micro-focused soft-X-ray FEL beam.

  9. Three-dimensional analysis of internal flow characteristics in the injection nozzle tip of direct-injection diesel engines; Sanjigen suchi kaiseki ni yoru DI diesel kikan no nenryo funsha nozzle nai ryudo tokusei no kaimei

    Ogawa, H; Matsui, Y; Kimura, S [Nissan Motor Co. Ltd. Tokyo (Japan)

    1997-10-01

    To reduce the exhaust emissions and fuel consumption of direct-injection diesel engines, it is essential to optimize the fuel injection equipment closely related to combustion and emission characteristics. In this study, three-dimensional computation has been applied to investigate the effects of the injection nozzle specifications (e.g., sac volume, round shape at the inlet of the nozzle hole) and needle tip deviation on internal flow characteristics. The computational results revealed that the effects of the nozzle specifications and needle tip deviation with a smaller needle lift on internal flow characteristics and a general approach to optimize the injection nozzle specifications were obtained. 3 refs., 10 figs., 1 tab.

  10. Transport phenomena of macro and micro flows behind orifice and flow accelerated corrosion

    Fujisawa, Nobuyuki; Hayase, Toshiyuki; Ohara, Taku; Ikohagi, Toshiaki

    2008-01-01

    This paper describes experiment and numerical simulations for macro and micro flows behind an orifice model in a square pipe, which are carried from the viewpoint of flow accelerated corrosion (FAC). The measurements of velocity field behind the orifice model were carried out using particle image velocimetry, and the variations of velocity field with respect to the accuracy of the orifice position were studied. It is found that the reattachment behavior of the flow is highly influenced by the orifice position, which is a critical problem for predicting the pipe thinning phenomena by FAC. The DNS simulation was also conducted for calculating the macro flow behind the orifice. The result suggests that the DNS simulation is applicable to the prediction of pipe thinning macro flow for highly aged nuclear plant. The micro flow simulation can predict the pipe thinning phenomena near the wall. (author)

  11. Feasibility study of natural orifice transluminal endoscopic surgery inguinal hernia repair.

    Sherwinter, Danny A; Eckstein, Jeremy G

    2009-07-01

    A potentially less-invasive technique, transluminal surgery, may reduce or eliminate pain and decrease time to full return of activities after abdominal operations. Inguinal hernia repair is perfectly suited to the transgastric endoscopic approach and has not been previously reported. Our purpose was to evaluate the feasibility of transgastric bilateral inguinal herniorrhaphy (BIH). Feasibility study with a nonsurvival canine model. Under general anesthesia, male mongrel dogs weighing 20 to 30 kg had a dual-channel endoscope introduced into the peritoneal cavity over a percutaneously placed guidewire. An overtube with an insufflation channel was used. Peritoneoscopy was performed, and bilateral deep and superficial inguinal rings were identified. The endoscope was removed, premounted with a 4 x 6 cm acellular human dermal implant and then readvanced intraperitoneally through the overtube. The implant was then deployed across the entire myopectineal orifice and draped over the cord structures. Bioglue was then applied endoscopically, and the implant was attached to the peritoneum. After completion of bilateral repairs, the animals were killed and necropsy performed. Five dogs underwent pure natural orifice transluminal endoscopic surgery (NOTES) intraperitoneal onlay mesh (IPOM) BIH. Accurate placement and adequate myopectineal coverage was accomplished in all subjects. At necropsy no injuries to the major structures were noted but Bioglue misapplication with contamination of unintended sites did occur. Our study involved only a small number of subjects in nonsurvival experiments, and no gastric closure was used. Many of the characteristics of inguinal hernia repair are especially well suited to the transgastric approach. The repair is in line with the transgastric endoscope vector, bilateral defects are adjacent, and the IPOM technique does not require significant manipulation or novel instrumentation.

  12. Evaluation of an Experimental Model for Flat-Fan Nozzles Drift in Wind Tunnel by Image Processing

    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.

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

    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.

  14. Crack of reactor vessel upper head penetration nozzles in Korean nuclear plants

    Doh, E.; Lee, T-S.; Kim, J-Y.; Lee, C-H. [KEPCO Plant Service and Engineering Co., Ltd., Busan (Korea, Republic of)

    2014-07-01

    Since the first CRDM nozzles of reactor vessel head at Kori unit 1 in Korea were inspected in 2003, no CRDM nozzle cracks had been revealed prior to the inspection at Hanbit unit 3 in October 2012, even though many foreign plants had been reporting PWSCC cracks. In October 2012, seven axial cracks from 6 CRDM nozzles at Hanbit unit 3, and in November 2013, six axial cracks from 6 CRDM nozzles at Hanbit unit 4 were detected by TOFD Ultrasonic testing from ID of nozzles. There were confirmed to be PWSCC by Dye penetrant testing and Replica on the surface of J-groove weld of CRDM nozzles. Both plants are OPR-1000 types. All flaws started from the surface of J-groove weld at interface with OD of nozzle, but did not grow up to the top of J-groove weld, and did not make any Leak path up to head outside. The Performance Demonstration Initiative (PDI) system of CRDM nozzle inspection for Westinghouse type plants has been applied in Korea since July 2011. However, its application for OPR-1000 is still under development in Korea. The experience of PDI inspection for Westinghouse type plant contributed greatly to the detection and evaluation of PWSCC of CRDM nozzles at OPR- 1000 of Hanbit unit 3 & 4. The experimentally based procedure of flaw detection and the enhanced detection technique of examiners made it possible to detect and to determine the PWSCC indications. Embedded Flaw Repair process was approved by government authority, and the repair of the 6 CRDM nozzles in each plant was conducted by a consortium of Westinghouse and KPS. (author)

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

    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.

  16. Development of rapid mixing fuel nozzle for premixed combustion

    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

  17. Laval nozzles for cluster-jet targets

    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.

  18. Investigation of vortex clouds and droplet sizes in heated water spray patterns generated by axisymmetric full cone nozzles.

    Naz, M Y; Sulaiman, S A; Ariwahjoedi, B; Ku Shaari, Ku Zilati

    2013-01-01

    The hot water sprays are an important part of many industrial processes, where the detailed knowledge of physical phenomena involved in jet transportation, interaction, secondary breakup, evaporation, and coalescence of droplets is important to reach more efficient processes. The objective of the work was to study the water spray jet breakup dynamics, vortex cloud formation, and droplet size distribution under varying temperature and load pressure. Using a high speed camera, the spray patterns generated by axisymmetric full cone nozzles were visualized as a function water temperature and load pressure. The image analysis confirmed that the spray cone angle and width do not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The formation and decay of semitorus like vortex clouds were also noticed in spray structures generated at near water boiling point temperature. For the nozzle with smallest orifice diameter (1.19 mm), these vortex clouds were very clear at 90°C heating temperature and 1 bar water load pressure. In addition, the sauter mean diameter (SMD) of the spray droplets was also measured by using Phase Doppler Anemometry (PDA) at different locations downstream of the nozzle exit. It was noticed that SMD varies slightly w.r.t. position when measured at room temperature whereas at higher temperature values, it became almost constant at distance of 55 mm downstream of the nozzle exit.

  19. Investigation of Vortex Clouds and Droplet Sizes in Heated Water Spray Patterns Generated by Axisymmetric Full Cone Nozzles

    M. Y. Naz

    2013-01-01

    Full Text Available The hot water sprays are an important part of many industrial processes, where the detailed knowledge of physical phenomena involved in jet transportation, interaction, secondary breakup, evaporation, and coalescence of droplets is important to reach more efficient processes. The objective of the work was to study the water spray jet breakup dynamics, vortex cloud formation, and droplet size distribution under varying temperature and load pressure. Using a high speed camera, the spray patterns generated by axisymmetric full cone nozzles were visualized as a function water temperature and load pressure. The image analysis confirmed that the spray cone angle and width do not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The formation and decay of semitorus like vortex clouds were also noticed in spray structures generated at near water boiling point temperature. For the nozzle with smallest orifice diameter (1.19 mm, these vortex clouds were very clear at 90°C heating temperature and 1 bar water load pressure. In addition, the sauter mean diameter (SMD of the spray droplets was also measured by using Phase Doppler Anemometry (PDA at different locations downstream of the nozzle exit. It was noticed that SMD varies slightly w.r.t. position when measured at room temperature whereas at higher temperature values, it became almost constant at distance of 55 mm downstream of the nozzle exit.

  20. Occurrence and prevention of enhanced oxide deposition in boiler flow control orifices

    Woolsey, I.S.; Thomas, D.M.; Garbett, K.; Bignold, G.J.

    1989-10-01

    Once-through boilers, such as those of the AGRs, incorporate flow control orifices at the boiler inlet to ensure a satisfactory flow distribution and stability in the parallel flow paths of the boiler. Deposition of corrosion products in the flow control orifice leads to changes in the orifice pressure loss characteristics, which could lead to problems of flow maldistribution within the boiler, and any adverse consequences resulting from this, such as tube overheating. To date, AGR boiler inlet orifices have not suffered significant fouling due to corrosion products in the boiler feedwater. However, oxide deposition in orifices has been observed in other plants, and in experimental loops operating under conditions very similar to those at inlet to AGR boilers. The lack of deposition in AGR flow control orifices is therefore somewhat surprising. This Report describes studies carried out to examine the factors controlling oxide deposition in flow control orifices, the intention of the work being to explain why deposition has not occurred in AGR boilers to date, and to provide means of preventing deposition in the future should this prove necessary. (author)

  1. Through an Annular Turbine Nozzle

    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.

  2. Axisymmetric nozzles with chamfered contraction

    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

  3. Inactivation of Heterosigma akashiwo in ballast water by circular orifice plate-generated hydrodynamic cavitation.

    Feng, Daolun; Zhao, Jie; Liu, Tian

    2016-01-01

    The discharge of alien ballast water is a well-known, major reason for marine species invasion. Here, circular orifice plate-generated hydrodynamic cavitation was used to inactivate Heterosigma akashiwo in ballast water. In comparison with single- and multihole orifice plates, the conical-hole orifice plate yielded the highest inactivation percentage, 51.12%, and consumed only 6.84% energy (based on a 50% inactivation percentage). Repeating treatment, either using double series-connection or circling inactivation, elevated the inactivation percentage, yet consumed much more energy. The results indicate that conical-hole-generated hydrodynamic cavitation shows great potential as a pre-inactivation method for ballast water treatment.

  4. CFD study of a simple orifice pulse tube cooler

    Zhang, X. B.; Qiu, L. M.; Gan, Z. H.; He, Y. L.

    2007-05-01

    Pulse tube cooler (PTC) has the advantages of long-life and low vibration over the conventional cryocoolers, such as G-M and Stirling coolers because of the absence of moving parts in low temperature. This paper performs a two-dimensional axis-symmetric computational fluid dynamic (CFD) simulation of a GM-type simple orifice PTC (OPTC). The detailed modeling process and the general results such as the phase difference between velocity and pressure at cold end, the temperature profiles along the wall as well as the temperature oscillations at cold end with different heat loads are presented. Emphases are put on analyzing the complicated phenomena of multi-dimensional flow and heat transfer in the pulse tube under conditions of oscillating pressure. Swirling flow pattern in the pulse tube is observed and the mechanism of formation is analyzed in details, which is further validated by modeling a basic PTC. The swirl causes undesirable mixing in the thermally stratified fluid and is partially responsible for the poor overall performance of the cooler, such as unsteady cold-end temperature.

  5. Estimation of the measurement error of eccentrically installed orifice plates

    Barton, Neil; Hodgkinson, Edwin; Reader-Harris, Michael

    2005-07-01

    The presentation discusses methods for simulation and estimation of flow measurement errors. The main conclusions are: Computational Fluid Dynamics (CFD) simulation methods and published test measurements have been used to estimate the error of a metering system over a period when its orifice plates were eccentric and when leaking O-rings allowed some gas to bypass the meter. It was found that plate eccentricity effects would result in errors of between -2% and -3% for individual meters. Validation against test data suggests that these estimates of error should be within 1% of the actual error, but it is unclear whether the simulations over-estimate or under-estimate the error. Simulations were also run to assess how leakage at the periphery affects the metering error. Various alternative leakage scenarios were modelled and it was found that the leakage rate has an effect on the error, but that the leakage distribution does not. Correction factors, based on the CFD results, were then used to predict the system's mis-measurement over a three-year period (tk)

  6. Hybrid natural orifice transluminal endoscopic cholecystectomy: prospective human series.

    Cuadrado-Garcia, Angel; Noguera, Jose F; Olea-Martinez, Jose M; Morales, Rafael; Dolz, Carlos; Lozano, Luis; Vicens, Jose-Carlos; Pujol, Juan José

    2011-01-01

    Natural orifice transluminal endoscopic surgery (NOTES) makes it possible to perform intraperitoneal surgical procedures with a minimal number of access points in the abdominal wall. Currently, it is not possible to perform these interventions without the help of abdominal wall entryways, so these procedures are hybrids fusing minilaparoscopy and transluminal endoscopic surgery. This report presents a prospective clinical series of 25 patients who underwent transvaginal hybrid cholecystectomy for cholelithiasis. The study comprised a clinical series of 25 consecutive nonrandomized women who underwent a fusion transvaginal NOTES and minilaparoscopy procedure with two trocars for cholelithiasis: one 5-mm umbilical trocar and one 3-mm trocar in the upper left quadrant. The study had no control group. The scheduled surgical intervention was performed for all 25 women. No intraoperative complications occurred. One patient had mild hematuria that resolved in less than 12 h, but no other complications occurred during an average follow-up period of 140 days. Of the 25 women, 20 were discharged in 24 h, and 5 were discharged less than 12 h after the procedure. Hybrid transvaginal cholecystectomy, combining NOTES and minilaparoscopy, is a good surgical model for minimally invasive surgery. It can be performed in surgical settings where laparoscopy is practiced regularly using the instruments normally used for endoscopy and laparoscopic surgery. Due to the reproducibility of the intervention and the ease of vaginal closure, hybrid transvaginal cholecystectomy will permit further development of NOTES in the future.

  7. Laminar and turbulent nozzle-jet flows and their acoustic near-field

    Bühler, Stefan; Obrist, Dominik; Kleiser, Leonhard

    2014-01-01

    We investigate numerically the effects of nozzle-exit flow conditions on the jet-flow development and the near-field sound at a diameter-based Reynolds number of Re D = 18 100 and Mach number Ma = 0.9. Our computational setup features the inclusion of a cylindrical nozzle which allows to establish a physical nozzle-exit flow and therefore well-defined initial jet-flow conditions. Within the nozzle, the flow is modeled by a potential flow core and a laminar, transitional, or developing turbulent boundary layer. The goal is to document and to compare the effects of the different jet inflows on the jet flow development and the sound radiation. For laminar and transitional boundary layers, transition to turbulence in the jet shear layer is governed by the development of Kelvin-Helmholtz instabilities. With the turbulent nozzle boundary layer, the jet flow development is characterized by a rapid changeover to a turbulent free shear layer within about one nozzle diameter. Sound pressure levels are strongly enhanced for laminar and transitional exit conditions compared to the turbulent case. However, a frequency and frequency-wavenumber analysis of the near-field pressure indicates that the dominant sound radiation characteristics remain largely unaffected. By applying a recently developed scaling procedure, we obtain a close match of the scaled near-field sound spectra for all nozzle-exit turbulence levels and also a reasonable agreement with experimental far-field data

  8. Pengaruh Jarak dan Posisi Nozzle terhadap Daya Turbin Pelton

    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...

  9. Pengaruh Jarak dan Posisi Nozzle Terhadap Daya Turbin Pelton

    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...

  10. Palo Verde Unit 3 BMI nozzle modification

    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

  11. [Fourth branchial cleft deformity with skin orifice: a series of 10 cases].

    Huang, S L; Zhang, B; Chen, L S; Liang, L; Luo, X N; Lu, Z M; Zhang, S Y

    2016-10-07

    Objective: To report rare cases of congenital neck cutaneous sinus with an orifice near the sternoclavicular joint and to investigate their origins and managements. Methods: A total of ten patients with congenital neck cutaneous sinus having an orifice near the sternoclavicular joint treated in the Guangdong General Hospital from January 2010 to June 2015 were retrospectively analyzed. Results: There four boys and six girls, aging from 11 months to 96 months with an average of 33.4 months, and they had a common feature showing a congenital cutaneous sinus with an orifice near sternoclavicular joint. Discharge of pus from the orifice or abscess formation was commonly seen soon after infection. With bacteriological study, staphylococcus aureus was positive in five cases and klebsiella pneumonia in a case. Another orifice of fistula/sinus was not depicted in pyriform with barium swallow X-ray in five cases Ultrasound studies of three cases demonstrated anechoic (i.e., nearly black) and solid-cystic lesion near sternoclavicular joint with posterior acoustic enhancement. Magnetic resonance imaging (MRI) showed isointensity of the lesion on T1 and T2 weighted images with heterogeneous enhancement and a close relationship with sternoclavicular joint. All patients underwent laryngoscopic examination, which showed no orifice of sinus in pyriform at same side. Surgical resection of fistula/sinus was performed in all cases. The lengths of the fistula varied from 5 mm to 22 mm with an average of 11 mm. Postoperative pathological examination showed all specimens were accordance with fistula. No complications were noticed. Recurrence was not observed in the cases by following-up of 6 months to 70 months (median: 33 months). Conclusion: Congenital neck cutaneous sinus with orifice near the sternoclavicular joint maybe a special clinical phenotype of the fourth branchial cleft sinus with skin orifice in cervicothoracic junction. Differential diagnoses between low cervical diseases

  12. Experimental stress analysis of the attachment region of hemispherical shells with attached nozzles. Part 4c. Nonradial nozzle at 22-1/2 degrees 2.265 in. O.D. - 2.500 in. I.D. 4.00 in. penetration

    Maxwell, R.L.; Holland, R.W.

    1974-03-01

    The report presents the results of investigations conducted on a nonradially attached nozzle of 2.625'' O.D., 2.500'' I.D., and 4.00'' nominal penetration into the hemisphere. The nozzle is inclined at 22 1/2 0 from a radial axis. Stress values for the following types of loadings are tabulated: (1) internal pressure applied to the hemisphere and nozzle assembly, (2) an axial load applied collinear with nozzle, (3) a pure torque applied in the radial plane of the nozzle, and (4) a pure bending moment or axial couple applied in various axial planes of the nozzle. The report presents various stress vs. profile curves

  13. Orifice Mass Flow Calculation in NASA's W-8 Single Stage Axial Compressor Facility

    Bozak, Richard F.

    2018-01-01

    Updates to the orifice mass flow calculation for the W-8 Single Stage Axial Compressor Facility at NASA Glenn Research Center are provided to include the effect of humidity and incorporate ISO 5167. A methodology for including the effect of humidity into the inlet orifice mass flow calculation is provided. Orifice mass flow calculations provided by ASME PTC-19.5-2004, ASME MFC-3M-2004, ASME Fluid Meters, and ISO 5167 are compared for W-8's atmospheric inlet orifice plate. Differences in expansion factor and discharge coefficient given by these standards give a variation of about +/- 75% mass flow except for a few cases. A comparison of the calculations with an inlet static pressure mass flow correlation and a fan exit mass flow integration using test data from a 2017 turbofan rotor test in W-8 show good agreement between the inlet static pressure mass flow correlation, ISO 5167, and ASME Fluid Meters. While W-8's atmospheric inlet orifice plate violates the pipe diameter limit defined by each of the standards, the ISO 5167 is chosen to be the primary orifice mass flow calculation to use in the W-8 facility.

  14. Space Shuttle Redesigned Solid Rocket Motor nozzle natural frequency variations with burn time

    Lui, C. Y.; Mason, D. R.

    1991-01-01

    The effects of erosion and thermal degradation on the Space Shuttle Redesigned Solid Rocket Motor (RSRM) nozzle's structural dynamic characteristics were analytically evaluated. Also considered was stiffening of the structure due to internal pressurization. A detailed NASTRAN finite element model of the nozzle was developed and used to evaluate the influence of these effects at several discrete times during motor burn. Methods were developed for treating erosion and thermal degradation, and a procedure was developed to account for internal pressure stiffening using differential stiffness matrix techniques. Results were verified using static firing test accelerometer data. Fast Fourier Transform and Maximum Entropy Method techniques were applied to the data to generate waterfall plots which track modal frequencies with burn time. Results indicate that the lower frequency nozzle 'vectoring' modes are only slightly affected by erosion, thermal effects and internal pressurization. The higher frequency shell modes of the nozzle are, however, significantly reduced.

  15. Method and equipment of separation of gaseous and vaporous materials, particularly isotopes, with separation nozzles

    Becker, E.W.; Eisenbeiss, G.; Ehrfeld, W.

    1975-01-01

    The invention improves on the already known separation nozzle method by the two following steps: 1) The partial flows produced within the cascade with various shares of additional gas are introduced into the separating nozzle systems in such a manner that with regard to the additional gas, a molar fraction gradient is created which is in the opposite direction to the gradient created by the separation process. 2) The partial flows produced within the cascade with various compositions of the mixture of substances to be separated are introduced into the separating nozzle systems in such a manner that regarding the substances to be separated, a molar fraction gradient is created which is in the same direction as the molar fraction gradient formed by the separation process. Both measures can be separately applied or in combination with one another; flowsheets of the invented cascade circuits and separating nozzle systems are given. (GG/LH) [de

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

    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, ∞).

  17. Supersonic flaw detection device for nozzle

    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.)

  18. Comparative Performance of a Non-recessed Hole-entry Hybrid/Hydrostatic Conical Journal Bearing Compensated with Capillary and Orifice Restrictors

    P.G. Khakse

    2016-06-01

    Full Text Available This research paper deals with the theoretical study of comparison of capillary and orifice compensated non-recess hole-entry hydrostatic/ hybrid conical journal bearing. Modified Reynolds equation governing the flow of lubricant in the clearance space of conical journal and bearing has been solved using FEM, Newton-Raphson method and Gauss elimination method. Spherical coordinate system has been employed to obtain the results. The results have been computed for uniform distribution of holes in the circumferential direction with the range of restrictor design parameter C ̅_s2 = 0.02 - 0.1. The numerically simulated result shows, the use of orifice restrictor is to increase bearing stiffness, threshold speed and maximum pressure compared to capillary restrictor for applied radial load.

  19. Transcatheter pledget-assisted suture tricuspid annuloplasty (PASTA) to create a double-orifice valve.

    Khan, Jaffar M; Rogers, Toby; Schenke, William H; Greenbaum, Adam B; Babaliaros, Vasilis C; Paone, Gaetano; Ramasawmy, Rajiv; Chen, Marcus Y; Herzka, Daniel A; Lederman, Robert J

    2018-02-06

    Pledget-assisted suture tricuspid valve annuloplasty (PASTA) is a novel technique using marketed equipment to deliver percutaneous trans-annular sutures to create a double-orifice tricuspid valve. Tricuspid regurgitation is a malignant disease with high surgical mortality and no commercially available transcatheter solution in the US. Two iterations of PASTA were tested using trans-apical or trans-jugular access in swine. Catheters directed paired coronary guidewires to septal and lateral targets on the tricuspid annulus under fluoroscopic and echocardiographic guidance. Guidewires were electrified to traverse the annular targets and exchanged for pledgeted sutures. The sutures were drawn together and knotted, apposing septal and lateral targets, creating a double orifice tricuspid valve. Twenty-two pigs underwent PASTA. Annular and chamber dimensions were reduced (annular area, 10.1 ± 0.8 cm 2 to 3.8 ± 1.5 cm 2 (naïve) and 13.1 ± 1.5 cm 2 to 6.2 ± 1.0 cm 2 (diseased); septal-lateral diameter, 3.9 ± 0.3 mm to 1.4 ± 0.6 mm (naïve) and 4.4 ± 0.4 mm to 1.7 ± 1.0 mm (diseased); and right ventricular end-diastolic volume, 94 ± 13 ml to 85 ± 14 ml (naïve) and 157 ± 25 ml to 143 ± 20 ml (diseased)). MRI derived tricuspid regurgitation fraction fell from 32 ± 12% to 4 ± 5%. Results were sustained at 30 days. Pledget pull-through force was five-fold higher (40.6 ± 11.7N vs 8.0 ± 2.6N, P PASTA reduces annular dimensions and tricuspid regurgitation in pigs. It may be cautiously applied to selected patients with severe tricuspid regurgitation and no options. This is the first transcatheter procedure, to our knowledge, to deliver standard pledgeted sutures to repair cardiac pathology. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

  20. Investigation on Hydrodynamic Cavitation of a Restriction Orifice and Static Mixer on Crud-like Deposits

    Kim, Seong Man; Lee, Seung Won; Park, Seong Dae; Kang, Sa Rah; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2012-05-15

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core have shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice and static mixer fundamentally

  1. Effects of Hydrodynamic Cavitation of a Restriction Orifice on Crud-like Deposits

    Kim, Seong Man; Lee, Seung Won; Park, Sung Dae; Kang, Sarah; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2011-10-15

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core has shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice fundamentally

  2. Investigation on Hydrodynamic Cavitation of a Restriction Orifice and Static Mixer on Crud-like Deposits

    Kim, Seong Man; Lee, Seung Won; Park, Seong Dae; Kang, Sa Rah; Seo, Han; Bang, In Cheol

    2012-01-01

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core have shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice and static mixer fundamentally

  3. Effects of Hydrodynamic Cavitation of a Restriction Orifice on Crud-like Deposits

    Kim, Seong Man; Lee, Seung Won; Park, Sung Dae; Kang, Sarah; Seo, Han; Bang, In Cheol

    2011-01-01

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core has shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice fundamentally

  4. Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

    Papell, S.S.; Nyland, T.W.; Saiyed, N.H.

