Instantaneous cross sectional flow velocity profiles from early mitral flow in 10 healthy men were constructed by time interpolation of the velocity data from each point in sequentially delayed two...Full Text Available
The two-phase flow program is directed at understanding the hydrodynamics of two-phase flows. The two-phase flow regime is characterized by a series of flow patterns that are designated as bubble, slug, churn, and annular flow. Churn flow has received very little scientific attention. This lack of attention cannot be justified because calculations predict that the churn flow pattern will exist over a substantial portion of the two-phase flow zone in producing geothermal wells. The University of Houston is experimentally investigating the dynamics of churn flow and is measuring the holdup over the full range of flow space for which churn flow exists. These experiments are being conducted in an air/water vertical two-phase flow loop. Brown ...
Measurement of local steam condensation rates of cocurrent stratified flow of steam and subcooled water was carried out at atmospheric pressure in a horizontal rectangular channel. The channel was constructed of stainless steel with pyrex glass windows, a...
The purpose of this document is to use existing documentation to review the effectiveness of subsurface flow and surface flowconstructed wetlands in treating wastewater and to demonstrate the viability of treating effluent from Savannah River Site outfalls H-02 and H-04 with a subsurface flowconstructed wetland to lower copper, lead and zinc concentrations to within National Pollutant Discharge Elimination System (NPDES) Permit limits. Constructed treatment wetlands are engineered systems that have been designed and constructed to use the natural functions of wetlands for wastewater treatment. Constructed wetlands have significantly lower total lifetime costs and often lower capital costs than conventional treatment systems. The two main types of constructed wetlands are surface ...
The Tevatron accelerator at Fermilab incorporates long two-phase helium passages. During magnet design, the generalized flow map of Baker was used to predict homogeneous flow. Longer than expected magnet time constants led to this investigation. The importance of predicting the flow regime has been amplified with the advent of non-horizontal accelerator designs. A test setup was constructed at Fermilab to investigate two-phase helium flow regimes for conditions practical in accelerator designs. The setup consisted of a standard Tevatron satellite refrigerator, subcooling dewar, heater, 35 m long transfer line, and a specialized end box. A knife blade on the midplane of the transfer line diverted the flow from the upper and lower halves of the pipe to separate vessels in the end box. The amount of liquid above and below the plane was measured at various total ...
The traffic flow information guidance can improve the operating efficiency of regional traffic. On the basis of the information guidance model and survey data, this paper takes advantage of the VISSIM software to simulate the traffic in a region within the Southwest Second Ring of Beijing constructed by six roads and six intersections and makes a comparative evaluation on the operation of the regional road traffic flow before and after the implementation of the traffic flow information guidance measures. The analysis of five different guided flow cases shows that if the guided left-turn traffic flows in southbound I.A increases from 10% to 30%, the travel time of the left-turn traffic flow in southbound I.A has a reduction from 18% to 42%, and its delay also reduces from 234 s to 164 s. In...
Improvements in electric submersible pumping systems have resulted in a demonstrated downhole running life of one year for low horsepower units operating in 180 C brine. The implementation of a prototype pressurized lubrication system to prevent brine intrusion and loss of lubricating oil from the motor and protector sections has been successfully tested. Second generation pressurized lubrication systems have been designed and fabricated and will be utilized in downhole production pumping tests during FY84. Pumping system lifetime is currently limited by available power cable designs that are degraded by high-temperature brine. A prototype metal-sheathed power cable has been designed and fabricated and is currently undergoing destructive and nondestructive laboratory testing. This cable design has the potential for eliminating brine intrusion into the power delivery system through the use of a hermatically sealed cable from the surface to the downhole motor. The two-phase ...