    1992-07-01

    Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomson devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1-X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band. 3 refs

  5. Internal Nozzle Flow Simulations of Gasoline-Like Fuels under Diesel Operating Conditions

    Torelli, R.; Som, S.; Pei, Y.; Zhang, Yu; Traver, Michael

    2017-05-15

    Spray formation in internal combustion engines with direct injection is strictly correlated with internal nozzle flow characteristics, which are in turn influenced by fuel physical properties and injector needle motion. This paper pre-sents a series of 3D simulations that model the in-nozzle flow in a 5-hole mini-sac diesel injector. Two gasoline-like naphtha fuels, namely full-range and light naphtha, were tested under operating conditions typical of diesel applica-tions and were compared with n-dodecane, selected from a palette used as diesel surrogates. Validated methodolo-gies from our previous work were employed to account for realistic needle motion. The multi-phase nature of the problem was described by the mixture model assumption with the Volume of Fluid method. Cavitation effects were included by means of the Homogeneous Relaxation Model and turbulence closure was achieved with the Standard k-ε model in an Unsteady Reynolds-Averaged Navier-Stokes formulation. The results revealed that injector perfor-mance and propensity to cavitation are influenced by the fuel properties. Analyses of several physical quantities were carried out to highlight the fuel-to-fuel differences in terms of mass flow rate, discharge coefficients, and fuel vapor volume fraction inside the orifices. A series of parametric investigations was also performed to assess the fuel response to varied fuel injection temperature, injection pressure, and cross-sectional orifice area. For all cases, the strict correlation between cavitation magnitude and saturation pressure was confirmed. Owing to their higher volatil-ity, the two gasoline-like fuels were characterized by higher cavitation across all the simulated conditions. Occur-rence of cavitation was mostly found at the needle seat and at the orifice inlets during the injection event’s transient, when very small gaps exist between the needle and its seat. This behavior tended to disappear at maximum needle lift, where cavitation was

  6. The influence of actuator materials and nozzle designs on electrostatic charge of pressurised metered dose inhaler (pMDI) formulations.

    Chen, Yang; Young, Paul M; Fletcher, David F; Chan, Hak Kim; Long, Edward; Lewis, David; Church, Tanya; Traini, Daniela

    2014-05-01

    To investigate the influence of different actuator materials and nozzle designs on the electrostatic charge properties of a series of solution metered dose inhaler (pMDI) aerosols. Actuators were manufactured with flat and cone nozzle designs using five different materials from the triboelectric series (Nylon, Polyethylene terephthalate, Polyethylene-High density, Polypropylene copolymer and Polytetrafluoroethylene). The electrostatic charge profiles of pMDI containing beclomethasone dipropionate (BDP) as model drug in HFA-134a propellant, with different concentrations of ethanol were studied. Electrostatic measurements were taken using a modified electrical low-pressure impactor (ELPI) and the deposited drug mass assayed chemically using HPLC. The charge profiles of HFA 134a alone have shown strong electronegativity with all actuator materials and nozzle designs, at an average of -1531.34 pC ± 377.34. The presence of co-solvent ethanol significantly reduced the negative charge magnitude. BDP reduced the suppressing effect of ethanol on the negative charging of the propellant. For all tested formulations, the flat nozzle design showed no significant differences in net charge between different actuator materials, whereas the charge profiles of cone designs followed the triboelectric series. The electrostatic charging profiles from a solution pMDI containing BDP and ethanol can be significantly influenced by the actuator material, nozzle design and formulation components. Ethanol concentration appears to have the most significant impact. Furthermore, BDP interactions with ethanol and HFA have an influence on the electrostatic charge of aerosols. By choosing different combinations of actuator materials and orifice design, the fine particle fractions of formulations can be altered.

  7. Localization of root canal orifices in mandibular second molars in relation to occlusal dimension.

    Gorduysus, O; Nagas, E; Cehreli, Z C; Gorduysus, M; Yilmaz, Z

    2009-11-01

    To evaluate the localization and distribution of canal orifices of mandibular second molar teeth in relation to the mesio-distal and bucco-lingual dimensions of coronal tissue. Fifty extracted mandibular second molar teeth were embedded into plaster blocks with their vertical axes aligned perpendicular to the horizontal plane. The teeth were photographed digitally from the occlusal aspect under 12 x magnification. Thereafter, the occlusal halves of crowns were sectioned off to expose the root canal orifices. The teeth were than photographed under the same magnification, after which the pre- and post-sectioning images of each specimen were stacked into a single file. To plot the coordinate of each canal orifice, a 0.5-mm grid analytical plane was mounted digitally on the stack so that the x- and y-axes of the plane were superimposed on the mesiodistal and buccolingual axes (bisectors) of the tooth crowns. Localization and distribution of the coordinates of the canal orifices were evaluated using the chi-square test (P = 0.05). Only one tooth displayed a single root canal orifice, located in the mesiobuccal-distolingual 'centre' of the occlusal surface. The majority of mandibular second molars had three orifices (72%), followed by those with two (16%) and four (10%). The distal canal was located lingual to the centre of the occlusal plane. The distal canal was located lingual to the centre of the occlusal plane of mandibular second molars. The possibility of observing more divergent localizations and orifice numbers should not be overlooked in clinical practice.

  8. Optimization of Orifice Geometry for Cross-Flow Mixing in a Cylindrical Duct

    Kroll, J. T.; Sowa, W. A.; Samuelsen, G. S.

    1996-01-01

    Mixing of gaseous jets in a cross-flow has significant applications in engineering, one example of which is the dilution zone of a gas turbine combustor. Despite years of study, the design of the jet injection in combustors is largely based on practical experience. The emergence of NO(x) regulations for stationary gas turbines and the anticipation of aero-engine regulations requires an improved understanding of jet mixing as new combustor concepts are introduced. For example, the success of the staged combustor to reduce the emission of NO(x) is almost entirely dependent upon the rapid and complete dilution of the rich zone products within the mixing section. It is these mixing challenges to which the present study is directed. A series of experiments was undertaken to delineate the optimal mixer orifice geometry. A cross-flow to core-flow momentum-flux ratio of 40 and a mass flow ratio of 2.5 were selected as representative of a conventional design. An experimental test matrix was designed around three variables: the number of orifices, the orifice length-to- width ratio, and the orifice angle. A regression analysis was performed on the data to arrive at an interpolating equation that predicted the mixing performance of orifice geometry combinations within the range of the test matrix parameters. Results indicate that the best mixing orifice geometry tested involves eight orifices with a long-to-short side aspect ratio of 3.5 at a twenty-three degree inclination from the center-line of the mixing section.

  9. Spray droplet velocity characterization for convergent nozzles with three different diameters

    R. Payri; B. Tormos; F.J. Salvador; L. Araneo [Universidad Politecnica de Valencia, Valencia (Spain). CMT-Motores Termicos

    2008-11-15

    The core of the present work consists of the phase-Doppler anemometry non-intrusive measurements performed at various points of diesel direct injection sprays in order to obtain the local speed of fuel droplets. The main objective was to perform extensive sets of measurements on convergent nozzles with various orifices diameters, observe and justify the differences and compare the experimental data with a theoretical approach derived by the authors in a previous work which takes into account the spray momentum flux. Experimental axial velocity profiles in different sections of the spray showed a radial distribution that was fitted with a high level of agreement to a Gaussian profile and so proving that this type of profile is a reasonable approach for the type of sprays within the scope of the present work. The experimental results showed that the velocity in the spray's axis inversely depends on axial position and that for a given axial position; higher axial velocity has been measured for the nozzles with higher spray momentum. 16 refs., 5 figs., 5 tabs.

  10. Integrated Composite Rocket Nozzle Extension, Phase I

    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...

  11. Aerospike Nozzle for Rotating Detonation Engine Application

    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...

  12. Inspections of CRDM Nozzle Penetrations in Paks NPP

    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)

  13. Inverse estimation of heat flux and temperature on nozzle throat-insert inner contour

    Chen, Tsung-Chien [Department of Power Vehicle and Systems Engineering, Chung Cheng Institute of Technology, National Defense University, Ta-Hsi, Tao-Yuan 33509 (China); Liu, Chiun-Chien [Chung Shan Institute of Science and Technology, Lung-Tan, Tao-Yuan 32526 (China)

    2008-07-01

    During the missile flight, the jet flow with high temperature comes from the heat flux of propellant burning. An enormous heat flux from the nozzle throat-insert inner contour conducted into the nozzle shell will degrade the material strength of nozzle shell and reduce the nozzle thrust efficiency. In this paper, an on-line inverse method based on the input estimation method combined with the finite-element scheme is proposed to inversely estimate the unknown heat flux on the nozzle throat-insert inner contour and the inner wall temperature by applying the temperature measurements of the nozzle throat-insert. The finite-element scheme can easily define the irregularly shaped boundary. The superior capability of the proposed method is demonstrated in two major time-varying estimation cases. The computational results show that the proposed method has good estimation performance and highly facilitates the practical implementation. An effective analytical method can be offered to increase the operation reliability and thermal-resistance layer design in the solid rocket motor. (author)

  14. Remedial measures for nozzles susceptible to PWSCC

    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

  15. Neutron Imaging study of bubble behaviors in Nanofluid Through Engineered Orifices

    Seo, Seok Bin; Bang, In Cheol; Kim, Tae Joo

    2014-01-01

    Most studies focused on the change of surface parameters through deposited nanoparticles, while Vafaei and Wen firstly discussed modification of bubble dynamics by dispersed nanoparticles in fluid as well as deposited ones. The boiling mechanism, as an effective heat transfer mode, includes bubble generation, growth, departure, and coalescence. Therefore the change of bubble dynamics can lead to the change of boiling heat transfer condition. That is, not only surface characteristics but the dispersed nanoparticles would be the essential parameters of boiling mechanism in terms of bubble dynamics. For advanced visualization of opaque fluids, the neutron imaging technique is introduced. In the present study, the bubble dynamics in nanofluid through engineered orifices was studied. The main parameters of engineered orifices are size and geometry. Photographic analysis of bubble departure frequency and averaged bubble departure volume provides as follows: With increasing orifice diameter, averaged bubble departure volume increases, while bubble departure frequency decreases. The results are attributed to enhanced capillary force by increasing contact perimeter. Averaged bubble departure volume and bubble departure frequency remain similar for three different types of orifices. But edges of the triangle and square orifice produce small bubbles which interrupts bubble generation. The converged triple contact line due to the edge may be a reason for the emerged baby bubbles. Nanofluid shows less averaged bubble departure volume and higher bubble departure frequency. Considering little change in physical properties of the fluid, interaction between bubble interface and nanoparticles may be in charge of the results

  16. Numerical investigation on effects of nozzle’s geometric parameters on the flow and the cavitation characteristics within injector’s nozzle for a high-pressure common-rail DI diesel engine

    Sun, Zuo-Yu; Li, Guo-Xiu; Chen, Chuan; Yu, Yu-Song; Gao, Guo-Xi

    2015-01-01

    Highlights: • The cavitation characteristics within nozzle were numerical studied. • The studied nozzle is from high pressure common-rail injection system. • The effects of nozzle’s geometrical parameters were considered. - Abstract: In the present paper, the influences of nozzle’s geometric parameters on the flow and the cavitation characteristics within injector’s nozzle have been numerically investigated on basis of a high-pressure common-rail DI diesel engine. For obtaining more beneficial information, five essential parameters (the pressure difference on the nozzle, circular bead of nozzle’s inlet, orifice coefficient, the ratio of nozzle’s length to orifice’s diameter, and the roughness of orifice’s inner wall) have been investigated. The variation regulations of the flow and the cavitation characteristics induced by the mentioned parameters have been observed and analysed in terms of the distributions of essential physical fields (including statistic pressure field, velocity magnitude field, turbulent kinetic energy field, mass transfer coefficient field, and vapour’s volume fraction field) and the variation regulations of crucial physical parameters (including mass flow rate, flow coefficient, average vapour’s volume fraction, average flow velocity at orifice’s outlet, and average turbulent kinetic energy at orifice’s outlet). The main results obtained in the present investigation have illustrated how the cavitation occurs, develops and extinguishes within nozzle; meanwhile, how each geometric parameter affects the flow and the cavitation characteristics within nozzle have been explored

  17. Visualization of Atomization Gas Flow and Melt Break-up Effects in Response to Nozzle Design

    Anderson, Iver; Rieken, Joel; Meyer, John; Byrd, David; Heidloff, Andy

    2011-04-01

    Both powder particle size control and efficient use of gas flow energy are highly prized goals for gas atomization of metal and alloy powder to minimize off-size powder inventory (or 'reverb') and excessive gas consumption. Recent progress in the design of close-coupled gas atomization nozzles and the water model simulation of melt feed tubes were coupled with previous results from several types of gas flow characterization methods, e.g., aspiration measurements and gas flow visualization, to make progress toward these goals. Size distribution analysis and high speed video recordings of gas atomization reaction synthesis (GARS) experiments on special ferritic stainless steel alloy powders with an Ar+O{sub 2} gas mixture were performed to investigate the operating mechanisms and possible advantages of several melt flow tube modifications with one specific gas atomization nozzle. In this study, close-coupled gas atomization under closed wake gas flow conditions was demonstrated to produce large yields of ultrafine (dia.<20 {mu}m) powders (up to 32%) with moderate standard deviations (1.62 to 1.99). The increased yield of fine powders is consistent with the dual atomization mechanisms of closed wake gas flow patterns in the near-field of the melt orifice. Enhanced size control by stabilized pre-filming of the melt with a slotted trumpet bell pour tube was not clearly demonstrated in the current experiments, perhaps confounded by the influence of the melt oxidation reaction that occurred simultaneously with the atomization process. For this GARS variation of close-coupled gas atomization, it may be best to utilize the straight cylindrical pour tube and closed wake operation of an atomization nozzle with higher gas mass flow to promote the maximum yields of ultrafine powders that are preferred for the oxide dispersion strengthened alloys made from these powders.

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

    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

  19. Comparison of turbulent flow through hexagram and hexagon orifices in circular pipes using large-eddy simulation

    Wang, Wei; Nicolleau, Franck C G A; Qin, Ning, E-mail: n.qin@sheffield.ac.uk [Department of Mechanical Engineering, The University of Sheffield, Sheffield, S1 3JD (United Kingdom)

    2016-04-15

    Characteristics of turbulent flow through a circular, a hexagon and a hexagram orifice with the same flow area in circular pipes are investigated using wall-modelled large-eddy simulation. Good agreements to available experimental data were obtained in both the mean velocity and turbulent kinetic energy. The hexagram orifice with alternating convex and concave corners introduces outwards radial velocity around the concave corners downstream of the orifice plate stronger than the hexagon orifice. The stronger outwards radial velocity transfers high momentum from the pipe centre towards the pipe wall to energize the orifice-forced vortex sheet rolling-up and leads to a delayed vortex break-down. Correspondingly, the hexagram has a more gradual flow recovery to a pipe flow and a reduced pressure drop than the hexagon orifice. Both the hexagon and hexagram orifices show an axis-switching phenomenon, which is observed from both the streamwise velocity and turbulent kinetic energy contours. To the best knowledge of the authors, this is the first comparison of orifice-forced turbulence development, mixing and flow dynamics between a regular and a fractal-based polygonal orifice. (paper)

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

    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

  1. Structural strengthening of rocket nozzle extension by means of laser metal deposition

    Honoré, M.; Brox, L.; Hallberg, M.

    2012-03-01

    Commercial space operations strive to maximize the payload per launch in order to minimize the costs of each kg launched into orbit; this yields demand for ever larger launchers with larger, more powerful rocket engines. Volvo Aero Corporation in collaboration with Snecma and Astrium has designed and tested a new, upgraded Nozzle extension for the Vulcain 2 engine configuration, denoted Vulcain 2+ NE Demonstrator The manufacturing process for the welding of the sandwich wall and the stiffening structure is developed in close cooperation with FORCE Technology. The upgrade is intended to be available for future development programs for the European Space Agency's (ESA) highly successful commercial launch vehicle, the ARIANE 5. The Vulcain 2+ Nozzle Extension Demonstrator [1] features a novel, thin-sheet laser-welded configuration, with laser metal deposition built-up 3D-features for the mounting of stiffening structure, flanges and for structural strengthening, in order to cope with the extreme load- and thermal conditions, to which the rocket nozzle extension is exposed during launch of the 750 ton ARIANE 5 launcher. Several millimeters of material thickness has been deposited by laser metal deposition without disturbing the intricate flow geometry of the nozzle cooling channels. The laser metal deposition process has been applied on a full-scale rocket nozzle demonstrator, and in excess of 15 kilometers of filler wire has been successfully applied to the rocket nozzle. The laser metal deposition has proven successful in two full-throttle, full-scale tests, firing the rocket engine and nozzle in the ESA test facility P5 by DLR in Lampoldshausen, Germany.

  2. Microcomputed tomography analysis of mesiobuccal orifices and major apical foramen in first maxillary molars.

    Spagnuolo, Gianrico; Ametrano, Gianluca; D'Antò, Vincenzo; Formisano, Anna; Simeone, Michele; Riccitiello, Francesco; Amato, Massimo; Rengo, Sandro

    2012-01-01

    Aim of the study was to determined by microcomputed tomography (µCT) the horizontal distance between the main (MB1) and the second mesiobuccal canal (MB2) orifices, the vertical distance between the MB1 and MB2 orifices planes, and the distance between the anatomic apex and major apical foramen (AF). Furthermore, we characterized the entire internal and external anatomy of the MB, distalbuccal (DB) and palatal (P) maxillary first molars roots. Twenty-two intact extracted first maxillary molars were scanned by X-ray computed transaxial µCT and then 2D and 3D images were processed and analyzed. The results showed that 77.27% of the mesiobuccal (MB) roots presented a second MB canal, and 29.41% of the MB2 were independent from the MB1 canals. In 15 teeth, there were three root canal orifices on the chamber floor, and 10 of these teeth presented MB2 canals. The mean vertical distance between the MB1 and MB2 planes was 1.68 ± 0.83 mm. Seven teeth had four orifices. The mean horizontal interorificial distance between the MB1 and MB2 orifices was 1.21 ± 0.5 mm. Accessory canals were observed in 33.33% of the roots, loops in 6.06%, while isthmuses were found in 15 of the 22 MB roots. Of the total roots, 74.24% presented one foramen, while all of the roots showed a major apical foramen that was not coincident with the anatomic apex. Our µCT analysis provided interesting features on the horizontal and vertical distance between the MB1 and MB2 orifices and on the distance of AF and anatomic apex. These results have an important clinical value because might support the endodontist in the recruitment, negotiation and obturation of maxillary first molar canal system.

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

    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.

  4. MR imaging of the entry, the abdominal communicating orifice, and the retrograde dissection in aortic dissections

    Yoshida, Y.; Mukohara, N.; Nakamura, K.; Sugimura, K.; Kono, M.

    1986-01-01

    MR imaging (1.5 T) was performed on 41 patients with aortic dissection. Entries were clearly visualized on the MR images as partial defects of the intimal flap in 18 of 21 patients (85.7%). In eight of ten patients, the locations of abdominal communicating orifices corresponded to the lowest signal intensities of the false lumina. Retrograde disections were diagnosed in all six patients from gradual increases in signal intensities of the false lumina toward the heart. MR imaging was very useful in diagnosing entries of the thoracic aorta, abdominal communicating orifices between true and false lumina, and retrograde dissections

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

    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

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

    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.

  7. Experimental study of the injection conditions influence over n-dodecane and diesel sprays with two ECN single-hole nozzles. Part I: Inert atmosphere

    Gimeno, Jaime; Bracho, Gabriela; Martí-Aldaraví, Pedro; Peraza, Jesús E.

    2016-01-01

    In this research, two Engine Combustion Network (ECN) mono-orifice nozzles, referred to as Spray C and Spray D respectively, were analyzed by performing visualization tests through Schlieren and Diffused Backlight Illumination (DBI) techniques under a wide range of ambient conditions in a non-reactive atmosphere. Spray C presents a straight nozzle designed with a sharp fillet in opposition to Spray D that has similar hydraulic properties, but with a convergent nozzle construction and a smoother corner. The experiments were carried out injecting two distinct fuels at different injection pressure ranges, from 50 MPa to 150 MPa with n-dodecane and to 200 MPa for diesel. The images were processed with Matlab home-built routines to calculate parameters as spray penetration, spreading angle, quasi-steady liquid length, as well as the spray penetration derivative respect to the square root of time, presented in this document as R-parameter. The results showed a clear influence of nozzle geometry in all measured parameters, due mainly to the nature of Spray C to cavitation, which increase the spreading angle and consequently a reduction in vapor penetration. On the other hand, fuel properties also affected spray penetration due to its dependency on viscous forces expressed in terms of the Reynolds number and its volatility in case of liquid length. This last parameter was calculated employing two processing methodologies, finding a good general agreement between them.

  8. Robotic cleaning of radwaste tank nozzles

    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

  9. Lower nozzle of PWR fuel assembly

    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.)

  10. Aeroelastic Modeling of a Nozzle Startup Transient

    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,

  11. Li/Li2 supersonic nozzle beam

    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

  12. Dual-nozzle microfluidic droplet generator

    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.

  13. Detectability of Middle Mesial Root Canal Orifices by Troughing Technique in Mandibular Molars: A Micro-computed Tomographic Study.

    Keleş, Ali; Keskin, Cangül

    2017-08-01

    The objective of the present study was to measure the orifice depth of middle mesial canals (MMCs) and evaluate the detectability of orifices using troughing preparation. For this study, 85 mandibular molar teeth with MMCs were selected from the scanned micro-computed tomographic images. The MMCs were categorized, and the distances between the MMC orifices and the cementoenamel junctions (CEJ) were recorded as the depth of the orifice. Data were evaluated with frequency analysis and a chi-square test using SPSS (SPSS Inc, Chicago, IL), and the results indicated a 5% significance level. It was found that 77.41% of the MMC orifices were at the CEJ level, whereas 5.38% and 9.69% of the MMC orifices were detectable within 1-mm and 2-mm depths from the CEJ, respectively. Of the specimens, 7.52% had MMC orifices deeper than 2 mm from the CEJ. Confluent anatomy was the most frequent configuration. No significant relation was detected between the orifice depth and MMC configuration (P > .05). It was concluded that 77.41% of the specimens did not require troughing preparation, the remaining 15.07% would require troughing, and 7.52% could not be accessed even with the troughing preparation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  14. Requirements for Vertically Installed Runoff Control Boards for the “Paddy Field Dam” and Appropriate Orifice Shapes

    Natsuki, Yoshikawa; Hideyuki, Koide; Shin-Ichi, Misawa

    While the “Paddy Field Dam” project has been recognized as an effective flood control measure, there are some cases in which the runoff control boards are vertically installed on the opening of the drainage boxes without careful consideration of the orifice shape and size. The important criteria for the runoff control boards to be satisfied are: 1. to maintain a sufficient peak runoff control function, 2. to avoid excessive ponding causing overflow, 3. to minimize the influence to the ordinary water management, and 4. to reserve sufficient orifice area to avoid blockage of the orifice with floating litters. The purpose of this study is to examine proper shapes and sizes of the orifice to satisfy the criteria for the vertically installed runoff control boards through experiments and simulations. Given the condition that the orifice has sufficient area to avoid overflow with 10 and 20 year return period rainfall event (criteria 2), the simulation results show that the orifice with horizontally wider shapes has advantages over the square or circular shapes in terms of the criteria 1 and 3. The disadvantage of the horizontally wider shapes is the blockage of the orifice with floating litters (criteria 4). In conclusion, we proposed to secure sufficient vertical distance to avoid this problem by setting a lower limit on the vertical distance and then determine the widest horizontal distance to optimize all the criteria. In addition, we have constructed the “Orifice Design Assist Tool” on the basis of the examinations in this study.

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

    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.

  16. Cavitation in flow through a micro-orifice inside a silicon microchannel

    Mishra, Chandan; Peles, Yoav

    2005-01-01

    Hydrodynamic cavitation in flows through a micro-orifice entrenched in a microchannel has been detected and experimentally investigated. Microfabrication techniques have been employed to design and develop a microfluidic device containing an 11.5μm wide micro-orifice inside a 100.2μm wide and 101.3μm deep microchannel. The flow of de-ionized water through the micro-orifice reveals the presence of multifarious cavitating flow regimes. This investigation divulges both similarities and differences between cavitation in micro-orifices and cavitation in their macroscale counterparts. The low incipient cavitation number obtained from the current experiments suggests a dominant size scale effect. Choking cavitation is observed to be independent of any pressure or velocity scale effects. However, choking is significantly influenced by the small stream nuclei residence time at such scales. Flow rate choking leads to the establishment of a stationary cavity. Large flow and cavitation hysteresis have been detected at the microscale leading to very high desinent cavitation numbers. The rapid transition from incipient bubbles to choking cavitation and subsequent supercavitation suggests the presence of radically different flow patterns at the microscale. Supercavitation results in a thick cavity, which extends throughout the microchannel, and is encompassed by the liquid. Cavitation at the microscale is expected to considerably influence the design of innovative high-speed microfluidic systems.

  17. A double parameters measurement of steam-water two-phase flow with single orifice

    Zhong Shuoping; Tong Yunxian; Yu Meiying

    1992-08-01

    A double parameters measurement of steam-water two-phase flow with single orifice is described. An on-line measurement device based on micro-computer has been developed. The measured r.m.s error of steam quality is less than 6.5% and the measured relative r.m.s. error of mass flow rate is less than 9%

  18. Orifice microreactor for the production of an organic peroxide – non-reactive and reactive characterization

    Illg, T.; Hessel, V.; Löb, P.; Schouten, J.C.

    2012-01-01

    In this article, the transfer of a two-step, biphasic, and exothermic peroxide synthesis into a microreactor assisted process is discussed as well as the non-reactive and reactive characterization of the developed orifice microreactor. Residence time distribution measurements showed nearly ideal

  19. Natural orifice transluminal endoscopic surgery vs laparoscopic ovariectomy: Complications and inflammatory response

    Martínek, J.; Ryska, O.; Filípková, T.; Doležel, R.; Juhás, Štefan; Motlík, Jan; Holubová, Monika; Nosek, V.; Rotnáglová, B.; Zavoral, M.; Ryska, M.

    2012-01-01

    Roč. 18, č. 27 (2012), s. 3558-3564 ISSN 1007-9327 Institutional research plan: CEZ:AV0Z50450515 Keywords : Natural orifice transluminal endoscopic surgery * Laparoscopy * Ovariectomy Subject RIV: FP - Other Medical Disciplines Impact factor: 2.547, year: 2012

  20. A case of ectopic ureteral orifice with hypoplastic kidney diagnosed by enhanced computed tomography

    Kishi, Mikio; Yoshimoto, Jun; Matsumura, Yosuke; Ohmori, Hiroyuki

    1983-01-01

    A case of ectopic ureteral orifice, 6 year old girl with urinary incontinece, is herein reported. Cystoscopy and excretory urogram showed absense of right half of trigone and non visualizing kidney. By enhanced computed tomography, right hypoplastic kidney was found and right nephrectomy was performed. We emphasize that enhanced computed tomography is very usefull for diagnosis of localization of hypoplastic kidney. (author)

  1. Energy Efficiency for Biodiesel Production by Combining Two Orifices in Hydrodynamic Cavitation Reactor

    Mahlinda Mahlinda

    2014-12-01

    Full Text Available Research of energy efficiency for biodiesel production process by combining two orifices on  hydrodynamic cavitation reactor had been carried out. The aim of this reseach was to studied effect of the number of orifices toward increasing temperature without using external energy source to produce biodiesel that generated by cavitation effects on orifices. The results of preliminary research showed by combining two orifices arranged in series can produce the highest thermal energy reached 48oC. Result of biodiesel production showed that yield of the highest biodiesel was 96.34% using molar ratio a methanol:oil with comparison 6:1, KOH as catalyst (1% for 50 minutes processing time. For biodiesel quality testing showed all selected parameter met the requirements of the Indonesian National Standard (SNI 04-7182:2006. Identification of biodiesel compound using GCMS showed the biodiesel compounds consisted of methyl oleate, methyl palmitate, acid linoleid, methyl stearate, palmitic acid and oleic acid with the total contents 98.39%.

  2. Experiment of cavitation erosion at the exit of a long orifice

    Yagi, Yoshinori; Murase, Michio [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

    2002-09-01

    We performed experiments to clarify mechanism of cavitation erosion and to predict cavitation erosion rate at the exit of a long orifice equipped at the chemical and volume control system in a pressurized water reactor (PWR). In order to find this mechanism, we used a high speed video camera. As the result, we observed bubble collapses near the exit of the orifice when flow condition was oscillating. So the bubble collapses due to the oscillation might cause the first stage erosion at the exit of the orifice. Using the orifice which had the cone-shaped exit, we observed that bubbles collapsed near the exit and then they collapsed at the upstream like a chain reaction. So this bubble collapse mechanism could be explained as follows: shock wave was generated by the bubble collapse near the exit, then it propagated upwards, consequently it caused the bubble collapse at the upstream. And we predicted erosion rate by evaluating the effect of the velocity and comparing the erosion resistance between the test speciment (aluminum) and the plant material (stainless steel) by means of vibratory tests. We compared the predicted erosion rate with that of the average value estimated from plant investigation, then we examined the applicability of these method to the plant evaluations. (author)

  3. A comphrehensive model for the amplification of acoustic pressure waves by single hole orifices

    Moussou, P.; Testud, Ph.; Auregan, Y.; Hirschberg, A.

    2008-01-01

    Using a parallel flow approximation, a simple model of hydrodynamic instability is proposed for describing the behavior of an orifice as an acoustic amplifier. It is shown that the growing of perturbations in the vena contracta can generate negative damping for Strouhal numbers of the order of

  4. The whistling potentiality of an orifice in a confined flow using an energetic criterion

    Testud, P.; Aurégan, Y.; Moussou, P.; Hirschberg, A.

    2009-01-01

    Using a two-source method, the scattering matrices of 10 sharp-edged thin orifices are measured under different subsonic flow conditions. The data are analysed in terms of net acoustical energy balance: the potential whistling frequency range is defined as the one associated with acoustical energy

  5. Combustor nozzles in gas turbine engines

    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.

  6. Turbocharger with variable nozzle having vane sealing surfaces

    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.

  7. Fabrication and Characterization of Device Pressure Regulation System Orifice of Manufacturing Process Gel Uranium Column Gelation External

    Triyono; Sutarni; Indra Suryawan

    2009-01-01

    The device pressure regulation orifice system of manufacturing process gel uranium on external column gelation has been made and characterized. The device consists : compressor 5.75-6.75 kg / cm 2 , air container tank, power supply 24 volts dc, solenoid valve 24 volts dc, pressure indicator 0-100 mbar, pressure indicator 0-250 mbar, mechanical valve and power electric 380 volts 50 Hz. The activity includes: installation device system and characterization with pressure variation orifice 5-75 mbar on the compressor 5.75-6.5 kg/cm 2 continuously for 1 minute. The method of installation i.e: wiring and piping to first component and support component (compressor and pressure air indicator, air container tank and pressure air indicator, solenoid valve, power supply 220 volts / 24 volts dc and orifice). After apparatus installed has been tested by the characterization without feed under air pressure varied to orifice of 5-75 mbar and device characterization with variation diameter orifice of 0.5-1 mm and orifice pressure of 5-75 mbar. The result in the characterization an every component good function, can be operation by input pressure range of 15-185 mbar orifice pressure range of 5-75 mbar. The characterization result device pressure regulation orifice system showed that: the system can be good operation of air pressure regulation orifice between 5-75 mbar with diameter orifice 0.5 mm to result gelation range of 10-25 piece / minute with variation air pressure input between 15-185 mbar of air pressure compressor 5.75-6.5 kg cm 2 . (author)

  8. Methods and systems to thermally protect fuel nozzles in combustion systems

    Helmick, David Andrew; Johnson, Thomas Edward; York, William David; Lacy, Benjamin Paul

    2013-12-17

    A method of assembling a gas turbine engine is provided. The method includes coupling a combustor in flow communication with a compressor such that the combustor receives at least some of the air discharged by the compressor. A fuel nozzle assembly is coupled to the combustor and includes at least one fuel nozzle that includes a plurality of interior surfaces, wherein a thermal barrier coating is applied across at least one of the plurality of interior surfaces to facilitate shielding the interior surfaces from combustion gases.

  9. Cavitation phenomena in a fuel injection nozzle of a diesel engine by neutron radiography

    Takenaka, N.; Kawabata, Y.; Miyata, D.; Kawabata, Y.; Sim, C. M.; Lim, I. C.

    2005-01-01

    Visualization of cavitation phenomena in a Diesel engine fuel injection nozzle was carried out by using neutron radiography system in Research Reactor Institute in Kyoto University and HANARO in Korea Atomic Energy Research Institute. A neutron chopper was synchronized to the engine rotation for high shutter speed exposures. A multi exposure method was applied to obtain a clear image as an ensemble average of the synchronized images. Some images were successfully obtained and suggested new understanding of the cavitation phenomena in a Diesel engine fuel injection nozzle

  10. Effect of Injector Nozzle Holes on Diesel Engine Performance

    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.

  11. The effect of nozzle diameter, injection pressure and ambient temperature on spray characteristics in diesel engine

    Rhaodah Andsaler, Adiba; Khalid, Amir; Sharifhatul Adila Abdullah, Nor; Sapit, Azwan; Jaat, Norrizam

    2017-04-01

    Mixture formation of the ignition process is a key element in the diesel combustion as it influences the combustion process and exhaust emission. Aim of this study is to elucidate the effects of nozzle diameter, injection pressure and ambient temperature to the formation of spray. This study investigated diesel formation spray using Computational Fluid Dynamics. Multiphase volume of fluid (VOF) behaviour in the chamber are determined by means of transient simulation, Eulerian of two phases is used for implementation of mixing fuel and air. The detail behaviour of spray droplet diameter, spray penetration and spray breakup length was visualised using the ANSYS 16.1. This simulation was done in different nozzle diameter 0.12 mm and 0.2 mm performed at the ambient temperature 500 K and 700 K with different injection pressure 40 MPa, 70 MPa and 140 MPa. Results show that high pressure influence droplet diameter become smaller and the penetration length longer with the high injection pressure apply. Smaller nozzle diameter gives a shorter length of the breakup. It is necessary for nozzle diameter and ambient temperature condition to improve the formation of spray. High injection pressure is most effective in improvement of formation spray under higher ambient temperature and smaller nozzle diameter.

  12. Experimental investigation of a two-phase nozzle flow

    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

  13. THE APPLICATION OF LASERS IN MEASUREMENT OF FLUID FLOW THROUGH DRILLING BIT NOZZLES

    Radenko Drakulić

    1993-12-01

    Full Text Available Two optical methods based on laser and video technology and digital signal and image processing techniques - Laser Doppler velocimetry (LDV and Particle image velocimetry (PIV were applied in highly accurate fluid flow measurement. Their application in jet velocity measurement of flows through drilling bit nozzles is presented. The role of nozzles in drilling technology together with procedures and tests performed on their optimization are reviewed. In addition, some experimental results for circular nozzle obtained both with LDV and PIV are elaborated. The experimental set-up and the testing procedure arc briefly discussed, as well as potential improvements in the design. Possible other applications of LDV and PIV in the domain of petroleum engineering are suggested (the paper is published in Croatian.

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

    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.

  15. A fundamental study of a variable critical nozzle flow

    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

  16. Shock wave fabricated ceramic-metal nozzles

    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

  17. New atomization nozzle for spray drying

    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.

  18. Clamp and Gas Nozzle for TIG Welding

    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

    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. Design criteria for piping and nozzles program

    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

  1. Fracture mechanics evaluation of LOFT lower plenum injection nozzle

    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

  2. Comparison of ASME Code NB-3200 and NB-3600 results for fatigue analysis of B31.1 branch nozzles

    Nitzel, M.E.; Ware, A.G.; Morton, D.K.

    1996-01-01

    Fatigue analyses wre conducted on two reactor coolant system branch nozzles in an operating PWR designed to the B31.1 Code, for which no explicit fatigue analysis was required by the licensing basis. These analyses were performed as part of resolving issues connected with NRC's Fatigue Action Plan to determine if the cumulative usage factor (CUF) for these nozzles, using the 1992 ASME Code and representative PWR transients, were comparable to nozzles designed and analyzed to the ASME Code. Both NB-3200 and NB-3600 ASME Code methods were used. NB-3200 analyses included the development of finite element models for each nozzle. Although detailed thermal transients were not available for the plant analyzed, representative transients from similar PWRs were applied in each method. CUFs calculated using NB-3200 methods were significantly less than using NB-3600. The paper points out differences in analysis methods and highlights difficulties and unknowns in performing more detailed analyses to reduce conservative assumptions

  3. The Double-Orifice Valve Technique to Treat Tricuspid Valve Incompetence.

    Hetzer, Roland; Javier, Mariano; Delmo Walter, Eva Maria

    2016-01-01

    A straightforward tricuspid valve (TV) repair technique was used to treat either moderate or severe functional (normal valve with dilated annulus) or for primary/organic (Ebstein's anomaly, leaflet retraction/tethering and chordal malposition/tethering, with annular dilatation) TV incompetence, and its long-term outcome assessed. A double-orifice valve technique was employed in 91 patients (mean age 52.6 ± 23.2 years; median age 56 years; range: 0.6-82 years) with severe tricuspid regurgitation. Among the patients, three had post-transplant iatrogenic chordal rupture, five had infective endocarditis, 11 had mitral valve insufficiency, 23 had Ebstein's anomaly, and 47 had isolated severe TV incompetence. The basic principle was to reduce the distance between the coapting leaflets, wherein the most mobile leaflet could coapt to the opposite leaflet, by creating two orifices, ensuring valve competence. The TV repair was performed through a median sternotomy or right anterior thoracotomy in the fifth intercostal space under cardiopulmonary bypass. The degree and extent of creating a double-valve orifice was determined by considering the minimal body surface area (BSA)-related acceptable TV diameter. Repair was accomplished by passing pledgeted mattress sutures from the middle of the true anterior annulus to a spot on the opposite septal annulus, located approximately two-thirds of the length of the septal annulus to avoid injury to the bundle of His. The annular apposition divides the TV into a larger anterior and a smaller posterior orifices, enabling valve closure, on both sides. In adults, the diameter of the anterior valve orifice should be 23-25 mm, and the posterior orifice 15-18 mm; thus, the total valve orifice area is 5-6 cm2. In children, the total valve orifice should be a standard deviation of 1.7 mm for a BSA of 1.0m2. During a mean follow up of 8.7 ± 1.34 years (median 10 years; range: 1.5-25.9 years) there have been no reoperations for TV insufficiency

  4. Flow and mass transfer downstream of an orifice under flow accelerated corrosion conditions

    Ahmed, Wael H.; Bello, Mufatiu M.; El Nakla, Meamer; Al Sarkhi, Abdelsalam

    2012-01-01

    Highlights: ► Mass transfer downstream of orifices was numerically and experimentally investigated. ► The surface wear pattern is measured and used to validate the present numerical results. ► The maximum mass transfer coefficient found to occur at approximately 2–3 pipe diameters downstream of the orifice. ► The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. ► The current study offered very useful information for FAC engineers for better preparation of nuclear plant inspection scope. - Abstract: Local flow parameters play an important role in characterizing flow accelerated corrosion (FAC) downstream of sudden area change in power plant piping systems. Accurate prediction of the highest FAC wear rate locations enables the mitigation of sudden and catastrophic failures, and the improvement of the plant capacity factor. The objective of the present study is to evaluate the effect of the local flow and mass transfer parameters on flow accelerated corrosion downstream of an orifice. In the present study, orifice to pipe diameter ratios of 0.25, 0.5 and 0.74 were investigated numerically by solving the continuity and momentum equations at Reynolds number of Re = 20,000. Laboratory experiments, using test sections made of hydrocal (CaSO 4 ·½H 2 O) were carried out in order to determine the surface wear pattern and validate the present numerical results. The numerical results were compared to the plants data as well as to the present experiments. The maximum mass transfer coefficient found to occur at approximately 2–3 pipe diameters downstream of the orifice. This location was also found to correspond to the location of elevated turbulent kinetic energy generated within the flow separation vortices downstream of the orifice. The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. The current study found to offer very

  5. High Viscosity Liquid Flow through the Round Orifices at Small Reynold’s Numbe rs

    V. N. Pil'gunov

    2015-01-01

    Full Text Available The paper presents research results of the mineral oil flow process with viscosity of 30 cSt through a round orifice with the sharp inlet edge of 0.9 mm in diameter. Pilot studies were conducted using a module from the transparent plexiglas that allowed to visualize hydrodynamic processes. The intake and off-take channels of the module with their sufficient extension had diameter of 20 mm (24 diameters of an orifice that allows us to consider compression of a stream as perfect. Drawing the enameled nichrome wire with a mark as a stripping isolation of 0.1 mm width enabled sounding of electric processes in the stream sections. Intensive high- frequency electric processes were revealed in cavitation stream. The paper gives experimental values of coefficientsof volumetric and mass flow at low (150 orifice. Free jet at a speed exceeding 50 m/s strikes a wall, barrier, installed at a distance of 100 diameters of the orifice: the reflection from walls, barriers shot blast, which caused intense foaming and conversion of oil into the two-phase mixture "fluid- combined air." We investigate the "life cycle" of a two-phase mixture: flotation bubbles in a viscous medium, and there was no air passes completely evolved in the dissolved state in a time not exceeding 30 minutes. Volumetric analysis of the foam allowed us to estimate the percentage of volumetric gas content of oil, which was 9% at 240С and atmospheric pressure of 97.5 kPa. An explanation of the possible cause cavitation edge at the end of a viscous fluid through an orifice with a sharp edge - appearance in fluid large tensile forces due to the centrifugal force on the particles of the fluid streams in passing peripheral sharp edge. Experimental research data flow of a viscous fluid in the annular orifice formed sharp edge and the surface of the string. Detected failure mode expiration free jet and conversion shareware transparent

  6. Organic compounds generated after the flow of water through micro-orifices: Were they synthesized?

    Tomiichi Hasegawa

    2017-08-01

    Full Text Available Micro-fluid mechanics is an important area of research in modern fluid mechanics because of its many potential industrial and biological applications. However, the field is not fully understood yet. In previous work, when passing ultrapure water (UPW in which air was dissolved (UPW* through micro-orifices, we found that the flow velocity decreased and stopped over time, and membranes were frequently formed in the orifice when the flow stopped. The membrane came from the dissolved air in UPW*, and membrane formation was closely related to electric charges generated in orifices by the flow. In the present paper, we clarified the components of the membrane and suggested a mechanism for membrane formation. We examined the effect of contaminants on the membrane formation and confirmed our previous results. We identified the chemical components of the membrane and those present in the UPW* itself by using an electron probe microanalyzer and found that the proportion of each element differed between the membrane and UPW*. Raman and infrared (IR spectroscopy showed that the membrane consisted of organic substances such as carotenoids, amides, esters, and sugars. We irradiated UPW* with ultraviolet light to cut organic chains that may be left in UPW* as contaminants. We found a similar membrane and organic compounds as in nonirradiated UPW*. Furthermore, although the UPW that was kept from contact with air after it was supplied from the UPW maker (UPW0 and bubbled with Ar gas (UPW0 bubbled with Ar formed no membrane, the UPW0 bubbled with CO2 formed thin membranes, and Raman and IR analysis showed that this membrane contained carboxylic acid salts, carotenoids, or a mixture of both. We found that electric grounding of the orifice reduces the probability of membrane formation and that the jets issuing from an aperture bear negative charges, and we assumed that the micro-orifices possess positive charges generated by flows. Consequently, we suggest that

  7. Design and analysis approach for linear aerospike nozzle

    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)

  8. Nuclear thermal rocket nozzle testing and evaluation program

    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%

  9. Evolutionary Optimization of Centrifugal Nozzles for Organic Vapours

    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.

  10. The influence of nozzle type, operating pressure, and tank-mixture components on droplet characteristics and the EPA's drift reduction rating

    The introduction of drift reduction technology (DRT) guidelines by the U. S. Environmental Protection Agency (EPA) has established testing protocols for nozzles, agrochemicals, application parameters, and combinations thereof for applying agrochemicals by certified individuals in the United States....

  11. Repair of Double Orifice Left AV Valve (DOLAVV with Endocardial Cushion Defect in Adult

    Vivek Velayudhan Pillai

    Full Text Available Abstract Double orifice left atrioventricular valve (DOLAVV or double orifice mitral valve (DOMV is a rare congenital cardiac anomaly manifesting either as an isolated lesion (mitral stenosis or mitral insufficiency or in association with other congenital cardiac defects. Signs of mitral valve disease are usually present along with the symptoms of associated coexistent congenital heart diseases. Mitral insufficiency due to annular dilatation is seen when DOLAVV is associated with endocardial cushion defects. Surgical intervention like mitral valve repair or replacement is required in 50% of patients and yields good results. We report a case of a 56-year-old lady who successfully underwent surgical correction of DOLAVV with partial atrioventricular canal defect.

  12. Burnout experiments in freon 12 using different types of orifices to simulate the core grids

    Ladeira, L.; Katsaounis, A.; Orlowski, R.; Fulfs, H.; Hofmann, K.

    1978-01-01

    This paper will report on burnout experiments carried out in freon 12 mainly at steady state and further at mass flow or power transient conditions with annular test sections axially uniformly heating either the inside or both the inside and outside rod. The runs are performed without orifice and using three different types of orifices simulating the reactor spacer grid. An important influence of the flow restriction on burnout position and value is measured. Furthermore, the comparison between the burnout correlations W2, W3, B and W2 and GE and experimental results from the literature using simple test section geometries in water and freon 12 demonstrate, that the accuracy is more or less comparable for both fluids. (orig.) [de

  13. Natural orifice translumenal endoscopic surgery (NOTES) for innovation in hepatobiliary and pancreatic surgery: preface.

    Sugimoto, Maki

    2009-01-01

    Natural orifice translumenal endoscopic surgery (NOTES) has captured the interest of interventional endoscopists and may represent the next stage of evolution of minimally invasive surgery. It provides the potential for performance of incisionless operations. It is gaining momentum both in the animal laboratory and in human case reports. Developments in the field of NOTES have led to the formation of the Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) in 2006. In this special issue, the current trends in NOTES in the field of hepatobiliary and pancreatic surgery are featured, including NOTES cholecystectomy, hepatectomy splenectomy, pancreatic necrosectomy, and the future of NOTES. In this issue, we discuss the potential benefits of these procedures in hepatobiliary and pancreatic surgery. We have just started the evaluation process for this new technology. The concept of NOTES is becoming established and is enormously advantageous for the patient. Both the surgeon and gastroenterologist should contribute to developing NOTES in making use of their specialties.

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

    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.