In a positive polarity induction adder each of the induction cavities is a cathode, which emits electrons at a unique potential. These broad spectrum electrons strongly affect Magnetically Insulated Transmission Line (MITL) behavior. Electron flow decreases the cavity-to-MITL coupling efficiency, and reduces the power transport efficiency along the system. Also, the operating impedance of the MITL is lowered, reducing the diode impedance required for good coupling and good total system power efficiency. It is therefore imperative to understand the details of MITL electron flow. In previous work, measurement of MITL electron flow for a twenty-stage linear induction adder (Hermes III), operated in positive polarity, was compared with simulations. There was qualitative agreement, but some differences were noted. For example, measured electron flow in the first cavities was greater than in the simulations. ...
An inner-city development with pile foundations as well as the proximity to the river Neckar with a groundwater flow offered ideal conditions for this new building in Mannheim in order to heat and cool geothermally. Already with the planning phase, detailed numerical flow computations were necessary in order to prove the functionality of the energy concept.
This work concerns the development of a methodology the objective of which is to characterize and diagnose two-phase flow regime transitions. The approach is based on the fundamental assumption that a transition flow is less stationary than a flow with an established regime. During the first time, the efforts focused on: (1) the design and construction of an experimental loop, allowing to reproduce the main horizontal two-phase flow patterns, in a stable and controlled way; (2) the design and construction of an electrical impedance probe, providing an imaged information of the spatial phase distribution in the pipe; and (3) the systematic study of the joint time-frequency and time-scale analysis methods, which permitted to define an adequate parameter quantifying the unstationarity degree. During the second time, in order to verify the fundamental assumption, a ...
This work concerns the development of a methodology the objective of which is to characterize and diagnose two-phase flow regime transitions. The approach is based on the fundamental assumption that a transition flow is less stationary than a flow with an established regime. During the first time, the efforts focused on: (1) the design and construction of an experimental loop, allowing to reproduce the main horizontal two-phase flow patterns, in a stable and controlled way; (2) the design and construction of an electrical impedance probe, providing an imaged information of the spatial phase distribution in the pipe; and (3) the systematic study of the joint time-frequency and time-scale analysis methods, which permitted to define an adequate parameter quantifying the unstationarity degree. During the second time, in order to verify the fundamental assumption, a ...
Mitsubishi is developing a new type of accumulator incorporating the technology of fluidics as one of the seeds for the improved safety of the newly constructed pressurized water reactor plants. This accumulator employs a vortex flow control device, called a vortex damper, as a fluidic device to simplify the safety systems. A fundamental experimental study with a one-fifth scale model and confirmation tests with a one-third scale model to develop the vortex damper have been carried out, and satisfactory results have been achieved. The results of the confirmation tests under the prototype pressure conditions agree well with the basic tests. The flow rate ratio can be 5 to 6. The pressure loss coefficient in the large flow rate period is 8. A cavitation factor is the main parameter of the flow rate coefficient.
For the construction of underground facilities comprising access tunnels, connecting tunnels, main tunnels and disposal tunnels, a large number of tunnels will be excavated in deep rock formations. These excavations will extend hundreds kilometers in total length. Therefore, special attention must be paid, to transporting large volume of debris, ventilation, emergency escape routes in case of accident, and other factors. In addition, special attention must also paid to potential accidents which might in underground excavations, including unstable facing phenomena (such as collapse and swelling of facing at weak layer sections), spring water flow resulting collapse of rock, gas eruption, and rock burst. While considering these factors to be emphasized during the construction of geological disposal facilities, the investigation reviewed the existing working methods on individual construction technologies ...
For the construction of underground facilities comprising access tunnels, connecting tunnels, main tunnels and disposal tunnels, a large number of tunnels will be excavated in deep rock formations. These excavations will extend hundreds kilometers in total length. Therefore, special attention must be paid, to transporting large volume of debris, ventilation, emergency escape routes in case of accident, and other factors. In addition, special attention must also paid to potential accidents which might in underground excavations, including unstable facing phenomena (such as collapse and swelling of facing at weak layer sections), spring water flow resulting collapse of rock, gas eruption, and rock burst. While considering these factors to be emphasized during the construction of geological disposal facilities, the investigation reviewed the existing working methods on individual construction technologies ...