  15. An investigation of transient nature of the cavitating flow in injector nozzles

    He, Zhixia; Zhong, Wenjun; Wang, Qian; Jiang, Zhaochen; Fu, Yanan

    2013-01-01

    In diesel engines, the cavitating flow in nozzles greatly affects the fuel atomization characteristics and then the subsequent combustion and exhaust emissions. In this paper, with the needle lift curve on the basis of injection rate experimental data, a moving mesh generation strategy was applied for 3D simulation of the nozzle cavitating flow. Based on the third-generation synchrotrons of Shanghai Synchrotron Radiation facility (SSRF), a high-precision three-dimension structure of testing nozzle with detailed internal geometry information was obtained using X-ray radiography for a more accurate simulation. A flow visualization experiment system with a transparent scaled-up vertical multi-hole injector nozzle tip was setup. The experimental data was obtained to make a comparison to validate the calculated results and good qualitative agreement was shown between them. Afterward, the effects of needle movement on development of the cavitating flow and flow characteristics parameters were investigated. Finally, the influence of fuel temperature on development of the cavitating flow was also studied. Research of the flow characteristics for the diesel and biodiesel revealed that the flow characteristics of the biodiesel with a temperature rise of between 50 K and 60 K in injector nozzles will be similar to those of the diesel fuel. -- Highlights: ► The detailed geometry information was obtained using X-ray radiography. ► A visualization experiment system was setup for validating the numerical models. ► The detailed cavitating flow in nozzles can be gotten with a moving mesh. ► The flow characteristics between the diesel and biodiesel fuel are investigated

  16. Technical skill set training in natural orifice transluminal endoscopic surgery: how should we approach it?

    Nugent, Emmeline

    2011-03-01

    The boundaries in minimally invasive techniques are continually being pushed further. Recent years have brought new and exciting changes with the advent of natural orifice transluminal endoscopic surgery. With the evolution of this field of surgery come challenges in the development of new instruments and the actual steps of the procedure. Included in these challenges is the idea of developing a proficiency-based curriculum for training.

  17. In vivo microrobots for natural orifice transluminal surgery. Current status and future perspectives.

    Forgione, A

    2009-06-01

    The possibility to operate inside the peritoneal cavity through small holes performed in hollow organs that is presented by Natural Orifice Transluminal Endoscopic Surgery (NOTES) represents a major paradigm shift in general surgery. While this new approach seems very appealing from patients' perspectives because it eliminates completely abdominal wall aggression and promises to reduce postoperative pain, it is very challenging for surgeons because of the major constraints imposed by both the mode of access and the limited technology currently available. For this reason NOTES applications at the present time are performed by only a few surgeons and mainly to perform non-complex procedures. While new devices are under development, many of them are trying mainly to simply improve current endoscopic platforms and seem not to offer breakthrough solutions. The numerous challenges introduced by natural orifice approaches require a radical shift in the conception of new technologies in order to make this emerging operative access safe and reproducible. The convergence of several enabling technologies in the field of miniaturization, communication and micro-mechatronics brings the possibility to realize on a large scale the revolutionary concept of miniature in vivo co-operative robots. These robots provide vision and task assistance without the constraints of the entry incision and have been shown in experimental settings to possess many qualities that could be ideal to partner with Natural Orifice Surgery. This article explores the current status of microrobotics as well as presents potential future scenarios of their applications in NOTES.

  18. Performance of an Orifice Compensated Two-Lobe Hole-Entry Hybrid Journal Bearing

    J. Sharana Basavaraja

    2008-01-01

    Full Text Available The work presented in this paper aims to study the performance of a two-lobe hole-entry hybrid journal bearing system compensated by orifice restrictors. The Reynolds equation governing the flow of lubricant in the clearance space between the journal and bearing together with the equation of flow through an orifice restrictor has been solved using FEM and Galerkin's method. The bearing performance characteristics results have been simulated for an orifice compensated nonrecessed two-lobe hole-entry hybrid journal bearing symmetric configuration for the various values of offset factor (, restrictor design parameter (2, and the value of external load (0. Further, a comparative study of the performance of a two-lobe hole-entry hybrid journal bearing system with a circular hole-entry symmetric hybrid journal bearing system has also been carried out so that a designer has a better flexibility in choosing a suitable bearing configuration. The simulated numerical results indicate that for the two-lobe symmetric hole-entry hybrid journal bearing system with an offset factor ( greater than one provides 30 to 50 percent larger values of direct stiffness and direct damping coefficients as compared to a circular symmetric hole-entry hybrid journal bearing system.

  19. Analysis of film cooling in rocket nozzles

    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.

  20. Evaluation of the flow-accelerated corrosion downstream of an orifice. 1. Measurements and numerical analysis of flow field

    Utanohara, Yoichi; Nagaya, Yukinori; Nakamura, Akira; Murase, Michio

    2008-01-01

    In this study, in order to evaluate the effects of flow field on corrosion rate due to flow accelerated corrosion (FAC), an orifice flow was measured and calculated. The diameter of pipe is 50 mm and that of the orifice is 24.3 mm, and flow velocity in a water loop was set at 2.41 m/s. Flow field was measured by laser Doppler velocimetry (LDV) and particle image velocimetry (PIV), and compared with a calculation for the same flow conditions. Measurements of wall shear stress downstream of the orifice was also planed. The calculated velocity distribution of standard k-□ agreed qualitatively with PIV data and quantitatively with LDV data. Instantaneous flow field measured by PIV showed vortices around the jet from the orifice and some of them reached near the pipe wall. (author)

  1. Stress analysis of PCV nozzle junction

    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.)

  2. Flow energy piezoelectric bimorph nozzle harvester

    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.

  3. Pengaruh Jarak dan Posisi Nozzle Terhadap Daya Turbin Pelton

    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.

  4. Experimental study of the injection conditions influence over n-dodecane and diesel sprays with two ECN single-hole nozzles. Part II: Reactive atmosphere

    Payri, Raul; Salvador, F.J.; Gimeno, Jaime; Peraza, Jesús E.

    2016-01-01

    The second part of this experimental analysis, presented in this paper, seeks to go deep on the characterization of the Spray C and Spray D nozzles from the Engine Combustion Network, investigating the penetration of fuel spray at reacting conditions alongside characteristic parameters of combustion such as ignition delay and lift-off length. Both ECN mono-orifice injectors have similar nozzle flow capacity but different conicity degrees and corner sharpness, being Spray C more susceptible to cavitate. Schlieren imaging technique was employed to quantitatively measure reactive penetration and ignition delay, while lift-off length was identified through OH ∗ chemiluminescence. As in the inert part of this research, n-dodecane and commercial diesel were selected for the tests, thereby the effect of the fuel properties in the measured parameters was analyzed. Also, once again the concept of R-parameter, defined as the penetration derivative respect to the square root of time was calculated to delve into the penetration behavior. The experiments were performed in a constant pressure-flow facility able to reproduce engine-like thermodynamic conditions. Results revealed that R-parameter evolution can be divided in four stages: an inert zone, a ‘bump’, a ‘valley’ part and a quasi-steady one that overlaps the previous inert part. Those stages are highly governed by ambient temperature and oxygen concentration. Nozzle geometry and fuel properties demonstrated to have a noteworthy influence on all measured parameters.

  5. Impact of L/D on 90 Degree Sharp-Edge Orifice Flow with Manifold Passage Cross Flow (Preprint)

    2007-04-30

    that are observed by measurement as the flow transitions from non-cavitation to cavitation (turbulent flow), supercavitation , and finally separation in...include inception of cavitation, supercavitation , and separation. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...cavitation to cavitation (turbulent flow), supercavitation , and finally separation in sharp-edge 90 degree orifices. This study includes orifice L/D from

  6. Numerical simulation of progressive inlet orifices in boiling water reactor fuel

    Lundgren, Sara

    2004-07-01

    This thesis was carried out at Forsmark Nuclear Power Plant. The power plant in Forsmark consists of three boiling water reactors (BWR) which produce about 17% of Swedish electricity. In a BWR the nuclear reactions are used to boil water inside the reactor vessel. The water works both as a coolant and as a moderator and the resulting steam is used directly to run the turbines. A problem when running a BWR at low flow conditions is the density wave oscillations that might occur to the water flow inside the fuel assemblies. These oscillations arise due to the connection between power and flow rate in a heated channel with two-phase flow. In order to improve the stability performance of the channel an orifice plate is placed at the inlet of each fuel assembly. Today these orifice plates have sharp edges and a constant resistance coefficient. Experimental work has been done with progressive orifices, the edge of which is half-oval in shape. The advantage of progressive orifices is the lower pressure losses with an increase of the Reynolds number, a similar phenomenon that appears in external flow around curved bodies. Since there are high costs associated with experimental generation of high- temperature and high-pressure data, it is of some interest to be able to reproduce and generate data using Computational Fluid Dynamics (CFD). This work deals with the possibility to use the CFD-code Fluent to do numerical simulations of the flow through progressive orifices. The following conclusions may be drawn from the numerical results: All simulations using Reynolds-Averaged Navier-Stokes (RANS) turbulence models, two-dimensional and three-dimensional, capture an abrupt decrease of the resistance coefficient at higher Reynolds numbers. Two-equation models seem to under-predict the critical Reynolds number. The five-equation Reynolds Stress Model (RSM) gives a critical Reynolds number of the same order of magnitude of that measured in experiments. No major differences have

  7. Characterization of string cavitation in large-scale Diesel nozzles with tapered holes

    Gavaises, M.; Andriotis, A.; Papoulias, D.; Mitroglou, N.; Theodorakakos, A.

    2009-05-01

    The cavitation structures formed inside enlarged transparent replicas of tapered Diesel valve covered orifice nozzles have been characterized using high speed imaging visualization. Cavitation images obtained at fixed needle lift and flow rate conditions have revealed that although the conical shape of the converging tapered holes suppresses the formation of geometric cavitation, forming at the entry to the cylindrical injection hole, string cavitation has been found to prevail, particularly at low needle lifts. Computational fluid dynamics simulations have shown that cavitation strings appear in areas where large-scale vortices develop. The vortical structures are mainly formed upstream of the injection holes due to the nonuniform flow distribution and persist also inside them. Cavitation strings have been frequently observed to link adjacent holes while inspection of identical real-size injectors has revealed cavitation erosion sites in the area of string cavitation development. Image postprocessing has allowed estimation of their frequency of appearance, lifetime, and size along the injection hole length, as function of cavitation and Reynolds numbers and needle lift.

  8. Cold Flow Determination of the Internal Flow Environment Around the Submerged TVC Nozzle for the Space Shuttle SRM

    Whitesides, R. H.; Ghosh, A.; Jenkins, S. L.; Bacchus, D. L.

    1989-01-01

    A series of subscale cold flow tests was performed to quantify the gas flow characteristics at the aft end of the Space Shuttle Solid Rocket Motor. This information was used to support the analyses of the redesigned nozzle/case joint. A portion of the thermal loads at the joint are due to the circumferential velocities and pressure gradients caused primarily by the gimbaling of the submerged nose TVC nozzle. When the nozzle centerline is vectored with respect to the motor centerline, asymmetries are set up in the flow field under the submerged nozzle and immediately adjacent to the nozzle/case joint. Specific program objectives included: determination of the effects of nozzle gimbal angle and propellant geometry on the circumferential flow field; measurement of the static pressure and gas velocities in the vicinity of the nozzle/case joint; use of scaling laws to apply the subscale cold flow data to the full scale SRM; and generation of data for use in validation of 3-D computational fluid dynamic, CFD, models of the SRM flow field. These tests were conducted in the NASA Marshall Space Flight Center Airflow Facility with a 7.5 percent scale model of the aft segment of the SRM. Static and dynamic pressures were measured in the model to quantify the flow field. Oil flow data was also acquired to obtain qualitative visual descriptions of the flow field. Nozzle gimbal angles of 0, 3.5, and 7 deg were used with propellant grain configurations corresponding to motor burn times of 0, 9, 19, and 114 seconds. This experimental program was successful in generating velocity and pressure gradient data for the flow field around the submerged nose nozzle of the Space Shuttle SRM at various burn times and gimbal angles. The nature of the flow field adjacent to the nozzle/case joint was determined with oil droplet streaks, and the velocity and pressure gradients were quantified with pitot probes and wall static pressure measurements. The data was applied to the full scale SRM thru

  9. Development of top nozzle for Korean standard LWR fuel

    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.

  10. Mounting apparatus for a nozzle guide vane assembly

    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.

  11. Fluidized-bed calciner with combustion nozzle and shroud

    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

  12. Research on characteristics of varying conditions for nozzle governing stage based on dimensional analysis

    Xu, Jian-qun; Ma, Lin; Sun, You-yuan; Cao, Zu-qing

    2014-01-01

    In this paper, thermodynamic calculations of nozzle governing stage are taken based on APROS (Advanced Process Simulation), and verify through the comparison of experiment table data. The influence of partial admission on pressure ratio within the governing stage is also analyzed. The results show that partial admission not only leads to partial admission losses, but also makes an impact on pressure ratio, enthalpy and reaction degree, in turn, causes the change of efficiency. Then, the nozzle pressure ratio after the full-open valve and semi-open valve respectively, is expressed as a function of flow ratio based on dimensional analysis. This paper presents a method of thermodynamic calculation for nozzle governing stage. Comparing with the results calculated through APROS and discussing the change of pressure ratio and reaction degree, it shows that the method can reflect the influence of partial admission on pressure ratio exactly, and further improve the accuracy of existing thermodynamic calculation. - Highlights: • Partial admission is an important factor that affects the characteristics of governing stage. • Simulated test together with thermodynamic calculation to build a simplified efficiency model. • A method of thermodynamic calculation for nozzle governing stage is also proposed in this paper. • This presented method is successfully applied to a 600 MW steam turbine unit

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

    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.

  14. Influence of Fluid–Thermal–Structural Interaction on Boundary Layer Flow in Rectangular Supersonic Nozzles

    Kalyani Bhide

    2018-03-01

    Full Text Available The aim of this work is to highlight the significance of Fluid–Thermal–Structural Interaction (FTSI as a diagnosis of existing designs, and as a means of preliminary investigation to ensure the feasibility of new designs before conducting experimental and field tests. The novelty of this work lies in the multi-physics simulations, which are, for the first time, performed on rectangular nozzles. An existing experimental supersonic rectangular converging/diverging nozzle geometry is considered for multi-physics 3D simulations. A design that has been improved by eliminating the sharp throat is further investigated to evaluate its structural integrity at design Nozzle Pressure Ratio (NPR 3.67 and off-design (NPR 4.5 conditions. Static structural analysis is performed by unidirectional coupling of pressure loads from steady 3D Computational Fluid Dynamics (CFD and thermal loads from steady thermal conduction simulations, such that the simulations represent the experimental set up. Structural deformation in the existing design is far less than the boundary layer thickness, because the impact of Shock wave Boundary Layer Interaction (SBLI is not as severe. FTSI demonstrates that the discharge coefficient of the improved design is 0.99, and its structural integrity remains intact at off-design conditions. This proves the feasibility of the improved design. Although FTSI influence is shown for a nozzle, the approach can be applied to any product design cycle, or as a prelude to building prototypes.

  15. Effects of nozzle types and 2,4-D formulations on spray deposition.

    Contiero, Robinson L; Biffe, Denis F; Constantin, Jamil; de Oliveira, Rubem S; Braz, Guilherme B P; Lucio, Felipe R; Schleier, Jerome J

    2016-12-01

    The objective of this study was to evaluate the effects of nozzle types and 2,4-D formulations on spray deposition on different targets. Two field experiments were carried out in a completely randomized design, and treatments were arranged in a factorial scheme. Species in experiment 1 were Sumatran fleabane (Conyza sumatrensis) and Brazil pusley (Richardia brasiliensis) and in experiment 2 were soybeans (Glycine max) and Benghal dayflower (Commelina benghalensis). For both experiments, the first factor corresponded to spray nozzles with different settings (AD 110.015 - 61 and 105 L ha -1 ; AD 015-D - 75 and 146 L ha -1 ; XR 110.0202 - 200 L ha -1 ; and ADIA-D 110.02 - 208 L ha -1 ) and the second factor consisted of two formulations of 2,4-D (amine and choline). The formulation of 2,4-D choline has contained Colex-D™ Technology. Similar or higher spray deposition was observed on the leaves and artificial targets when using 2,4-D choline as compared to the 2,4-D amine formulation, and these differences in deposition were more evident for nozzles applying lower spray volumes. Deposition was more affected by nozzle type when amine formulation was used, compared to choline formulation.

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

    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.

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

    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

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

    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.

  19. 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

    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)

  20. Elastic stresses at reinforced nozzles in spherical shells with pressure and moment loading. Phase report 117-9

    Rodabaugh, E.C.; Gwaltney, R.C.

    1975-01-01

    The ASME Boiler and Pressure Vessel Code gives design guidance for nozzles in pressure vessels in the form of ''stress indices.'' These stress indices enable the designer of Class 1 nuclear pressure vessels to quickly determine the magnitude of stresses due to internal pressure loading; a task otherwise requiring an expensive and time-consuming stress analysis. The Code gives stress indices for nozzles in both heads and cylindrical vessels. Results of calculations of stresses in spherical heads or vessels are summarized. The validity of the Code indices for this geometry is examined and, as a result, a few relatively minor changes are recommended. The definitions involved in the use of the Code stress indices are not sufficiently clear and explicit. Accordingly, recommendations for changes in the Code to improve these defintions as well as to correct some obvious errors are presented. These recommendations apply to nozzles in cylindrical vessels and any type of formed head (e.g., spherical, elliptical, torispherical). However, the data presented herein apply only to isolated nozzles in spherical heads or in other heads where the radius of curvature in the vicinity of the nozzle is sphere-like, e.g., as in the center of a torispherical head. (U.S.)

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

    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

  2. Nozzle evaluation for Project W-314

    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

  3. Bottom nozzle of a LWR fuel assembly

    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

  4. Airfoil shape for a turbine nozzle

    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.

  5. The Performance Test for Reactor Coolant Pump (RCP) adopting Variable Restriction Orifice Type Control Valve

    Kim, S.; Bae, B. U.; Cho, Y. J. and others

    2014-05-15

    The design values of the RCPTF are 17.2 MPa, 343 .deg. C, 11.7 m{sup 3}/s, and 13 MW in the maximum pressure, temperature, flow rate, and electrical power, respectively. In the RCPTF, various types of tests can be performed including a hydraulic performance test to acquire a H-Q curve as well seal transient tests, thrust bearing transient test, cost down test, NPSHR verification test, and so on. After a commissioning startup test was successfully perfomed, mechanical structures are improved including a flow stabilizer and variable restriction orifice. Two- branch pipe (Y-branch) was installed to regulate the flow rate in the range of performance tests. In the main pipe, a flow restrictor (RO: Restriction Orifice) for limiting the maximum flow rate was installed. In the branch pipe line, a globe valve and a butterfly valves for regulating the flow rate was located on the each branch line. When the pressure loss of the valve side is smaller than that of the RO side, the flow rate of valve side was increasing and the flow disturbance was occurred in the lower pipe line. Due to flow disturbnace, it is to cause an error when measuring RCP head and flow measurement of the venturi flow meter installed in the lower main pipe line, and thus leading to a decrease in measurement accuracy as a result. To increase the efficiency of the flow control availability of the test facility, the variable restriction orifice (VRO) type flow control valve was designed and manufactured. In the RCPTF in KAERI, the performance tests and various kinds of transient tests of the RCP were successfully performed. In this study, H-Q curve of the pump using the VRO revealed a similar trend to the result from two ROs. The VRO was confirmed to effectively cover the full test range of the flow rate.

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

    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.

  7. Assessing transgastric Natural Orifice Transluminal Endoscopic Surgery prior to clinical implementation

    Donatsky, Anders Meller

    2014-01-01

    The objective was to investigate whether transgastric Natural Orifice Transluminal Endoscopic Surgery (NOTES) could be implemented safely in clinical practice. The experimental studies proved ultrasonography guided access through the stomach to be feasible and safe without iatrogenic complications......-abdominal abscess formation as a result of contamination from the access route was still present. To reduce this contamination, mouthwash with chlorhexidine was effective in a human randomised study. The same study also found significant higher bacterial load in the stomach of patients using proton pump inhibitor...

  8. Numerical simulation of trans-critical carbon dioxide (R744) flow through short tube orifices

    Garcia-Valladares, O. [Centro de Investigacion en Energia de la Universidad Nacional Autonoma de Mexico, Privada Xochicalco S/N, Apdo. Postal 34, 62580 Temixco, Morelos (Mexico)

    2006-02-01

    A detailed one-dimensional numerical simulation of the fluid-dynamic behaviour of short tube orifices expansion devices working with trans-critical carbon dioxide (CO{sub 2} or R744) has been developed. The discretized governing equations are coupled using an implicit step by step method. A special treatment has been implemented in order to consider transitions (subcooled liquid region and equilibrium two-phase region). The numerical model allows analysis of aspects such as geometry, different working conditions, critical or non-critical flow conditions, etc. Comparison of the numerical simulation with experimental data presented in the technical literature will be shown in the present article. (author)

  9. Development of a Virtual Reality Simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) Cholecystectomy Procedure.

    Ahn, Woojin; Dargar, Saurabh; Halic, Tansel; Lee, Jason; Li, Baichun; Pan, Junjun; Sankaranarayanan, Ganesh; Roberts, Kurt; De, Suvranu

    2014-01-01

    The first virtual-reality-based simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) is developed called the Virtual Translumenal Endoscopic Surgery Trainer (VTESTTM). VTESTTM aims to simulate hybrid NOTES cholecystectomy procedure using a rigid scope inserted through the vaginal port. The hardware interface is designed for accurate motion tracking of the scope and laparoscopic instruments to reproduce the unique hand-eye coordination. The haptic-enabled multimodal interactive simulation includes exposing the Calot's triangle and detaching the gall bladder while performing electrosurgery. The developed VTESTTM was demonstrated and validated at NOSCAR 2013.

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

    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

  11. Ratchetting and creep-fatigue evaluation for nozzle-to-cylinder intersection

    Barsoum, R.S.; Loomis, R.W.; Stewart, B.D.

    1976-01-01

    The study is part of an analytical investigation on the applicability of the simplified ratchetting and creep-fatigue rules to LMFBR component geometry. Both the detailed inelastic rules and the simplified elastic rules are applied to the results obtained from a three-dimensional finite element analysis of the nozzle-to-cylinder intersection. The results of both evaluations are compared at several locations on the surface, and an assessment of the degree of conservatism of the simplified methods is discussed

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

    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

  13. Analysis of film cooling in rocket nozzles

    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.

  14. EFFECTS OF NATURAL ORIFICE SECRETIONS IN PERITONEAL CAVITY IN THE BACKGROUND OF NATURAL ORIFICE TRANSLUMINAL ENDOSCOPIC SURGERY (NOTES AN EXPERIMENTAL STUDY IN ANIMALS

    Devendra

    2015-03-01

    Full Text Available Natural Orifice Transluminal Endoscopic Surgery (NOTES is a new form of minimally invasive surgery which eliminates traditional skin incisions by accessing internal body cavities through natural orifices. In our experimental animal study, we compared the incidences intraperitoneal abscess formation , culture swab of peritoneal cavity positive for organism, intraperitoneal adhesion formation and mean adhesion score before and after lavaging the portal of entry of albino rat , i.e. transgastric and transvaginal. On vaginal route as a portal of entry into peritoneal cavity , on the 7th day , 66% rats developed abscesses , 88% rats had culture swab positive and 88% rats developed intraperitoneal adhesion (grade - 2 before any cleansing of vaginal cavity with antiseptic solution . Now after lavage with povidone iodine solution, only 11% developed abscesses , 22% were peritoneal swab culture positive and 33% had interbowel and parietal adhesion of (grade 0 - 1. On 21 st day , the complication observed was adhesion formation in pre lavage group of 66% incidence and 16% after vaginal lavage. The incidence of complications were reduced significantly after lavage with antiseptic solution as shown by p values (p<0.01 for abscess formation, p< 0.01 for culture positivity and p< 0.01 for adhesions formation. Also the mean adhesion scoring was significantly reduced (p <0.02 after vaginal lavage on the 7 th day. Gastric route as the portal of entry into the peritoneal cavity, again the same variables were compared on the 7th and the 21st day , but wash was given with antibiotic solution (Cefazolin. On the 7th day , 44% had abscesses, 77% were culture positive and 66% had adhesions (Grade 1 - 2 before gastric lavage with antibiotic solution . After wash of stomach, 11% were culture positive and 44% developed adhesions (Grade 0 - 1. Here, abscess formation (p<0.02 and mean adhesion scoring (p<0.05 were significantly reduced after stomach wash. On the 21st day

  15. Modelling of fluid flow through short tube orifices under metastable conditions: A new numerical validation approach for evaluating the mass flow rate with refrigerant mixtures (HFC-407C and HFC-410A)

    García-Valladares, O.; Santoyo, E.

    2014-01-01

    In a previous work, one-dimensional numerical modelling of fluid-flow inside short tube orifices was performed, and successfully validated against a wide range of mass flow rate measurements reported for the refrigerant HFC-134a. Governing equations of continuity, momentum, energy and entropy were solved for describing the fluid flow under a wide variety of thermodynamic transitions (e.g., subcooled liquid region, metastable liquid region, metastable two-phase region and equilibrium two-phase region), including sudden contraction and enlargement. In this new study, a comprehensive comparison analysis between numerical simulation data and experimental measurements obtained for HFC-407C and HFC-410A refrigerants (N o  = 241) to extend the applicability of the same mathematical model was carried out. Using a widespread statistical analysis, based on weighted linear regressions with an outlier detection/rejection module at 95% of confidence level, the prediction performance of the mathematical model was again assessed. Linear regressions between predicted mass flow rate data and experimental measurements were computed, and used them as a statistical comparison criterion. A statistical comparison between predicted simulation results and mass flow rate experimental data are reported. Average deviation errors of ±11.1% (for the refrigerant HFC-407C) and ±7.3% (for refrigerant HFC-410A) were found between numerical model and experimental data. These results demonstrate a new and robust application of the model to predict reliably the mass flow rate through short tube orifices under metastable conditions, which enable this tool to be reliably used for the design of short tube orifices. - Highlights: •A modelling for evaluating short tube orifice was developed for refrigerant mixtures. •The numerical model applied considered metastable regions and choke flow. •The model was validated against experimental data for HFC-407C and HFC-410A. •Statistical analysis based

  16. The current status of mitigation, experience and repair regarding Alloy 600 issues on Japanese steam generator nozzles

    Hiro, T.; Okabe, T.; Inoue, T.

    2009-01-01

    One conspicuous problem seen in aged PWR plants is the PWSCC, which is considered to be caused by three factors, which are environment, material and stress. The degradation caused by PWSCC on high nickel content alloy (Alloy 600) at dissimilar material weld joints of steam generator nozzles has became conspicuous in Japan. This paper describes the mitigation technique used for the PWSCC, recent experiences on PWSCC issues and repair techniques implemented on Japanese steam generator nozzles with Alloy 600 weld. As a countermeasure against the PWSCC, ultrasonic shot peening (USP) was planned and conducted on the SG nozzles as a preventive maintenance in Japan. It has been confirmed that the stress near the inner surface can be converted into compressive stress by applying plastic strain to the surface using collision force of the shot material during the shot peening. USP employs the ultrasonic-wave vibration. The effects of this peening technique were confirmed by qualified test if there were undetectable cracks by ECT on the surface of the material. In Japan, there were 15 plants with SG nozzles which had Alloy 600 welds and these SG nozzles were inspected by ECT or VT as a confirmatory inspection before conducting the USP operation from 2006 to 2008. In these inspections, defects have been found at 19 hot nozzles in 8 plants. In addition, the defect in one of the plants has been found at the safe-end base metal made from stainless steel. In the root cause investigation result, it was confirmed that these cracks were typical PWSCC induced by high residual stress. These nozzles with defects were repaired by replacing the Alloy 600 welding material on surfaces exposed to primary water with the Alloy 690 welding material which has excellent PWSCC resistance. These material replacements were performed by cladding or replacement of nozzle safe end joint. These techniques are used not only to repair but also as a preventive maintenance. These mitigation or repair

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

    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.

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

    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 ...

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

    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.

  20. Combustor nozzle for a fuel-flexible combustion system

    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.

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

    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

  2. Finite element analysis of inclined nozzle-plate junctions

    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.)

  3. The German registry for natural orifice translumenal endoscopic surgery: report of the first 551 patients.

    Lehmann, Kai S; Ritz, Jörg P; Wibmer, Andreas; Gellert, Klaus; Zornig, Carsten; Burghardt, Jens; Büsing, Martin; Runkel, Norbert; Kohlhaw, Kay; Albrecht, Roland; Kirchner, Tom G; Arlt, Georg; Mall, Julian W; Butters, Michael; Bulian, Dirk R; Bretschneider, Jörgen; Holmer, Christoph; Buhr, Heinz J

    2010-08-01

    To analyze patient outcome in the first 14 months of the German natural orifice translumenal endoscopic surgery (NOTES) registry (GNR). NOTES is a new surgical concept, which permits scarless intra-abdominal operations through natural orifices, such as the mouth, vagina, rectum, or urethra. The GNR was established as a nationwide outcome database to allow the monitoring and safe introduction of this technique in Germany. The GNR was designed as a voluntary database with online access. All surgeons in Germany who performed NOTES procedures were requested to participate in the registry. The GNR recorded demographical and therapy data as well as data on the postoperative course. A total of 572 target organs were operated in 551 patients. Cholecystectomies accounted for 85.3% of all NOTES procedures. All procedures were performed in female patients using transvaginal hybrid technique. Complications occurred in 3.1% of all patients, conversions to laparoscopy or open surgery in 4.9%. In cholecystectomies, institutional case volume, obesity, and age had substantial effect on conversion rate, operation length, and length of hospital stay, but no effect on complications. Despite the fact that NOTES has just recently been introduced, the technique has already gained considerable clinical application. Transvaginal hybrid NOTES cholecystectomy is a practicable and safe alternative to laparoscopic resection even in obese or older patients.

  4. Disinfection of Escherichia coli bacteria using hybrid method of ozonation and hydrodynamic cavitation with orifice plate

    Karamah, Eva F.; Ghaudenson, Rioneli; Amalia, Fitri; Bismo, Setijo

    2017-11-01

    This research aims to evaluate the performance of hybrid method of ozonation and hydrodynamic cavitation with orifice plate on E.coli bacteria disinfection. In this research, ozone dose, circulation flowrate, and disinfection method were varied. Ozone was produced by commercial ozonator with ozone dose of 64.83 mg/hour, 108.18 mg/hour, and 135.04 mg/hour. Meanwhile, hydrodynamic cavitation was generated by an orifice plate. The disinfection method compared in this research were: hydrodynamic cavitation, ozonation, and the combination of both. The best result on each method was achieved on the 60th minutes and with a circulation flowrate of 7 L/min. The hybrid method attained final concentration of 0 CFU/mL from the initial concentration of 2.10 × 105 CFU/mL. The ozonation method attained final concentration of 0 CFU/mL from the initial concentration of 1.32 × 105 CFU/mL. Cavitation method gives the least disinfection with final concentration of 5.20 × 104 CFU/mL from the initial concentration of 2.17 × 105 CFU/mL. In conclusion, hybrid method gives a faster and better disinfection of E.coli than each method on its own.

  5. NOViSE: a virtual natural orifice transluminal endoscopic surgery simulator.

    Korzeniowski, Przemyslaw; Barrow, Alastair; Sodergren, Mikael H; Hald, Niels; Bello, Fernando

    2016-12-01

    Natural orifice transluminal endoscopic surgery (NOTES) is a novel technique in minimally invasive surgery whereby a flexible endoscope is inserted via a natural orifice to gain access to the abdominal cavity, leaving no external scars. This innovative use of flexible endoscopy creates many new challenges and is associated with a steep learning curve for clinicians. We developed NOViSE-the first force-feedback-enabled virtual reality simulator for NOTES training supporting a flexible endoscope. The haptic device is custom-built, and the behaviour of the virtual flexible endoscope is based on an established theoretical framework-the Cosserat theory of elastic rods. We present the application of NOViSE to the simulation of a hybrid trans-gastric cholecystectomy procedure. Preliminary results of face, content and construct validation have previously shown that NOViSE delivers the required level of realism for training of endoscopic manipulation skills specific to NOTES. VR simulation of NOTES procedures can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. In the context of an experimental technique, NOViSE could potentially facilitate NOTES development and contribute to its wider use by keeping practitioners up to date with this novel surgical technique. NOViSE is a first prototype, and the initial results indicate that it provides promising foundations for further development.

  6. Dual discharge from a stratified two-phase region through side orifices oriented horizontally

    Hassan, I G; Soliman, H M; Sims, G E [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Mechanical Engineering; Kowalski, J E [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

    1996-12-31

    Experimental data are presented for the mass flow rate and quality of two-phase (air-water) discharge from a stratified region through two side orifices (6.35 mm i.d.) with their parallel centre lines located in a horizontal plane. These data correspond to different values of the interface level between the onsets of gas and liquid entrainments for test-section pressures of 316 and 517 kPa, test-section-to-separators pressure difference ranging from 40 to 235 kPa, orifice separating distance to diameter ratio ranging from 1.5 to 8 and different hydraulic resistances of the lines connecting the test section to the separators. Influences of these independent variables on the deviation between the present results (of mass flow rate and quality) and those corresponding to a single discharge are presented and discussed. Normalized plots are presented showing that the present data of dual discharge and those of a single discharge can be collapsed for the whole test range when specific definition for the dimensionless height of the interface and mass flow rate are used. Excellent agreement is demonstrated between single-discharge correlations and the present data using these dimensionless quantities. (author). 12 refs., 1 tab., 16 figs.

  7. Laparoscopic sleeve gastrectomy for morbid obesity with natural orifice specimen extraction (NOSE).

    Gunkova, P; Gunka, I; Zonca, P; Dostalik, J; Ihnat, P

    2015-01-01

    An experience with laparoscopic sleeve gastrectomy using the natural orifice specimen extraction (NOSE) technique. Bariatric surgery is nowadays the only long term effective obesity treatment method. Twenty one consecutive patients underwent laparoscopic sleeve gastrectomy with the use of natural orifice specimen extraction (NOSE) in the Surgical Clinic of Faculty Hospital Ostrava between May 2012 and August 2012. Inclusion criteria were the body mass index (BMI) higher than 35 kg/m2 or higher than 32 kg/m2 accompanied with relevant comorbidities. Among 21 patients in this series, there were three men (14.3%) and 18 women (85.7%). Their mean age was 40.9±10.2 years. Their mean preoperative BMI was 40.4±4.6 kg/m2. No patient had previous bariatric surgery, one patient had laparoscopic fundoplication. All operations were completed laparoscopically with no conversions to an open procedure. In two cases, laparoscopic cholecystectomy was performed and the gallbladder was extracted along with the gastric specimen by transgastric approach. Laparoscopic sleeve gastrectomy is a safe and effective bariatric procedure with low morbidity and mortality. Based on our initial experiences it could be an indication for NOSE with transgastric approach. Obese patients would benefit from this approach due to the elimination of wound complications (Tab. 2, Fig. 3, Ref. 22).

  8. Dual discharge from a stratified two-phase region through side orifices oriented horizontally

    Hassan, I.G.; Soliman, H.M.; Sims, G.E.; Kowalski, J.E.

    1995-01-01

    Experimental data are presented for the mass flow rate and quality of two-phase (air-water) discharge from a stratified region through two side orifices (6.35 mm i.d.) with their parallel centre lines located in a horizontal plane. These data correspond to different values of the interface level between the onsets of gas and liquid entrainments for test-section pressures of 316 and 517 kPa, test-section-to-separators pressure difference ranging from 40 to 235 kPa, orifice separating distance to diameter ratio ranging from 1.5 to 8 and different hydraulic resistances of the lines connecting the test section to the separators. Influences of these independent variables on the deviation between the present results (of mass flow rate and quality) and those corresponding to a single discharge are presented and discussed. Normalized plots are presented showing that the present data of dual discharge and those of a single discharge can be collapsed for the whole test range when specific definition for the dimensionless height of the interface and mass flow rate are used. Excellent agreement is demonstrated between single-discharge correlations and the present data using these dimensionless quantities. (author). 12 refs., 1 tab., 16 figs

  9. Experimental study of cooling performance of pneumatic synthetic jet with singular slot rectangular orifice

    Yu, Roger Ho Zhen; Ismail, Mohd Azmi bin; Ramdan, Muhammad Iftishah; Mustaffa, Nur Musfirah binti

    2017-03-01

    Synthetic Jet generates turbulence flow in cooling the microelectronic devices. In this paper, the experiment investigation of the cooling performance of pneumatic synthetic jet with single slot rectangular orifices at low frequency motion is presented. The velocity profile at the end of the orifice was measured and used as characteristic performance of synthetic jet in the present study. Frequencies of synthetic jet and the compressed air pressure supplied to the pneumatic cylinder (1bar to 5bar) were the parameters of the flow measurement. The air velocity of the synthetic jet was measured by using anemometer air flow meter. The maximum air velocity was 0.5 m/s and it occurred at frequency motion of 8 Hz. The optimum compressed air supplied pressure of the synthetic jet study was 4 bar. The cooling performance of synthetic jet at several driven frequencies from 0 Hz to 8 Hz and heat dissipation between 2.5W and 9W were also investigate in the present study. The results showed that the Nusselt number increased and thermal resistance decreased with both frequency and Reynolds number. The lowest thermal resistance was 5.25°C/W and the highest Nusselt number was 13.39 at heat dissipation of 9W and driven frequency of 8Hz.

  10. Two cases of laparoscopic total colectomy with natural orifice specimen extraction and review of the literature.

    Gundogan, Ersin; Aktas, Aydin; Kayaalp, Cuneyt; Gonultas, Fatih; Sumer, Fatih

    2017-09-01

    We present two cases of natural orifice specimen extraction (NOSE) after laparoscopic total colectomy and ileorectal anastomosis (TC-IRA), and we also review all of the previously reported cases. Our aim was to focus on patient selection for NOSE after TC-IRA. The PubMed and Google Scholar databases were scanned. Demographic features, surgical indications, and techniques were analyzed. Basic calculations were used for statistical analysis. A total of 13 cases were detected in addition to our 2 cases. All of the specimens were removed through the natural orifices successfully. No case required a diverting ileostomy. No patients were converted to open surgery or to conventional laparoscopy. Complications were reported in three patients. Transanal extractions were performed in 12 cases (10 colonic inertia, 2 polyposis), and transvaginal extractions were performed in 3 cases (2 malignancy, 1 colonic inertia). Both transanal and transvaginal specimen extractions after laparoscopic TC-IRA can be preferred. However, transanal extraction seems to be feasible in cases of TC for benign disease with a limited mesenteric-omental resection. If the indication is a malignancy requiring a mesenteric-omental resection, a transvaginal route should be preferred for a voluminous specimen.

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

    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

  12. Flow resistance of orifices and spacers of BWR thermal-hydraulic and neutronic coupling loop

    Iguchi, Tadashi; Asaka, Hideaki; Nakamura, Hideo

    2002-03-01

    Authors are performing THYNC experiments to study thermal-hydraulic instability under neutronic and thermal-hydraulic coupling. In THYNC experiments, the orifices are installed at the exit of the test section and the spacers are installed in the test section, in order to properly simulate in-core thermal-hydraulics in the reactor core. It is necessary to know the flow resistance of the orifices and spacers for the analysis of THYNC experimental results. Consequently, authors measured the flow resistance of orifice and spacer under single-phase and two-phase flows. Using the experimental results, authors investigated the dependency of the flow resistances on the parameters, such as pressure, mass flux, an geometries. Furthermore, authors investigated the applicability of the basic two-phase flow models, for example the separate flow model, to the two-phase flow multiplier. As the result of the investigation on the single-phase flow experiment, it was found (1) that the effects of pressure and mass flux flow resistance are described by a function of Reynolds number, and (2) that flow resistances of the orifice and the spacer are calculated with the previous prediction methods. However, it was necessary to introduce an empirical coefficient, since it was difficult to predict accurately the flow resistance only with the previous prediction method due to the complicated geometry dependency, for example a flow area blockage ratio. On the other hand, according to the investigation on two-phase flow experiment, the followings were found. (1) Relation between the two-phase flow multiplier and the quality is regarded to be linear under pressure of 2MPa - 7MPa. The relation is dependent on pressure and geometry, and is little dependent on mass flux. (2) Relation between the two-phase flow multiplier and void fraction is little dependent on pressure, mass flux, and geometry under pressure of 0.2MPa - 7MPa and void fraction less than 0.6. The relation is less dependent on

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

    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.

  14. CAN-DO, CFD-based Aerodynamic Nozzle Design and Optimization program for supersonic/hypersonic wind tunnels

    Korte, John J.; Kumar, Ajay; Singh, D. J.; White, J. A.

    1992-01-01

    A design program is developed which incorporates a modern approach to the design of supersonic/hypersonic wind-tunnel nozzles. The approach is obtained by the coupling of computational fluid dynamics (CFD) with design optimization. The program can be used to design a 2D or axisymmetric, supersonic or hypersonic, wind-tunnel nozzles that can be modeled with a calorically perfect gas. The nozzle design is obtained by solving a nonlinear least-squares optimization problem (LSOP). The LSOP is solved using an iterative procedure which requires intermediate flowfield solutions. The nozzle flowfield is simulated by solving the Navier-Stokes equations for the subsonic and transonic flow regions and the parabolized Navier-Stokes equations for the supersonic flow regions. The advantages of this method are that the design is based on the solution of the viscous equations eliminating the need to make separate corrections to a design contour, and the flexibility of applying the procedure to different types of nozzle design problems.

  15. [Urethroplasty with transection of urethral orifice and preservation and lengthening of urethral plate: highly applicable to the treatment of hypospadias].

    Wang, Wen-Min; Qiu, Wei-Feng; Qian, Chong

    2010-07-01

    To explore the feasibility of urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate in the treatment of hypospadias. Forty-eight patients with hypospadias (18 of the coronal type, 21 the penile type, 8 the penoscrotal type and 1 the perineal type) underwent urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate. The surgical effects were observed by following up the patients for 3-27 months. One-stage surgical success was achieved in 44 of the cases, with satisfactory functional and cosmetic results but no complications. Two cases developed urinary fistula and another 2 urethral stricture, but all cured by the second surgery. Urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate is a simple, safe and effective surgical procedure for the treatment of hypospadias.

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

    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.

  17. Pitot pressure measurements in flow fields behind circular-arc nozzles with exhaust jets at subsonic free-stream Mach numbers. [langley 16 foot transonic tunnel

    Mason, M. L.; Putnam, L. E.

    1979-01-01

    The flow field behind a circular arc nozzle with exhaust jet was studied at subsonic free stream Mach numbers. A conical probe was used to measure the pitot pressure in the jet and free stream regions. Pressure data were recorded for two nozzle configurations at nozzle pressure ratios of 2.0, 2.9, and 5.0. At each set of test conditions, the probe was traversed from the jet center line into the free stream region at seven data acquisition stations. The survey began at the nozzle exit and extended downstream at intervals. The pitot pressure data may be applied to the evaluation of computational flow field models, as illustrated by a comparison of the flow field data with results of inviscid jet plume theory.

  18. PULSED MOLECULAR BEAM PRODUCTION WITH NOZZLES

    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)

  19. Specific decontamination methods: water nozzle, cavitation erosion

    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

  20. Feedback mechanism for smart nozzles and nebulizers

    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.

  1. Noise Prediction Module for Offset Stream Nozzles

    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.

  2. An Automated DAKOTA and VULCAN-CFD Framework with Application to Supersonic Facility Nozzle Flowpath Optimization

    Axdahl, Erik L.

    2015-01-01

    Removing human interaction from design processes by using automation may lead to gains in both productivity and design precision. This memorandum describes efforts to incorporate high fidelity numerical analysis tools into an automated framework and applying that framework to applications of practical interest. The purpose of this effort was to integrate VULCAN-CFD into an automated, DAKOTA-enabled framework with a proof-of-concept application being the optimization of supersonic test facility nozzles. It was shown that the optimization framework could be deployed on a high performance computing cluster with the flow of information handled effectively to guide the optimization process. Furthermore, the application of the framework to supersonic test facility nozzle flowpath design and optimization was demonstrated using multiple optimization algorithms.

  3. PIV Measurements of Chevrons on F400 Tactical Aircraft Nozzle Model

    Bridges, James; Wernet, Mark; Frate, Franco

    2010-01-01

    Previous talks at this meeting have covered our collaborative work on high-energy jets such as present in tactical aircraft (those with supersonic plumes). The emphasis of this work is improving our understanding of flow physics and our prediction tools. In this presentation we will discuss recent flow diagnostics acquired using Particle Image Velocimetry (PIV) made on an underexpanded shocked jet plume from a tactical aircraft nozzle. In this presentation we show cross-sectional and streamwise cuts of both mean and turbulent velocities of an F404 engine nozzle with various chevron designs applied. The impact of chevron penetration, length, and width are documented. The impact of the parameters is generally nonlinear in measures considered here, a surprising result given the relatively smooth behavior of the noise to variations in these chevron parameters.

  4. Magnetic-Laval-Nozzle Effect on a Magneto-Plasma-Dynamic Arcjet

    Inutake, Masaaki; Miyazaki, Hiroyuki; Yoshino, Kyohei; Tobari, Hiroyuki; Hattori, Kunihiko; Ando, Akira

    2003-01-01

    A magneto-plasma-dynamic arcjet (MPDA) is one of the promising candidates for a manned interplanetary space thruster with a higher specific impulse and larger thrust. An MPDA with an externally-applied magnetic nozzle is investigated to improve the thrust efficiency. From spectroscopic measurements of the MPDA plasma, it is found that with the increase in the discharge current not only the flow velocity but also the ion temperature increase near the muzzle of the MPDA with a uniform axial magnetic field and so the ion acoustic Mach number is limited to a value less than unity. By installing a Laval-type magnetic nozzle near the muzzle of the MPDA, the subsonic flow is successfully accelerated to a supersonic one by converting the ion thermal energy to the flow energy. The results are compared with the prediction by a1-D isentropic flow model

  5. Indirect Combustion Noise: Noise Generation by Accelerated Vorticity in a Nozzle Flow

    Nancy Kings

    2010-09-01

    Full Text Available The noise generation by accelerated vorticity waves in a nozzle flow was investigated in a model experiment. This noise generation mechanism belongs, besides entropy noise, to the indirect combustion noise phenomena. Vorticity as well as entropy fluctuations, originating from the highly turbulent combustion zone, are convected with the flow and produce noise during their acceleration in the outlet nozzle of the combustion chamber. In the model experiment, noise generation of accelerated vorticity fluctuations was achieved. The vorticity fluctuations in the tube flow were produced by injecting temporally additional air into the mean flow. As the next step, a parametric study was conducted to determine the major dependencies of the so called vortex noise. A quadratic dependency of the vortex noise on the injected air amount was found. In order to visualise and classify the artificially generated vorticity structures, planar velocity measurements have been conducted applying Particle Image Velocimetry (PIV.

  6. Impact of valve prosthesis-patient mismatch estimated by echocardiographic-determined effective orifice area on long-term outcome after aortic valve replacement.

    Florath, Ines; Albert, Alexander; Rosendahl, Ulrich; Ennker, Ina Carolin; Ennker, Jrgen

    2008-06-01

    The impact of valve prosthesis-patient mismatch on long-term outcome after aortic valve replacement estimated by various variables such as projected indexed effective orifice area and internal geometric orifice area obtained from in vivo or in vitro published data is still controversial. The effective orifice area was measured by echocardiography in 533 patients. The mean age of the patients was 71 +/- 9 years; mean follow-up time was 4.7 +/- 2.2 years. The impact of severe (indexed effective orifice area regression. Severe mismatch (hazard ratio: 1.9 [1.08-3.21]) was a significant predictor of survival time after adjustment for age, left ventricular ejection fraction, atrial fibrillation, New York Heart Association class, serum creatinine, and hemoglobin level. The 5- and 7-year survival rates were 71% +/- 4% and 54% +/- 8% for patients with severe mismatch and 83% +/- 4% and 80% +/- 8% for patients with mild mismatch, respectively. The correlation between projected and measured indexed effective orifice area was of medium strength (r = 0.49), and the frequency of observed mismatch depended linearly on the projected indexed effective orifice area. Although projected indexed effective orifice area and indexed internal geometric orifice area were significant predictors of severe mismatch, the sensitivity and specificity for severe prosthesis-patient mismatch were only 75% and 52%, using an optimal threshold of projected indexed effective orifice area defined by the Youden index. Severe prosthesis-patient mismatch estimated by effective orifice area measured within 10 days was an independent risk factor of survival time. Projected indexed effective orifice area determined at surgery does not sufficiently predict mismatch.

  7. A review on the status of natural orifice transluminal endoscopic surgery (NOTES cholecystectomy: techniques and challenges

    Michael C Meadows

    2010-09-01

    Full Text Available Michael C Meadows1,3, Ronald S Chamberlain1,2,31Department of Surgery, Saint Barnabas Medical Center, Livingston, NJ, USA; 2Department of Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA; 3Saint George’s University, School of Medicine, West Indies, GrenadaIntroduction: The evolution of techniques for the performance of a cholecystectomy over the last 25 years has been swift. The laparoscopic approach is now the gold standard for removal of the gall bladder and is the most frequently performed minimally invasive procedure globally. Currently in its infancy stage, natural orifice transluminal endoscopy surgery, or NOTES, is purported to be the next leap forward in minimally invasive approaches. The safety, feasibility, and effectiveness of this procedure, as well as the significance of potential benefits to patients beyond current surgical approaches are yet undetermined.Methods: A comprehensive literature search was conducted using PubMed, a search engine ­created by the National Library of Medicine. Keywords used in the search included “natural orifice transluminal endoscopic surgery”, “NOTES”, “cholecystectomy”, “transcolonic”, “transvaginal”, and “transgastric”. The accumulated literature was critically analyzed and reviewed.Results: One-hundred and eighty-six cases of NOTES cholecystectomies have been published to date. Of these, 174 have been performed through a transvaginal approach. The remainder of the procedures were performed transgastrically. There are no published reports of ­transcolonic cholecystectomies performed in humans. Four of 186 cases (2.15% were converted to traditional laparoscopy due to intraoperative complications. No significant complications or mortalities have been reported.Conclusion: NOTES cholecystectomy appears to be a feasible procedure. However, technical, safety, and ethical issues remain relatively unresolved. Besides improved cosmesis, whether additional

  8. Flame Interactions and Thermoacoustics in Multiple-Nozzle Combustors

    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

  9. Fuel injector nozzle for an internal combustion engine

    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.

  10. The fabrication of nozzles for nuclear components by welding

    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

  11. Fabrication and Application of Mono-sized Spherical Micro Particles by Pulsated Orifice Ejection Method

    DONG Wei

    2018-02-01

    Full Text Available A novel technology called pulsated orifice ejection method(POEM and used for preparing mono-sized and high-precision spherical micro particles was introduced in this article. The working principle of the technique was illustrated and it was in two modes:low-melting point diaphragm mode and high-melting point rod mode, depending on the different melting points of materials. The particles prepared by POEM have the advantages of mono-sized, uniform and controllable particle size, high sphericity, and consistent thermal history. By introducing the application of particles prepared by this method, showing the huge application prospects of this technology in electronic packaging, bioengineering, micro-fabrication, rapid solidification analysis of metal droplets, additive manufacturing and so on.With the development of POEM, this technology is predicted to have wider prospects due to its unique characteristics.

  12. Restenosis after stenting in symptomatic vertebral arterial orifice disease and considerations for better outcome

    Chang, Jun Young; Park, Hyun; Kwon, Oki

    2017-01-01

    We have performed stenting in 11 patients with symptomatic vertebral arterial orifice stenosis refractory to medical treatment or impairment in anterior circulation. Three of the 11 patients experienced asymptomatic severe in-stent restenosis or occlusion. Bare metal stents were used in those three patients, two of whom received revascularization therapy. Development of sufficient cervical collateral channels reconstituting the distal vertebral artery was the common feature in patients with asymptomatic in-stent restenosis. In selecting appropriate stents, consideration of mechanical strength and drug-eluting properties of a stent according to characteristics of the target vessel is important to reduce the risk of in-stent restenosis. Any decision to perform revascularization should be based on the presence of abundant cervical collaterals as well as clinical symptoms of vertebrobasilar ischemia. PMID:28304206

  13. Evaluation of effective regurgitant orifice area of mitral valvular regurgitation by multislice cardiac computed tomography

    Vural, M.; Ucar, O.; Celebi, O.O.; Cicekcioglu, H.; Durmaz, H.A.; Selvi, N.A.; Koparal, S.; Aydogdu, S.

    2010-01-01

    The purpose of our study was to assess the diagnostic accuracy of multislice computed tomography (MSCT) for the identification and quantification of mitral valve regurgitation in comparison with transthoracic echocardiography (TTE). Twenty-six patients (15 females, 11 males with a mean age of 44.6±14.1 years) who were in follow-up with the diagnosis of mitral regurgitation and those who were referred for MSCT were enrolled. MSCT results were compared with TTE measurements. The mean effective mitral regurgitant orifice area at MSCT was 23.1±13.0 mm 2 and at echocardiography was 24.4±16.0mm 2 . Bland-Altman analysis showed good agreement between the two imaging methods. MSCT provides reliable and good results for the evaluation of mitral regurgitation. (author)

  14. A mathematical model for erosion-corrosion downstream of an orifice

    Thomas, R.M.

    1989-08-01

    In certain types of nuclear plant, the internal surfaces of the steel high-pressure boiler tubes become covered with magnetite. This normal growth of protective magnetite may, in unfavourable circumstances, be replaced by rapid attack on the tube wall. Particularly at risk are the regions downstream of the orifice plates commonly fitted near the boiler inlet. An attempt is made to construct a mathematical model for this erosion-corrosion which is considerably more complete than those available hitherto. A systematic synthesis is developed of the various aspects of the phenomenon, namely the mechanism of the topotactic oxidation at the interface between magnetite and metal, the kinetics of the electrode reactions at the magnetite/solution interface, the thermodynamics of magnetite solubility and the calculation of mass transfer in solution. With one choice of parameters and some simplification, the treatment reduces to the original theory of Bignold. (author)

  15. The counter-current flooding limit in vertical tubes with and without orifices

    Tye, P.; Davidson, M.; Teyssedou, A.; Tapucu, A.; Matuszkiewicz, A.; Midvidy, W.

    1993-01-01

    For hypothetical loss of coolant accidents in nuclear reactors, rapid reflooding of the core is desirable. In CANDU reactors the cooling water is injected into the headers which are connected to the fuel channels by the feeder pipes. These pipes consist of vertical and horizontal runs; in some feeders, orifices and/or venturi flow meters are installed for flow adjustments and measurements respectively. For certain postulated accident scenarios, steam coming from the fuel channels and/or generated in the hot feeders may flow in the direction opposite to that of the cooling water thereby, creating a vertical or horizontal counter-current two-phase flow. Under these conditions, the rate at which cooling water can enter the fuel channels may be limited by the flooding phenomena. This phenomena is greatly affected by the geometry of the feeder pips, shape and number of fittings, and the flow area restrictions located in the feeders. In this paper the influence that orifice type flow area restrictions have on the counter-current flooding limit (CCFL) in a vertical tube is examined. air and water at close to atmospheric conditions are used as the working fluids. The data collected on the counter-current flooding limit in a vertical tube both with and without flow area restrictions is compared against some of the most commonly used correlations that are available in the open literature. Data on the two-phase counter-current pressure drop below the flooding point are also presented. 12 refs., 10 figs., 1 tab

  16. Influence of spray nozzles and adjuvants in drift reduction potential in wind tunnel
    Influência de pontas de pulverização e adjuvantes no potencial de redução de deriva em túnel de vento

    Rodolfo Glauber Chechetto; Ulisses Rocha Antuniassi; Alisson Augusto Barbieri Mota; Fernando Kassis Carvalho; Anne Caroline Arruda e Silva; Caroline Michels Vilela

    2013-01-01

    The drift is intimately linked to inappropriate use of pesticides and an important factor for reducing it, is the correct selection of spray nozzles and adjuvants. The objective of this work was to evaluate the drift potential in wind tunnel with different spray nozzles and different concentrations of adjuvants. The experiment was composed by six spray solutions (vegetable oil (in three concentrations), mineral oil, surfactant and reducing drift), which were applied with two nozzles, one pre-...

  17. Continuous synthesis of tert.-butyl peroxypivalate using a single channel micro reactor equipped with orifices as emulsification units

    Illg, T.; Hessel, V.; Löb, P.; Schouten, J.C.

    2011-01-01

    The two-step synthesis of tert-butyl peroxypivalate is performed in a single-channel microreactor. The first step, the deprotonation of tert-butyl hydroperoxide, is done in a simple mixer tube setup. The residence time section for the second reaction step is equipped with orifices for interfacial

  18. Shear flow over a plane wall with an axisymmetric cavity or a circular orifice of finite thickness

    Pozrikidis, C.

    1994-01-01

    Shear flow over a plane wall that contains an axisymmetric depression or pore is studied using a new boundary integral method which is suitable for computing three-dimensional Stokes flow within axisymmetric domains. Numerical results are presented for cavities in the shape of a section of a sphere or a circular cylinder of finite length, and for a family of pores or orifices with finite thickness. The results illustrate the distribution of shear stresses over the plane wall and inside the cavities or pores. It is found that in most cases, the distribution of shear stresses over the plane wall, around the depressions, is well approximated with that for flow over an orifice of infinitesimal thickness for which an exact solution is available. The kinematic structure of the flow is discussed with reference to eddy formation and three-dimensional flow reversal. It is shown that the thickness of a circular orifice or depth of a pore play an important role in determining the kinematical structure of the flow underneath the orifice in the lower half-space

  19. Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber

    Guerra, V.G.; Goncalves, J.A.S. [Department of Chemical Engineering, Federal University of Sao Carlos, Via Washington Luiz, Km. 235, 13565-905 Sao Carlos, SP (Brazil); Coury, J.R. [Department of Chemical Engineering, Federal University of Sao Carlos, Via Washington Luiz, Km. 235, 13565-905 Sao Carlos, SP (Brazil)], E-mail: jcoury@ufscar.br

    2009-01-15

    Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

  20. Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber

    Guerra, V.G.; Goncalves, J.A.S.; Coury, J.R.

    2009-01-01

    Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets

  1. Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber.

    Guerra, V G; Gonçalves, J A S; Coury, J R

    2009-01-15

    Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

  2. Appendiceal Abscesses Reduced in Size by Drainage of Pus from the Appendiceal Orifice during Colonoscopy: A Report of Three Cases

    Shinjiro Kobayashi

    2014-11-01

    Full Text Available Interval appendectomy (IA for appendiceal abscesses is useful for avoiding extended surgery and preventing postoperative complications. However, IA has problems in that it takes time before an abscess is reduced in size in some cases and in that elective surgery may result in a delay in treatment in patients with a malignant tumor of the appendix. In order to rule out malignancy, we performed colonoscopy on three patients with an appendiceal abscess that did not decrease in size 5 or more days after IA. After malignancy had been ruled out by examination of the area of the appendiceal orifice, the appendiceal orifice was compressed with a colonoscope, and a catheter was inserted through the orifice. Then, drainage of pus was observed from the appendiceal orifice into the cecal lumen. Computed tomography performed 3 days after colonoscopy revealed a marked reduction in abscess size in all patients. No endoscopy-related complication was noted. Colonoscopy in patients with an appendiceal abscess may not only differentiate malignant tumors, but also accelerate reduction in abscess size.

  3. Simplified one-orifice venoplasty for middle hepatic vein reconstruction in adult living donor liver transplantation using right lobe grafts.

    Kim, Joo Dong; Choi, Dong Lak; Han, Young Seok

    2014-05-01

    Middle hepatic vein (MHV) reconstruction is often essential to avoid hepatic congestion and serious graft dysfunction in living donor liver transplantation (LDLT). The aim of this report was to introduce evolution of our MHV reconstruction technique and excellent outcomes of simplified one-orifice venoplasty. We compared clinical outcomes with two reconstruction techniques through retrospective review of 95 recipients who underwent LDLT using right lobe grafts at our institution from January 2008 to April 2012; group 1 received separate outflow reconstruction and group 2 received new one-orifice technique. The early patency rates of MHV in group 2 were higher than those in group 1; 98.4% vs. 88.2% on postoperative day 7 (p = 0.054) and 96.7% vs. 82.4% on postoperative day 14, respectively (p = 0.023). Right hepatic vein (RHV) stenosis developed in three cases in group 1, but no RHV stenosis developed because we adopted one-orifice technique (p = 0.043). The levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in group 2 were significantly lower than those in group 1 during the early post-transplant period. In conclusion, our simplified one-orifice venoplasty technique could secure venous outflow and improve graft function during right lobe LDLT. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Pure natural orifice transluminal endoscopic surgery (NOTES) with ultrasonography-guided transgastric access and over-the-scope-clip closure

    Donatsky, Anders Meller; Andersen, Luise; Nielsen, Ole Lerberg

    2012-01-01

    Most natural orifice transluminal endoscopic surgery (NOTES) procedures to date rely on the hybrid technique with simultaneous laparoscopic access to protect against access-related complications and to achieve adequate triangulation for dissection. This is done at the cost of the potential benefi...

  5. New intraocular pressure measurement method using reflected pneumatic pressure from cornea deformed by air puff of ring-type nozzle.

    Kim, Hyung Jin; Seo, Yeong Ho; Kim, Byeong Hee

    2017-01-01

    In this study, a non-contact type intraocular pressure (IOP) measuring system using reflected pneumatic pressure is proposed to overcome the disadvantages of existing measurement systems. A ring-type nozzle, a key component in the proposed system, is designed via computational fluid analysis. It predicts the reflected pneumatic pressure based on the nozzle exit angle and inner and outer diameters of the nozzle, which are 30°, 7 mm, and 9 mm, respectively. Performance evaluation is conducted using artificial eyes fabricated using polydimethylsiloxane with the specifications of human eyes. The IOP of the fabricated artificial eyes is adjusted to 10, 30, and 50 mm Hg, and the reflected pneumatic pressure is measured as a function of the distance between the ring-type nozzle and artificial eye. The measured reflected pneumatic pressure is high when the measurement distance is short and eye pressure is low. The cornea of an artificial eye is significantly deformed at a low IOP, and the applied pneumatic pressure is more concentrated in front of the ring-type nozzle because of the deformed cornea. Thus, the reflected pneumatic pressure at a low IOP has more inflows into the pressure sensor inserted inside the nozzle. The sensitivity of the output based on the IOP at measurement distances between 3-5 mm is -0.0027, -0.0022, -0.0018, -0.0015, and -0.0012. Sensitivity decreases as the measurement distance increases. In addition, the reflected pneumatic pressure owing to the misalignment at the measurement distances of 3-5 mm is not affected within a range of 0.5 mm. Therefore, the measurement range is acceptable up to a 1 mm diameter from the center of an artificial eye. However, the accuracy gradually decreases as the reflected pneumatic pressure from a misalignment of 1 mm or more decreases by 26% or more.

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

    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.

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

    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...

  8. Design methods of Coanda effect nozzle with two streams

    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.

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

    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

  10. Characterization of Plasmadynamics within a Small Magnetic Nozzle

    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...

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

    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)

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

    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...

  13. Residual Stress Evaluation of Weld Inlay Process on Reactor Vessel Nozzles

    Cho, Kihyun; Cho, Hong Seok [KEPCO KPS, Naju (Korea, Republic of)

    2015-10-15

    Weld overlay, weld inlay and stress improvement are mitigation technologies for butt joints. Weld overlay is done on pressurizer nozzles which are the highest potential locations occurring PWSCC due to high temperature in Korea. Reactor vessel nozzles are other big safety concerns for butt joints. Weld overlay and stress improvement should be so difficult to apply to those locations because space is too limited. Weld inlay should be one of the solutions. KEPCO KPS has developed laser welding system and process for reactor nozzles. Welding residual stress analysis is necessary for flaw evaluation. United States nuclear regulatory commission has calculated GTAW(Gas Tungsten Arc Welding) residual stress using ABAQUS. To confirm effectiveness of weld inlay process, welding residual stress analysis was performed. and difference between GTAW and LASER welding process was compared. Evaluation of weld inlay process using ANSYS and ABAQUS is performed. All of the both results are similar. The residual stress generated after weld inlay was on range of 450-500 MPa. Welding residual stresses are differently generated by GTAW and LASER welding. But regardless of welding process type, residual tensile stress is generated on inside surface.

  14. 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

    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.

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

    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

  16. Top Nozzle Holddown Spring Optimization of KSNP Fuel Assembly

    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

  17. Removable top nozzle and tool for a nuclear reactor fuel assembly

    Wilson, J.F.; Cerni, S.; Gjertsen, R.K.

    1986-01-01

    A fuel assembly is described for a nuclear reactor including a bottom nozzle, at least one longitudinally extending control rod guide thimble having an upper end and a lower end being attached to the bottom nozzle and projecting upwardly therefrom, transverse grids axially spaced along-the thimble for supporting an array of upstanding fuel rods, and a top nozzle subassembly removable mounted on the upper end of the guide thimble for obtaining top access to the fuel rods upon removal thereof. The top nozzle subassembly consists of: (a) a section integrally formed on the upper end of the guide thimble and having external threads thereon; (b) a lower adapter plate having a guide thimble hole for receiving the guide thimble so as to mount the adapter plate on the guide thimble for slidable movement therealong; (c) a retainer mounted on the guide thimble for restably supporting and limiting the downward movement of the adapter plate along the guide thimble; (d) an upper hold-down plate having a guide thimble passageway with an internal ledge for receiving the thimble so as to mount the hold-down plate on the thimble for slidable movement therealong; (e) spring means interposed between the upper hold-down plate and the lower adapter plate for biasing the hold-down plate upwardly when a downward force is applied thereon whereby the downward force is yieldably transmitted to the fuel assembly; and (f) a collar disposed within the passageway and in abutment with the ledge, the collar having an internal threaded section engageable with the externally threaded section to move the hold-down plate down against the spring means and thereby mounting of the subassembly on the guide thimble

  18. Nozzle Mounting Method Optimization Based on Robot Kinematic Analysis

    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.

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

    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

  20. Effect of nozzle arrangement on Venturi scrubber performance

    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.

  1. Reverse flow through a large scale multichannel nozzle

    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

  2. Jet Noise Scaling in Dual Stream Nozzles

    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.

  3. Elliptic nozzle aspect ratio effect on controlled jet propagation

    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)

  4. Elliptic nozzle aspect ratio effect on controlled jet propagation

    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)

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

    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.

  6. Effects of Nozzle Diameter on Diesel Spray Flames: A numerical study using an Eulerian Stochastic Field Method

    Pang, Kar Mun; Jangi, Mehdi; Bai, Xue-Song

    2017-01-01

    The present numerical study aims to assess the performance of an Eulerian Stochastic Field (ESF) model in simulating spray flames produced by three fuel injectors with different nozzle diameters of 100 μm, 180 μm and 363 μm. A comparison to the measurements shows that although the simulated ignit...... serve as an important tool for the simulation of spray flames in marine diesel engines, where fuel injectors with different nozzle diameters are applied for pilot and main injections.......The present numerical study aims to assess the performance of an Eulerian Stochastic Field (ESF) model in simulating spray flames produced by three fuel injectors with different nozzle diameters of 100 μm, 180 μm and 363 μm. A comparison to the measurements shows that although the simulated...... ignition delay times are consistently overestimated, the relative differences remain below 28%. Furthermore, the change of the averaged pressure rise with respect to the variation of nozzle diameter is captured by the model. The simulated flame lift-off lengths also agree with the measurements...

  7. Urethral orifice hyaluronic acid injections: a novel animal model of bladder outlet obstruction.

    Wang, Yongquan; Xiong, Zhiyong; Gong, Wei; Zhou, Zhansong; Lu, Gensheng

    2015-02-21

    We produced a novel model of bladder outlet obstruction (BOO) by periurethral injection of hyaluronic acid and compared the cystometric features, postoperative complications, and histopathological changes of that model with that of traditional open surgery. Forty female Sprague-Dawley rats were divided into three groups. Fifteen rats were subcutaneously injected with 0.2 ml hyaluronic acid at 5, 7, and 12 o'clock around the urethral orifice. Another fifteen rats underwent traditional open partial proximal urethral obstruction surgery, and 10 normal rats used as controls. After 4 weeks, filling cystometry, postoperative complications, and histopathological features were evaluated in each group. Three rats were also observed for 12 weeks after hyaluronic acid injection to evaluate the long-term effect. Hyaluronic acid periurethral injection caused increased maximum cystometric capacity, maximum bladder pressure, micturition interval, and post-void residual urine volume compared with control (p injection group had significantly shorter operative time, less incidence of incision infection and bladder stone formation compared with the surgery group (p injection and surgery bladders; these were not observed in the control group. Bladder weight and thickness of smooth muscle in the injection and surgery groups were significantly greater than those in the control group (p injection or control groups. Rats periurethrally injected hyaluronic acid were stable the compound was not fully absorbed in any rat after 12 weeks. Hyaluronic acid periurethral injection generates a simple, effective, and persistent animal model of BOO with lower complications, compared with traditional surgery.

  8. THE PERFORMANCE ANALYSIS OF A PACKED COLUMN : CALIBRATION OF AN ORIFICE

    Aynur ŞENOL

    2003-01-01

    Full Text Available Investigations to develop data for this study were made using a pilot scale glass column of 9 cm inside diameter randomly filled to a depth of 1.90 cm with a Raschig type ring at a slightly modified geometry. The geometrical characteristics of packing are: the total area of a single particle ad = 2.3 cm2; specific area ap = 10.37 cm2/cm3; voidage ? = 0.545 m3/m3. The efficiency tests were run using trichloroethylene/n-heptane system under total reflux conditions. Using the modified versions of the Eckert flooding model and the Bravo effective area (ae approach, as well as the Onda wetted area (aw and individual mass transfer coefficient models, it has been attempted to estimate the packing efficiency theoretically. This article also deals with the design strategies attributed to a randomly packed column. Emphasis is mainly placed on the way to formulate an algorithm of designing a pilot scale column through the models being attributed to the film theory. Using the column dry pressure drop properties based on the air flowing it has been achieved a generalized flow rate approach for calibrating of an orifice through which the air passes.

  9. Oxide deposition in the orifices of AGR boiler inlet ferrule assemblies

    Thomas, D.M.

    1988-08-01

    In experiments designed to study the erosion-corrosion behaviour of AGR boiler inlet ferrules using the CERL high velocity circulating isothermal water rig, oxide deposition was frequently found within the flow control orifices. The present investigation was carried out as a preliminary to a programme of experiments addressed specifically to this problem. Analysis shows the deposits to be predominantly magnetite (or possible maghemite) with traces of α-haematite. Calculations indicate that the maximum rate of magnetite deposition is mass transfer limited, although in some experiments no deposition occurred in cases where mass transfer would have allowed substantial deposition. Thus the occurrence of deposition is thought to depend on the rig potential as this varies with experimental conditions. In these experiments the surface potential is not found to be governed by the hydrogen level. Metallographic cross-sections through the ferrule control bores show the deposits to be found in regions of separated flow, and the flow markings in the deposits show that the flow is turbulent in these zones. The exact morphology is thought to be influenced by machining marks within the control bore. (author)

  10. Complications of transvaginal natural orifice transluminal endoscopic surgery: a series of 102 patients.

    Wood, Stephanie G; Panait, Lucian; Duffy, Andrew J; Bell, Robert L; Roberts, Kurt E

    2014-04-01

    To review the complications encountered in our facility and in previously published studies of transvaginal (TV) natural orifice transluminal endoscopic surgery (NOTES) to date. TV NOTES is currently observed with critical eyes from the surgical community, despite encouraging data to suggest improved short-term recovery and pain. All TV NOTES procedures performed in female patients between 18 and 65 years of age were included. The median follow-up was 90 days. The TV appendectomies and ventral hernia repairs were pure NOTES, through a SILS port in the vagina, whereas TV cholecystectomies were hybrid procedures with the addition of a 5-mm port in the umbilicus. A total of 102 TV NOTES procedures, including 72 TV cholecystectomies, 24 TV appendectomies, and 6 TV ventral hernia repairs, were performed. The average age was 37 years old and body mass index was 29 kg/m. Three major and 7 minor complications occurred. The first major complication was a rectal injury during a TV access port insertion. The second major complication was an omental vessel bleed after a TV cholecystectomy. The third complication was an intra-abdominal abscess after a TV appendectomy. Seven minor complications were urinary retention (4), transient brachial plexus injury, dislodgement of an intrauterine device, and vaginal granulation tissue. As techniques in TV surgery are adopted, inevitably, complications may occur due to the inherent learning curve. Laparoscopic instruments, although adaptable to TV approaches, have yet to be optimized. A high index of suspicion is necessary to identify complications and optimize outcomes for patients.

  11. Natural orifice translumenal endoscopic surgery: Progress in humans since white paper

    Byron F Santos; Eric S Hungness

    2011-01-01

    Since the first description of the concept of natural orifice translumenal endoscopic surgery (NOTES), a substantial number of clinical NOTES reports have appeared in the literature. This editorial reviews the available human data addressing research questions originally proposed by the white paper, including determining the optimal method of access for NOTES, developing safe methods of lumenal closure, suturing and anastomotic devices,advanced multitasking platforms, addressing the risk of infection, managing complications, addressing challengeswith visualization, and training for NOTES procedures.An analysis of the literature reveals that so far transvaginal access and closure appear to be the most feasible techniques for NOTES, with a limited, but growing transgastric, transrectal, and transesophageal NOTES experience in humans. The theoretically increased risk of infection as a result of NOTES procedures has not been substantiated in transvaginal and transgastric procedures so far. Development of suturing and anastomotic devices and advanced platforms for NOTES has progressed slowly,with limited clinical data on their use so far. Data on the optimal management and incidence of intraoperative complications remain sparse, although possible factorscontributing to complications are discussed. Finally, this editorial discusses the likely direction of future NOTES development and its possible role in clinical practice.

  12. Does bladder outlet obstruction affect distance between the ureteric orifices in patients with benign prostate hyperplasia?

    Cüneyt Özden

    2009-01-01

    Full Text Available Objectives: Many morphological changes occur in the bladder due to bladder outlet obstruction (BOO in pa-tients with benign prostate hyperplasia (BPH. In the present study we evaluated the relationship between in-terureteric distance (IUD of the orifices and BOO in BPH patients.Materials and methods: Thirty-seven consecutive pa-tients with lower urinary tract symptoms at the urology polyclinic included in the study. Patients divided into 2 groups according to maximal flow rate (Qmax. The first group constituted of 18 patients with Qmax 15ml/s. The IUD measurement was performed with Doppler ultrasonography.Results: There was no significant difference between the groups regarding mean age and prostate volume. Mean IUD in the first group was 32.7±5.4 mm and mean IUD in the second group was 31.5±5.1 mm. There was no statistically significant difference between the groups regarding the IUD.Conclusions: Data obtained from the study revealed that measurement of IUD with Doppler ultrasonography not significantly related to BOO.

  13. Experimental study of mixed convection flow through a horizontal orifice or vent linking two compartments

    Varrall, Kevin

    2016-01-01

    To answer building issues and fire safety challenges, this thesis deals with the mixed convection flow through a horizontal orifice or vent linking two compartments. The aim is to improve the understanding and the modeling of the exchange of gas through the opening. A small scale experimental study and a theoretical approach are proposed. The study focuses first on the influence of the geometrical ratio L/D of the opening on the flow rate at the vent for free convection regime. Non-intrusive measurements, via the tracking of the interface between two non miscible liquids in an isothermal approach, and thanks to the SPIV in a thermal approach, permit to describe the bidirectional exchange process and to consolidate existing correlations. Experiments for mixed convection regime aim to study the impact of mechanical ventilation (in blowing and extracting modes) on the exchanged flow rates. The comparison between existing correlations and experimental data shows large differences. A modification of the correlation of Cooper is proposed. A theoretical approach from the simplified Navier Stokes equations and with the Boussinesq approximation permits to discuss the construction of existing correlations. From this theory, a more accurate model than those available in the literature is proposed thanks to an adjustment of discharge coefficients from experimental data. (author)

  14. Parametric study for welding residual stresses in nozzle of nuclear power plants using finite element method

    Kim, Wan Jae; Lee, Kyoung Soo; Kim, Tae Ryong [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Song, Tae Kwang [Korea Univ., Seoul (Korea, Republic of)

    2008-07-01

    Distribution of welding residual stresses are mainly characterized by degrees and frequencies of thermal loads applied to materials. However, other effects as component size and clamping condition can also affect stress distributions to a certain extent thus careful manipulation of these parameters based on clear understanding of how they affect residual stresses distributions and why can be additional measure to mitigate residual stresses. This paper discusses aforementioned issues for the case of safety and relief nozzle in nuclear power plant through finite element analysis.

  15. Critical flashing flows in nozzles with subcooled inlet conditions

    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

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

    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.

  17. Shock unsteadiness in a thrust optimized parabolic nozzle

    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.

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

    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.

  19. The role of nozzle convergence in diesel combustion

    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.

  20. An Intestinal Occlusion Device for Prevention of Small Bowel Distention During Transgastric Natural Orifice Transluminal Endoscopic Surgery

    Tomasko, Jonathan M.; Mathew, Abraham; Moyer, Matthew T.; Haluck, Randy S.; Pauli, Eric M.

    2013-01-01

    Background and Objectives: Bowel distention from luminal gas insufflation reduces the peritoneal operative domain during natural orifice transluminal endoscopic surgery (NOTES) procedures, increases the risk for iatrogenic injury, and leads to postoperative patient discomfort. Methods: A prototype duodenal occlusion device was placed in the duodenum before NOTES in 28 female pigs. The occlusion balloon was inflated and left in place during the procedure, and small bowel distension was subject...

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

    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.)

  2. Plasma acceleration by magnetic nozzles and shock waves

    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)

  3. Nuclear reactor fuel assembly with a removably top nozzle

    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

  4. Top-nozzle mounted replacement guide pin assemblies

    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)

  5. Evaluation of the flow-accelerated corrosion downstream of an orifice. 2. Measurement of corrosion rate and evaluation on the effects of the flow field

    Nagaya, Yukinori; Utanohara, Yoichi; Nakamura, Akira; Murase, Michio

    2008-01-01

    In this study, in order to evaluate the effects of flow field on corrosion rate due to flow accelerated corrosion (FAC), a corrosion rate downstream of an orifice was measured using the electric resistance method. The diameter of the pipe is 50 mm and that of the orifice is 24.3 mm, and flow velocity of the experimental loop was set at 5m/s, and the temperature of water was controlled within ±1 at 150deg-C. There were no significant circumferential difference in measured corrosion rate, and the maximum corrosion rate was observed at 1D or 2D downstream from the orifice. The ratios of the measured corrosion rate and the calculated wall shear stress at the 1D downstream from the orifice to the value at upstream under well developed flow agreed well. (author)

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

    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.

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

    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

    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

    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

    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. Asian-Chinese patient perceptions of natural orifice transluminal endoscopic surgery cholecystectomy.

    Teoh, Anthony Yuen Bun; Ng, Enders Kwok Wai; Chock, Alana; Swanstrom, Lee; Varadarajulu, Shyam; Chiu, Philip Wai Yan

    2014-05-01

    Patient and physician perceptions of natural orifice transluminal endoscopic surgery (NOTES) have been reported for the Western population. However, whether Asian-Chinese patients share the same perspectives as compared to the Western population is unknown. This was a cross-sectional survey carried out in the surgical outpatient's clinic at the Prince of Wales Hospital between June and September 2011. Patients were provided with an information leaflet and asked to complete a questionnaire regarding their perceptions of and preferences for NOTES cholecystectomy. Female patients attending the clinic were given an additional questionnaire regarding attitudes towards transvaginal surgery. Two hundred patients were recruited to complete the questionnaire(s) and the male to female ratio was 1:1. One hundred and fourteen patients (57%) preferred to undergo NOTES cholecystectomy for cosmetic reasons (P=0.009). Oral and anal routes were both acceptable for NOTES accesses in males and females. Forty-one percent of the female patients would consider transvaginal NOTES. Of these patients, significantly more patients indicated that the reason for choosing transvaginal NOTES was to minimize the risk of hernia (P=0.016) and to reduce pain associated with the procedure (P=0.017). The risk of complications (84.5%) and the cost of the procedure (58%) were considered the most important aspects when choosing a surgical approach by Asian-Chinese patients. Asian-Chinese preferred NOTES mainly for cosmetic reasons. However, the transvaginal route was less acceptable to females. Significant differences in patient perception on NOTES were observed between Asian-Chinese and Western patients. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

  12. Oophorectomy by natural orifice transluminal endoscopic surgery: feasibility study in dogs.

    Freeman, Lynetta J; Rahmani, Emad Y; Sherman, Stuart; Chiorean, Michael V; Selzer, Don J; Constable, Peter D; Snyder, Paul W

    2009-06-01

    Natural orifice transluminal endoscopic surgery (NOTES) represents a potentially less-invasive alternative to conventional or laparoscopic surgery. Our purpose was to develop a canine oophorectomy model for prospective evaluation of intraoperative complications, surgical stress, and postoperative pain and recovery with NOTES. Feasibility study. Academic preclinical research. Ten healthy female dogs. NOTES procedures were performed through gastric access with an electrocautery snare to resect and retrieve the ovaries. The gastrotomy was closed with prototype T-fasteners. Operative time; complications; postoperative pain scores, and nociceptive threshold; surgical stress markers (interleukin-6 [IL-6], C-reactive protein); systemic stress parameters (cortisol, glucose); necropsy evaluation at 10 to 14 days. The mean operative time was 154 minutes (SD +/- 58 minutes) and no animals died as a result of complications from the procedure. The primary difficulty was incomplete ovarian excision and conversion to an open procedure in 1 dog. Serum glucose concentrations increased after surgery and remained elevated for at least 36 hours. The serum cortisol concentration was transiently increased from baseline at 2 hours after surgery. The serum IL-6 concentration peaked at 2 hours after surgery and returned to the baseline value by 18 hours. The serum C-reactive protein concentration increased significantly from baseline, peaked at 12 hours after surgery, and then slowly declined toward baseline but remained elevated at 72 hours after surgery. Nociceptive threshold measurements indicated increased sensitivity to pain for 2 to 24 hours after surgery. At necropsy, surgical sites were healing uneventfully with no significant damage to surrounding organs, no significant growth on bacterial cultures, and no evidence of peritonitis. Small number of animals, single center. The NOTES approach to oophorectomy in dogs appears to be a reasonable alternative to traditional surgery

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

    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.

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

    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.

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

    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.

  16. Experimental assessment of heat and mass transfer of modular nozzles of cooling towers

    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.

  17. Computational Simulation on a Coaxial Substream Powder Feeding Laval Nozzle of Cold Spraying

    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

  18. High Velocity Jet Noise Source Location and Reduction. Task 6. Noise Abatement Nozzle Design Guide.

    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

  19. Analysis and design of optimized truncated scarfed nozzles subject to external flow effects

    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.

  20. Fungicides efficiency on wheat diseases control in response to the application with different spray nozzles

    Felipe Rafael Garcés Fiallos

    2011-12-01

    Full Text Available This study aimed to evaluate the efficiency of fungicides to leaf control diseases of wheat, when applied to different models of spray nozzles. The experiment was conducted in a randomized block design with four replicates of factorial (4 x 3+1. Data were subjected to analysis of variance and means compared by Tukey test at 5% probability. The fungicides used were: Opera® (pyraclostrobin+epoxiconazole 0.75 L.ha-1 , Opera® 0.75 L.ha-1 +Folicur® (tebuconazole 0.3 L.ha-1 , Priori Xtra® (azoxystrobin+cyproconazole 0.3 L.ha-1 , Priori Xtra® 0.3 L.ha-1 +Tilt® (propiconazole 0.3 L.ha-1 . These fungicides were applied with three models of spray nozzles jet planes: XR 11 001 (fine drop, AIRMIX 11,001 (average drop and AVI 11,001 (coarse drop. We evaluated the incidence and severity (damage per plant leaf of yellow spot (Drechslera tritici-repentis, spot blotch (Bipolaris sorokiniana, leaf rust (Puccinia triticina and grain yield (kg.ha-1 culture. The results show that the application of fungicides for control of leaf diseases in wheat resulted in increases in grain yield, and yield higher values were observed with the application of Opera®, using the XR 11001.

  1. Efeito de pontas de pulverização no controle químico da ferrugem da soja Spray nozzle effect on soybean rust chemical control

    João P. A. R. da Cunha

    2008-06-01

    Full Text Available O controle químico eficiente da ferrugem asiática da soja depende da correta seleção da ponta de pulverização. Este trabalho teve o objetivo de avaliar o efeito da utilização de diferentes pontas de pulverização na aplicação de fungicida para o controle da ferrugem da soja. O ensaio foi conduzido no delineamento em blocos ao acaso, com quatro repetições, em esquema fatorial (4 x 2 + 1: quatro tipos de ponta de pulverização (jato plano defletor duplo, jato plano duplo com pré-orifício e jato cônico vazio com e sem indução de ar, dois volumes de aplicação (150 e 200 L ha-1 e um tratamento adicional que não recebeu fungicida. Realizou-se a semeadura direta da cultivar de soja M-SOY 8008 (ciclo precoce, avaliando-se, após a aplicação do fungicida tebuconazole, a deposição de calda no dossel da cultura, a severidade da ferrugem, o grau de desfolha e a produtividade. Concluiu-se que não houve influência dos tipos de pontas de pulverização e dos volumes de calda no controle da ferrugem. Na parte inferior do dossel, a cobertura proporcionada com a utilização das quatro pontas foi inferior a 7% da área, sendo, portanto, necessário buscar estratégias que incrementem essa deposição. O fungicida reduziu a severidade da ferrugem da soja, o que refletiu na produtividade, que foi, em média, 157% superior à obtida na testemunha.Soybean rust chemical control depends on the correct selection of the spray nozzles. This study evaluated the spray nozzle effect on soybean rust control application. A randomized complete-block design with four replications was used, in a factorial model (4 x 2 + 1: four spray nozzles (hollow cone spray nozzles, with and without air induction, pre-orifice twin flat fan and turbo twin flat fan, two spray volumes (150 and 200 L ha-1 and the control (non-treated plot. M-SOY 8008 soybean (early cycle was sown. After the application of the fungicide tebuconazole, with the different nozzles and volume

  2. Comparison of finite element and influence function methods for three-dimensional elastic analysis of boiling water reactor feedwater nozzle cracks. Phase report

    Besuner, P.M.; Caughey, W.R.

    1976-11-01

    The finite element (FE) and influence function (IF) methods are compared for a three-dimensional elastic analysis of postulated circular-shaped surface cracks in the feedwater nozzle of a typical boiling water reactor (BWR). These are two of the possible methods for determining stress intensity factors for nozzle corner cracks. The FE method is incorporated in a direct manner. The IF method is used to compute stress intensity factors only when the uncracked stress field (i.e., the stress in the uncracked solid at the locus of the crack to be eventually considered) has been computed previously. Both the IF and FE methods are described in detail and are applied to several test cases chosen for their similarity to the nozzle crack problem and for the availablility of an accurate published result obtained from some recognized third method of solution

  3. Effects of dimensional size and surface roughness on service performance for a micro Laval nozzle

    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)

  4. Nuclear reactor fuel assembly with a removable top nozzle

    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

  5. Calibration of nozzle for air mass flow measurement

    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.

  6. 46 CFR 181.320 - Fire hoses and nozzles.

    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...

  7. The separation nozzle process for uranium isotope enrichment

    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

  8. Separation of finest dusts in Venturi scrubber with hybrid nozzles

    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.)

  9. The jet nozzle process for uranium 235 isotopic enrichment

    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

  10. Design and Analysis of Elliptical Nozzle in AJM Process using ...

    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.

  11. Ayame/PAM-D apogee kick motor nozzle failure analysis

    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,

  12. High-Melt Carbon-Carbon Coating for Nozzle Extensions

    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.

  13. Computation of stress intensity factors for nozzle corner cracks by various finite element procedures

    Broekhoven, M.J.G.

    1975-01-01

    The present study aims at deriving accurate K-factors for a series of 5 elliptical nozzle corner cracks of increasing size by various finite element procedures, using a three-level recursive substructuring scheme to perform the computations in an economic way on an intermediate size computer (IBM 360/65 system). A nozzle on a flat plate has been selected for subsequent experimental verification, this configuration being considered an adequate simulation of a nozzle on a shallow shell. The computations have been performed with the ASKA finite element system using mainly HEXEC-27 (incomplete quartic) elements. The geometry has been subdivided into 5 subnets with a total of 3515 nodal points and 6250 unknowns, two main nets and one hyper net. Each crack front is described by 11 nodal points and all crack front nodes are inserted in the hyper net, which allows for the realization of the successive crack geometries by changing only a relatively small hyper net (615 to 725 unknowns). Output data have been interpreted in terms of K-factors by the global energy method, the displacement method and the stress method. Besides, a stiffness derivative procedure, recently developed at Brown University, which takes full advantage of the finite element formulation to calculate local K-factors, has been applied. Finally it has been investigated whether sufficiently accurate results can be obtained by analyzing a considerably smaller part than one half of the geometry (as strictly required by symmetry considerations), using fixed boundary conditions derived from a far cheaper analysis of the uncracked structure

  14. Decolorization of Acid Orange 7 by an electric field-assisted modified orifice plate hydrodynamic cavitation system: Optimization of operational parameters.

    Jung, Kyung-Won; Park, Dae-Seon; Hwang, Min-Jin; Ahn, Kyu-Hong

    2015-09-01

    In this study, the decolorization of Acid Orange 7 (AO-7) with intensified performance was obtained using hydrodynamic cavitation (HC) combined with an electric field (graphite electrodes). As a preliminary step, various HC systems were compared in terms of decolorization, and, among them, the electric field-assisted modified orifice plate HC (EFM-HC) system exhibited perfect decolorization performance within 40 min of reaction time. Interestingly, when H2O2 was injected into the EFM-HC system as an additional oxidant, the reactor performance gradually decreased as the dosing ratio increased; thus, the remaining experiments were performed without H2O2. Subsequently, an optimization process was conducted using response surface methodology with a Box-Behnken design. The inlet pressure, initial pH, applied voltage, and reaction time were chosen as operational key factors, while decolorization was selected as the response variable. The overall performance revealed that the selected parameters were either slightly interdependent, or had significant interactive effects on the decolorization. In the verification test, complete decolorization was observed under statistically optimized conditions. This study suggests that EFM-HC is a useful method for pretreatment of dye wastewater with positive economic and commercial benefits. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Heat exchanger nozzle stresses due to pipe vibration

    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

  16. Vortex flow and cavitation in diesel injector nozzles

    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

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

    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.

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

    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.

  19. Long-term survival in children with atrioventricular septal defect and common atrioventricular valvar orifice in Sweden.

    Frid, Christina; Björkhem, Gudrun; Jonzon, Anders; Sunnegårdh, Jan; Annerén, Göran; Lundell, Bo

    2004-02-01

    The survival for patients with atrioventricular septal defect has improved markedly over the last decades and, during the same period, the survival of children with Down's syndrome has also increased. The aim of our study was to investigate long-term survival in patients having atrioventricular septal defect with common valvar orifice, but without associated significant congenital heart defects, in the setting of Down's syndrome, comparing the findings to those in chromosomally normal children with the same malformation. In a population-based retrospective study, we scrutinised the medical records from 801 liveborn children with atrioventricular septal defect born in Sweden during the period 1973 through 1997. Data on gender, presence or absence of Down's syndrome, associated congenital heart defects, date of birth, operation and death were recorded and followed up until 2001. An isolated atrioventricular septal defect with common atrioventricular valvar orifice was present in 502 children, of whom 86% had Down's syndrome. We found a significant reduc tion over time in age at operation, and in postoperative mortality at 30 days, from 28 to 1%. Using a multiple logistic regression model, we found no significant differences in mortality between genders, nor between those with or without Down's syndrome. Early corrective surgery could not be identified as a significant independent factor for survival. The 5-year postoperative survival in patients with Down's syndrome increased from 65% over the period from 1973 through 1977, to about 90% in the period 1993 through 1997, and the same trend was observed in chromosomally normal patients. Survival in uncomplicated atrioventricular septal defect with common atrioventricular valvar orifice has greatly increased, and surgical correction is now equally successful in patients with Down's syndrome and chromosomally normal patients, and for both genders. Death in connection with surgery is no longer the major threat, and focus

  20. Turbine combustor with fuel nozzles having inner and outer fuel circuits

    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

    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

    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. Pressure drop calculation using a one-dimensional mathematical model for two-phase flow through an orifice

    Petkov, K.P.; Puton, M; Madsen, Søren Peder

    2014-01-01

    are accounted for through both friction and acceleration as in a conventional formulation. However, in this analysis the acceleration term is both attributed geometrical effects through the area change and fluid dynamic effects through the expansion of the two-phase flow. The comparison of numerical...... is a one dimensional formulation in space and the equations incorporates the change in tubes and orifice diameter as formulated in (S. Madsen et.al., Dynamic Modeling of Phase Crossings in Two-Phase Flow, Communications in Computational Physics 12 (4), 1129-1147). The pressure changes in the flow...

  4. Construction and evaluation of a hollow cone type nozzle with ceramic nanocomposites

    F Amirshaghaghi

    2015-09-01

    products. In order to prepare nanocomposite powder mixed with stabilized zirconia alumina, the ratio of 10/90 percent by volume of the powder was poured into the mill for three hours and it was stirred in the mixer. Pressing is placing the powder into a mold, and applying pressure to achieve the desired density. In this study, pressing device with 30 tons was manually used and powder sample in the amount of one gram was placed in a semi-cylindrical small hollow. After making a few samples and determining the optimal pressure and time of pressing in action, samples were manufactured under 90 kg cm-2 pressure at 20 seconds. A high temperature furnace model F3L-1720 was used for zintering. Samples were put into the furnace after forming by a single-axis press. Temperature the of furnace was raised up 1650°C at a rate of 10 degrees per minute and then the samples were exposed for one hour in order for the heat to be evenly applied in all the body of the nozzle. Finally, a hollow cone spray pattern fan nozzle with a major diameter of 15 mm and an inner diameter of 2 mm was built. Equipment for analyzing used in this study included: X-Ray Diffraction device (XRD, Scanning Electron Microscope (SEM. The flow rate output was measured at a pressure of 2 bar in the period of 0-50 hours at 1, 2, 3, 4, 5, 8, 10, 15, 20, 25, 30, 40 and 50 hours. Results and Discussion: XRD analysis of nano-composite stabilizer in the presence of yttria- zirconia- alumina toughness with (Al2O3-ZrO2-Y2O3, yttria stabilized zirconia (ZrO2-Y2O3 and alumina indicates respective phases. For the samples made with better properties, it should be uniformly distributed within it. To evaluate the uniformity, SEM-Mapping test samples were made. The results showed that the distribution of Y, Zr, Al in nanocomposite (Al2O3-ZrO2-Y2O3 is almost uniform. The results of changes in the level of output over time showed that the rate of flow in composite (Al2O3-ZrO2-Y2O3 nozzle versus ceramic conventional (Al2O3 nozzle

  5. The proton therapy nozzles at Samsung Medical Center: A Monte Carlo simulation study using TOPAS

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

    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).

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

    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

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

    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).

  9. A static investigation of yaw vectoring concepts on two-dimensional convergent-divergent nozzles

    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.

  10. Failure analysis of the Ringhals unit 3 EDM surfaces removed from the RPV outlet nozzle to safe end weld

    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

  11. Structural evaluation of IEA-R1 primary system pump nozzles

    Fainer, Gerson; Faloppa, Altair A.; Oliveira, Carlos A. de; Mattar Neto, Miguel, E-mail: gfainer@ipen.br, E-mail: afaloppa@ipen.br, E-mail: calberto@ipen.br, E-mail: mmattar@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    The IEA-R1 pumps of the primary coolant system may be required to withstand design and operational conditions. IEA-R1 nuclear research reactor is an open pool type reactor operated by IPEN since 1957. The reactor can be operated up to 5MW heating power since it was upgraded in a modernization program conducted by IPEN. The primary coolant system is composed by the piping system, decay tank, two heat pumps and two heat exchangers. In the latest arrangement upgrade of the primary system, conducted in 2014 as part of an aging management program, a partial replacement of the coolant piping and total replacement of piping and pump supports were done. As consequence, reviewed loads in the pump nozzles were obtained demanding a new evaluation of them. The aim of this report is to present the structural evaluation of the pump nozzles, considering the new loads coming from the new piping layout, according to: API 610 code verification, Supplier loads and structural analysis applying finite element method, by using the ANSYS computer program, regarding ASME VIII Div 1 & 2 recommendations. (author)

  12. Design of Single Stage Axial Turbine with Constant Nozzle Angle Blading for Small Turbojet

    Putra Adnan, F.; Hartono, Firman

    2018-04-01

    In this paper, an aerodynamic design of a single stage gas generator axial turbine for small turbojet engine is explained. As per design requirement, the turbine should be able to deliver power output of 155 kW at 0.8139 kg/s gas mass flow, inlet total temperature of 1200 K and inlet total pressure of 335330 Pa. The design phase consist of several steps, i.e.: determination of velocity triangles in 2D plane, 2D blading design and 3D flow analysis at design point using Computational Fluid Dynamics method. In the determination of velocity triangles, two conditions are applied: zero inlet swirl (i.e. the gas flow enter the turbine at axial direction) and constant nozzle angle design (i.e. the inlet and outlet angle of the nozzle blade are constant from root to tip). The 2D approach in cascade plane is used to specify airfoil type at root, mean and tip of the blade based on inlet and outlet flow conditions. The 3D approach is done by simulating the turbine in full configuration to evaluate the overall performance of the turbine. The observed parameters including axial gap, stagger angle, and tip clearance affect its output power. Based on analysis results, axial gap and stagger angle are positively correlated with output power up to a certain point at which the power decreases. Tip clearance, however, gives inversely correlation with output power.

  13. A comprehensive study on the effect of cavitation on injection velocity in diesel nozzles

    Javier López, J.; Salvador, F.J.; Garza, Oscar A. de la; Arrègle, Jean

    2012-01-01

    Highlights: ► Cavitation has an indirect effect on the effective injection velocity. ► Cavitation in the injector hole reduces locally the fluid viscosity. ► A lower viscosity leads to a more turbulent velocity profile. ► The more turbulent velocity profile justifies the increase in effective velocity. - Abstract: Results when testing cavitating injection nozzles show a strong reduction in mass flow rate when cavitation appears (the flow is choked), while the momentum flux is reduced to a lesser extent, resulting in an increase in effective injection velocity. So as to better understand the origin of this increase in effective injection velocity, the basic equations for mass and momentum conservation were applied to an injection nozzle in simplified conditions. The study demonstrated that the increase in injection velocity provoked by cavitation is not a direct effect of the latter, but an indirect effect. In fact, the vapor appearance inside the injection hole produces a decrease in the viscosity of the fluid near the wall. This leads to lower momentum flux losses and to a change in the velocity profile, transforming it into a more “top hat” profile type. This change in the profile shape allows explaining why the momentum flux reduction is not so important compared to that of the mass flow rate, thus explaining why the effective injection velocity increases.

  14. Structural evaluation of IEA-R1 primary system pump nozzles

    Fainer, Gerson; Faloppa, Altair A.; Oliveira, Carlos A. de; Mattar Neto, Miguel

    2017-01-01

    The IEA-R1 pumps of the primary coolant system may be required to withstand design and operational conditions. IEA-R1 nuclear research reactor is an open pool type reactor operated by IPEN since 1957. The reactor can be operated up to 5MW heating power since it was upgraded in a modernization program conducted by IPEN. The primary coolant system is composed by the piping system, decay tank, two heat pumps and two heat exchangers. In the latest arrangement upgrade of the primary system, conducted in 2014 as part of an aging management program, a partial replacement of the coolant piping and total replacement of piping and pump supports were done. As consequence, reviewed loads in the pump nozzles were obtained demanding a new evaluation of them. The aim of this report is to present the structural evaluation of the pump nozzles, considering the new loads coming from the new piping layout, according to: API 610 code verification, Supplier loads and structural analysis applying finite element method, by using the ANSYS computer program, regarding ASME VIII Div 1 & 2 recommendations. (author)

  15. Numerical investigation on transient flow and cavitation characteristic within nozzle during the oil drainage process for a high-pressure common-rail DI diesel engine

    Sun, Zuo-Yu; Li, Guo-Xiu; Yu, Yu-Song; Gao, Si-Chao; Gao, Guo-Xi

    2015-01-01

    Highlights: • The flow process within nozzle during oil drainage process were studied. • The effects of needle movement on flow characteristics were studied. • The cavitation characteristics in a transient flow were numerical studied. - Abstract: In the present investigation, the transient developments of flow and cavitation within an injector’s nozzle during the oil drainage process have been studied by numerical method for a high-pressure common-rail DI diesel engine, both the variation regulations of macro parameters (indicating flow characteristics and cavitation characteristics) and the distribution manners of important physical fields (indicating the cavitation evolution in the micro) have been obtained and analyzed. The obtained numerical results indicate that, during the oil drainage process, both mass flow rate and flow coefficient monotonously increase with declining variation rates, both averaged flow velocity and averaged turbulent kinetic energy also monotonously increase; however, to the curve of TKE-needle lift, there exist certain points give abrupt increase. The difference in TKE curve compared to averaged flow velocity is mainly attributed to the sudden variation of cavitation. Based upon the numerical results, the cavitation bubble will not be formed until the needle lift has been raised to a certain position due to the lower flow velocity and the lack of low (even negative) pressure zones. As needle rises, the primary bubbles are formed near the lower corner after nozzle’s entrance; but as needle further rises, the positions at where bubbles are formed have been transferred to the upper corner and then being blow downwards orifice as the increase of flow velocity

  16. SINGLE PHASE ANALYTICAL MODELS FOR TERRY TURBINE NOZZLE

    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

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

    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

  18. Cirugía endoscópica transluminal por orificios naturales: NOTES Natural orifice transluminal endoscopic surgery: NOTES

    M. J. Varas Lorenzo

    2009-04-01

    Full Text Available Se presenta una revisión actual, puesta al día, y punto de vista de los autores sobre un tema sumamente novedoso y atractivo, como es la Cirugía Endoscópica Transluminal por Orificios Naturales (NOTES: Natural Orifice Translumenal Endoscopic Surgery. La mayoría de los trabajos revisados se han realizado en animales de experimentación, pero la publicación de la colecistectomía por vía transvaginal, y la aparición de editoriales y artículos de revisión sobre el tema, nos llevan a realizar una serie de preguntas no resueltas actualmente sobre este tipo de cirugía, que representa un avance potencial para conseguir "una cirugía endoscópica sin cicatrices, sin infecciones, con mínimos requerimientos de anestesia y una inmediata recuperación".A current review and update of an exceedingly novel and appealing topic, namely natural orifice transluminal endoscopic surgery (NOTES, is discussed, as well as the authors' viewpoint thereon. Most reviewed studies were performed in laboratory animals, but reports on transvaginal cholecystectomy and the emergence of editorials and review articles on this topic pose a number of as yet unanswered questions on this type of surgery, which represents a potential advance towards "endoscopic surgery with no scars, no infection, minimal anesthesia requirements, and immediate recovery".

  19. Experimental otitis media with effusion induced by electron beam irradiation to pharyngeal orifice of auditory tube in guinea pig

    Kokubu, Michiyo; Amatsu, Mutsuo

    1984-01-01

    The purpose of the present study was to obtain a more natural tubal insufficiency than that obtained by the conventional methods to clarify the middle ear pathology associated with tubal dysfunction. For this purpose, the pharyngeal orifice of the auditory tube in the guinea pigs was irradiated with electron beam with a dose of 2,000 rad following the preliminary experiments to determine the appropriate dose. The guinea pigs with intact drum and normal Pryer reflex were used for the present experiment series. A specially devised apparatus was used for avoiding the dipersing beam. Histopathological changes of the middle ear and auditory tube were observed in a series of single specimen with H-E staining 1, 2, 3, 6, 12 months after irradiation. In this study, middle ear with effusion was used to clarify the dynamic process of the pathological changes between the auditory tube and the middle ear. In summary, the present study revealed that the electron beam irradiation to the pharyngeal orifice caused various grades of otitis media with effusion which could be classified into three groups. Of these groups 1) and 2), 3) were likely to be corresponding with so-called serous and purulent otitis media with effusion in human respectively. Infection due to the malfunction caused by the epithelial damage of the auditory tube was an important promoting factor to change the serous type effusion for the purulent type effusion. (J.P.N.)

  20. Endoscopic management of intraoperative small bowel laceration during natural orifice translumenal endoscopic surgery: a blinded porcine study.

    Fyock, Christopher J; Forsmark, Chris E; Wagh, Mihir S

    2011-01-01

    Natural orifice translumenal endoscopic surgery (NOTES) has recently gained great enthusiasm, but there is concern regarding the ability to endoscopically manage complications purely via natural orifices. To assess the feasibility of endoscopically managing enteral perforation during NOTES using currently available endoscopic accessories. Twelve pigs underwent transgastric or transcolonic endoscopic exploration. Full-thickness enterotomies were intentionally created to mimic accidental small bowel lacerations during NOTES. These lacerations were then closed with endoclips. In the blinded arm of the study, small bowel repair was performed by a second blinded endoscopist. Adequate closure of the laceration was confirmed with a leak test. Primary access sites were closed with endoclips or T-anchors. At necropsy, the peritoneal cavity was inspected for abscesses, bleeding, or damage to surrounding structures. The enterotomy site was examined for adequacy of closure, adhesions, or evidence of infection. Fifteen small bowel lacerations were performed in 12 animals. Successful closure was achieved in all 10 cases in the nonblinded arm. Survival animals had an uncomplicated postoperative course and all enterotomy sites were well healed without evidence of necrosis, adhesions, abscess, or bleeding at necropsy. Leak test was negative in all animals. In the blinded arm, both small intestinal lacerations could not be identified by the blinded endoscopist. Necropsy revealed open small bowel lacerations. Small intestinal injuries are difficult to localize with currently available flexible endoscopes and accessories. Endoscopic clips, however, may be adequate for closure of small bowel lacerations if the site of injury is known.

  1. Two-Nozzle Flame Spray Pyrolysis (FSP) Synthesis of CoMo/Al2O3 Hydrotreating Catalysts

    Høj, Martin; Pham, David K.; Brorson, Michael

    2013-01-01

    and the hydrodenitrogenation activity improved from 70 to 90 % relative activity. This suggests that better promotion of the active molybdenum sulfide phase was achieved when using two-nozzle FSP synthesis, probably due to less formation of the undesired phase CoAl2O4, which makes Co unavailable for promotion.......Two-nozzle frame spray analysis (FSP) synthesis of CoMo/Al2O3 where Co and Al are sprayed in separate flames was applied to minimize the formation of CoAl2O4 observed in one-nozzle flame spray pyrolysis (FSP) synthesis and the materials were characterized by N2-adsorption (BET), X-ray diffraction...... (XRD), UV–vis diffuse reflectance spectroscopy, Raman spectroscopy, transmission electron microscopy, and catalytic performances in hydrotreating. By varying the flame mixing distances (81–175 mm) the amount of CoAl2O4 could be minimized. As evidenced by UV–vis spectroscopy, CoAl2O4 was detected only...

  2. Investigations into the operating behavior of separation nozzle cascades for uranium-235 enrichment in a 10-stage pilot plant

    Bley, P.; Hein, H.; Linder, G.

    1984-03-01

    The separation nozzle method developed by the Karlsruhe Nuclear Research Center is based on the centrifugal force in a curved jet consisting of uranium hexafluoride and a light auxiliary gas. To determine in experiments the operating and controlling behavior of separation nozzle cascades a 10-stage pilot plant was erected some year ago. This plant was transferred to the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) in Belo Horizonte as a donation made within the framework of the German-Brazilian Agreement on scientific cooperation in the field of uranium enrichment. The plant previously equipped with single deflection systems was modified to operate with the double deflection system envisaged for commercial plants. A controlling concept meanwhile developed and improved for separation nozzle cascades equipped with single and double deflection systems was verified experimentally and optimized at the pilot plant of the CDTN. A comparison of the experimental operating behavior with the operating behavior calculated by simulation programs has confirmed the faithfulness of simulation of the computer codes developed to apply to cascades with double deflection systems as well. (orig.) [de

  3. Apparatus and method for a gas turbine nozzle

    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.

  4. Three-Dimensional Flow Behavior Inside the Submerged Entry Nozzle

    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.

  5. Analysis of cracked pressure vessel nozzles by finite elements

    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.)

  6. Hypersonic nozzle/afterbody CFD code validation. I - Experimental measurements

    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.

  7. Bundled multi-tube nozzle for a turbomachine

    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.

  8. Investigation of nozzle contours in the CSIR supersonic wind tunnel

    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...

  9. Scalable Fabrication of Supercapacitors by Nozzle-free Electrospinning

    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 ...

  10. Effective hydraulic resistance of actuator nozzle generating a periodic jet

    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

  11. Ambipolar ion acceleration in an expanding magnetic nozzle

    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.

  12. Characterization of Rotating Detonation Engine Exhaust Through Nozzle Guide Vanes

    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

  13. Magnetic Nozzles for Plasma Thrusters: Acceleration, Thrust, and Detachment Mechanisms

    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

  14. Device to enrich uranium using the separation nozzle method

    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)

  15. Three Dimensional Steady Subsonic Euler Flows in Bounded Nozzles

    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...

  16. 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

    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

  17. CFD Models of a Serpentine Inlet, Fan, and Nozzle

    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

  18. Chemical processes in the turbine and exhaust nozzle

    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.

  19. Nozzle Flow with Vibrational Nonequilibrium. Ph.D. Thesis

    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.

  20. Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

    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

  1. Cracking at nozzle corners in the nuclear pressure vessel industry

    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

  2. Chemical processes in the turbine and exhaust nozzle

    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.

  3. Thermal Analysis of the Fastrac Chamber/Nozzle

    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.

  4. Thermal Analysis of the MC-1 Chamber/Nozzle

    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.

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

    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.

  6. Influence of throttling of the heavy fraction on the uranium isotope separation in the separation nozzle

    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

  7. Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

    Benhamadouche, S., E-mail: sofiane.benhamadouche@edf.fr; Arenas, M.; Malouf, W.J.

    2017-02-15

    Highlights: • Wall-resolved LES can predict the flow through a square-edged orifice at Re = 25,000. • LES results are compared with the available experimental data and ISO 5167-2. • Pressure loss and discharge coefficients are in very good agreement with ISO 5167-2. • The present wall-resolved LES could be used as reference data for RANS validation. - Abstract: The orifice plate is a pressure differential device frequently used for flow measurements in pipes across different industries. The present study demonstrates the accuracy obtainable using a wall-resolved Large Eddy Simulation (LES) approach to predict the velocity, the Reynolds stresses, the pressure loss and the discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number of 25,000. The ratio of the orifice diameter to the pipe diameter is β = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11. The mesh is sized using refinement criteria at the wall and preliminary RANS results to ensure that the solution is resolved beyond an estimated Taylor micro-scale. The inlet condition is simulated using a recycling method, and the LES is run with a dynamic Smagorinsky sub-grid scale (SGS) model. The sensitivity to the SGS model and to the pressure–velocity coupling is shown to be small in the present study. The LES is compared with the available experimental data and ISO 5167-2. In general, the LES shows good agreement with the velocity from the experimental data. The profiles of the Reynolds stresses are similar, but an offset is observed in the diagonal stresses. The pressure loss and discharge coefficients are shown to be in very good agreement with the predictions of ISO 5167-2. Therefore, the wall-resolved LES is shown to be highly accurate in simulating the flow across a square-edged orifice.

  8. Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

    Benhamadouche, S.; Arenas, M.; Malouf, W.J.

    2017-01-01

    Highlights: • Wall-resolved LES can predict the flow through a square-edged orifice at Re = 25,000. • LES results are compared with the available experimental data and ISO 5167-2. • Pressure loss and discharge coefficients are in very good agreement with ISO 5167-2. • The present wall-resolved LES could be used as reference data for RANS validation. - Abstract: The orifice plate is a pressure differential device frequently used for flow measurements in pipes across different industries. The present study demonstrates the accuracy obtainable using a wall-resolved Large Eddy Simulation (LES) approach to predict the velocity, the Reynolds stresses, the pressure loss and the discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number of 25,000. The ratio of the orifice diameter to the pipe diameter is β = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11. The mesh is sized using refinement criteria at the wall and preliminary RANS results to ensure that the solution is resolved beyond an estimated Taylor micro-scale. The inlet condition is simulated using a recycling method, and the LES is run with a dynamic Smagorinsky sub-grid scale (SGS) model. The sensitivity to the SGS model and to the pressure–velocity coupling is shown to be small in the present study. The LES is compared with the available experimental data and ISO 5167-2. In general, the LES shows good agreement with the velocity from the experimental data. The profiles of the Reynolds stresses are similar, but an offset is observed in the diagonal stresses. The pressure loss and discharge coefficients are shown to be in very good agreement with the predictions of ISO 5167-2. Therefore, the wall-resolved LES is shown to be highly accurate in simulating the flow across a square-edged orifice.

  9. Thermal stresses at nozzles of nuclear steel containments under LOCA-conditions

    Sanchez Sarmiento, G.; Bergmann, A.N.

    1986-01-01

    During a loss of coolant accident (LOCA) of a PWR-nuclear power plant, a considerable heating of the containment atmosphere is expected to occur. Transient thermal stresses will appear at the containment as a consequence of a non-uniform rise of its temperature. Applying computer codes based on the finite element method, dimensionless general thermal stresses at nozzles of spherical steel containment have been calculated, varying the principal geometrical parameters and the Biot number for the containment internal surface. Atmosphere temperature and Biot number are assumed constant after the accident. Several plots of the maximum principal stresses are provided, which constitute general results applicable to stress analysis of any particular containment of this kind. (orig.)

  10. Shape modification for decreasing the spring stiffness of double-plate nozzle type spacer grid spring

    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

    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. A CFD-based aerodynamic design procedure for hypersonic wind-tunnel nozzles

    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.

  13. Measurement of the residual stresses in a PWR Control Rod Drive Mechanism nozzle

    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...

  14. The Effect of Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions

    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

  15. INVESTIGATION OF FLOW BEHAVIOR IN MINIMUM QUANTITY LUBRICATION NOZZLE FOR END MILLING PROCESSES

    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...

  16. Simulation of Micro-Channel and Micro-Orifice Flow Using Lattice Boltzmann Method with Langmuir Slip Model

    A. R. Rahmati

    2016-12-01

    Full Text Available Because of its kinetic nature and computational advantages, the Lattice Boltzmann method (LBM has been well accepted as a useful tool to simulate micro-scale flows. The slip boundary model plays a crucial role in the accuracy of solutions for micro-channel flow simulations. The most used slip boundary condition is the Maxwell slip model. The results of Maxwell slip model are affected by the accommodation coefficient significantly, but there is not an explicitly relationship between properties at wall and accommodation coefficient. In the present wok, Langmuir slip model is used beside LBM to simulate micro-channel and micro-orifice flows. Slip velocity and nonlinear pressure drop profiles are presented as two major effects in such flows. The results are in good agreement with existing results in the literature.

  17. Current status of natural orifice trans-endoscopic surgery (NOTES and laparoendoscopic single site surgery (LESS in urologic surgery

    Rafael E. Sanchez-Salas

    2010-08-01

    Full Text Available Laparoendoscopic single site surgery (LESS and natural orifice transluminal endoscopic surgery (NOTES represent novel approaches in urological surgery. To perform a review of the literature in order describe the current status of LESS and NOTES in Urology. References for this manuscript were obtained by performing a review of the available literature in PubMed from 01-01-02 to 15-05-09. Search terms included single port, single site, NOTES, LESS and single incision. A total of 412 manuscripts were initially identified. Out of these, 64 manuscripts were selected based in their urological content. The manuscript features subheadings for experimental and clinical studies, as NOTES-LESS is a new surgical technique and its future evolution will probably rely in initial verified feasibility. A subheading for reviews presents information regarding common language and consensus for the techniques. The issue of complications published in clinical series and the future needs of NOTES-LESS, are also presented.

  18. Prediction of flow rates through an orifice at pressures corresponding to the transition between molecular and isentropic flow

    DeMuth, S.F.; Watson, J.S.

    1985-01-01

    A model of compressible flow through an orifice, in the region of transition from free molecular to isentropic expansion flow, has been developed and tested for accuracy. The transitional or slip regime is defined as the conditions where molecular interactions are too many for free molecular flow modeling, yet not great enough for isentropic expansion flow modeling. Due to a lack of literature establishing a well-accepted model for predicting transitional flow, it was felt such work would be beneficial. The model is nonlinear and cannot be satisfactorily linearized for a linear regression analysis. Consequently, a computer routine was developed which minimized the sum of the squares of the residual flow for the nonlinear model. The results indicate an average accuracy within 15% of the measured flow throughout the range of test conditions. Furthermore, the results of the regression analysis indicate that the transitional regime lies between Knudsen numbers of approximately 2 and 45. 4 refs., 3 figs., 1 tab

  19. Current status and future perspectives in laparoendoscopic single-site and natural orifice transluminal endoscopic urological surgery.

    Autorino, Riccardo; Stein, Robert J; Lima, Estevão; Damiano, Rocco; Khanna, Rakesh; Haber, Georges-Pascal; White, Michael A; Kaouk, Jihad H

    2010-05-01

    Objective of this study is to provide an evidence-based analysis of the current status and future perspectives of scarless urological surgery. A PubMed search has been performed for all relevant urological literature regarding natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS). In addition, experience with LESS and NOTES at our own institution has been considered. All clinical and investigative reports for LESS and NOTES procedures in the urological literature have been considered. A wide variety of clinical procedures in urology have been successfully completed by using LESS techniques. Thus far, experience with NOTES has largely been investigational, although early clinical reports are emerging. Further development of instrumentation and platforms is necessary for both techniques to become more widely adopted throughout the urological community.

  20. Office hysteroscopic treatment of a vanishing external uterine orifice in a postmenopausal woman with an obstetrical history of 44 abortions

    Maurizio Guida

    2015-11-01

    Full Text Available Cervical stenosis, defined as cervical scarring of variable degree, represents a significant anatomical impediment to hysteroscopic procedures. Acquired cervical stenoses are more common than congenital forms and they are mainly associated with aging, estrogen–progesteron drugs, cervical trauma or carcinoma. The overcoming of cervical stenosis at office hysteroscopy is challenging and it often fails requiring the scheduling of the patient for an in-patient treatment under general anesthesia. We report the office hysteroscopy treatment of a vanishing external uterine orifice in a postmenopausal woman with an ultrasonographic report of a heterogeneous and thick endometrium suggestive of endometrial pathology, focusing on the main surgical steps to perform an adequate management.

  1. High performance Solid Rocket Motor (SRM) submerged nozzle/combustion cavity flowfield assessment

    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.

  2. An Interactive Method of Characteristics Java Applet to Design and Analyze Supersonic Aircraft Nozzles

    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.

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

    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

  4. Direct Numerical Simulation of Hypersonic Turbulent Boundary Layer inside an Axisymmetric Nozzle

    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. Development of built-in debris-filter bottom nozzle for PWR fuel assemblies

    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)

  6. Stress analysis of the HFIR HB-2 and HB-3 beam tube nozzles

    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

  7. Interior flow and near-nozzle spray development in a marine-engine diesel fuel injector

    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.

  8. Proposed Flight Research of a Dual-Bell Rocket Nozzle Using the NASA F-15 Airplane

    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.

  9. INVESTIGATION OF FLOW BEHAVIOR IN MINIMUM QUANTITY LUBRICATION NOZZLE FOR END MILLING PROCESSES

    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.

  10. Numerical modelling of the jet nozzle enrichment process

    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

  11. Transient Side Load Analysis of Out-of-Round Film-Cooled Nozzle Extensions

    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.

  12. Set-up and calibration of an indoor nozzle-type rainfall simulator for soil erosion studies

    Lassu, T.; Seeger, M.

    2012-04-01

    Rainfall simulation is one of the most prevalent methods used in soil erosion studies on agricultural land. In-situ simulators have been used to relate soil surface characteristics and management to runoff generation, infiltration and erosion, eg. the influence of different cultivation systems, and to parameterise erosion models. Laboratory rainfall simulators have been used to determine the impact of the soil surface characteristics such as micro-topography, surface roughness, and soil chemistry on infiltration and erosion rates, and to elucidate the processes involved. The purpose of the following study is to demonstrate the set-up and the calibration of a large indoor, nozzle-type rainfall simulator (RS) for soil erosion, surface runoff and rill development studies. This RS is part of the Kraijenhoff van de Leur Laboratory for Water and Sediment Dynamics in Wageningen University. The rainfall simulator consists from a 6 m long and 2,5 m wide plot, with metal lateral frame and one open side. Infiltration can be collected in different segments. The plot can be inclined up to 15.5° slope. From 3,85 m height above the plot 2 Lechler nozzles 460.788 are sprinkling the water onto the surface with constant intensity. A Zehnder HMP 450 pump provides the constant water supply. An automatic pressure switch on the pump keeps the pressure constant during the experiments. The flow rate is controlled for each nozzle by independent valves. Additionally, solenoid valves are mounted at each nozzle to interrupt water flow. The flow is monitored for each nozzle with flow meters and can be recorded within the computer network. For calibration of the RS we measured the rainfall distribution with 60 gauges equally distributed over the plot during 15 minutes for each nozzle independently and for a combination of 2 identical nozzles. The rainfall energy was recorded on the same grid by measuring drop size distribution and fall velocity with a laser disdrometer. We applied 2 different

  13. BWR feedwater nozzle and control rod drive return line nozzle cracking: resolution of generic technical activity A-10. Technical report

    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

  14. UT inspection of nozzles by 3D raytracing

    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)

  15. Analysis of cracked pressure vessel nozzles by finite elements

    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)

  16. Sludge mobilization with submerged nozzles in horizontal cylindrical tanks

    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

  17. Acoustic Investigation of Jet Mixing Noise in Dual Stream Nozzles

    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.

  18. Experimental observations of a complex, supersonic nozzle concept

    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.

  19. Performance modelling of plasma microthruster nozzles in vacuum

    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.

  20. Hybrid two fuel system nozzle with a bypass connecting the two fuel systems

    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.