Object: To control the average liquid level of each steam generator at a constant level irrespective of the flow rate of sodium thereby to decrease change in the retained amount of sodium and at the same time to improve the load response characteristic. Construction: A method for decreasing to as large an extent as possible a change in the amount of sodium retained in a steam generator due to change in the flow rate, which comprises the steps of detecting the main recirculating flow rate of liquid sodium by the use of a sodium flow rate detector, amplifying the detected flow rate signal depending upon the ratio between the flow rates respectively in a super-heater and a re-heater (distribution ratio), delivering the amplified signal to a function generator which generates a liquid level setting signal for maintaining the respective average ...
Consider the flow of a thin layer of non-Newtonian fluid over a solid surface. I model the case of a viscosity that depends nonlinearly on the shear-rate; power law fluids are an important example, but the analysis here is for general nonlinear dependence. The modelling allows for large changes in film thickness provided the changes occur over a large enough lateral length scale. Modifying the surface boundary condition for tangential stress forms an accessible base for the analysis where flow with constant shear is a neutral critical mode, in addition to a mode representing conservation of fluid. Perturbatively removing the modification then constructs a model for the coupled dynamics of the fluid depth and the lateral momentum. For example, the results model the dynamics of gravity currents of non-Newtonian fluids even when the flow is not very slow.
Currently the construction of small-scale hydroelectric and pumped storage plants is booming in the USA. The technology is attractive because of its relatively cheap construction methods and operation. Electric utilities are seeing it as a viable source of peaking power and a means of system regulation. Two schemes are described. One is a high-head/small flow river project designed to generate 3.5 MW and is about to come on line having overcome tight environmental and commercial constraints. The second is a pumped-storage project using two man-made reservoirs with an average elevation difference of 1280 ft. It is deemed to be of minimum environmental impact construction and good physical characteristics. Completion is hoped for by 1995 and the plant will deliver 1000 MW. (UK)
Experimental wetlands are being constructed on mined lands in the United States as an inexpensive alternative to conventional acid mine water treatment facilities. The US Bureau of Mines is conducting an inventory of these constructed wetlands as part of a long-term evaluative study. Preliminary results, based on the 20 sites surveyed to date, indicate that the wetlands dominated by emergent species are out-performing the Sphagnum-dominated wetlands, and that much of the water treatment is accomplished by other aspects of the wetland, including bacteria, algae, amendments and other plants. Iron concentrations as high as 85 mg/l are reduced to less than 3 mg/l after flow through the constructed wetlands. Manganese is also removed, though somewhat less efficiently. 12 refs., 1 fig., 1 tab.
Mixed carbide fueled driver assembly experiments will be tested in FFTF fuel driver positions as part of the National Advanced Fuel Program. The design of the experiment flow ducts must assure conformance to FFTF functional requirements in addition to service as a test vehicle for the carbide fuel irradiations. Test goals of damage fluence burnup, and fluence to burnup ratio exceed those of the standard oxide fueled drivers. As a consequence, the 20% cold worked type 316 stainless steel material of construction will experience significant irradiation induced creep and swelling. Additionally, the flow duct design must withstand the enhanced thermal transients produced by the action of carbide fuel during reactor scrams. A major FFTF functional requirement is that adjacent flow ducts do not touch each other except at the load pads. This requires a realistic analysis of the creep and swelling deformation ...
In the design of LWRs, the forecast of critical heat flux (CHF) is important. The existing CHF correlation equations include the arbitrary constants based on experimental data, therefore, their range of application is limited. For advancing the research and development of high conversion LWRs or passive safety reactors, the development of more general CHF forecasting technique has been demanded. In order to elucidate the mechanism of CHF occurrence and construct the general forecasting model based on physical phenomena, the detailed observation of flow phenomena near a heat generation surface is indispensable. The experiment of observing boiling two-phase flow and CHF phenomena by applying neutron radiography technique was carried out. The utilization of neutron radiography in the field of heat-transferring flow is explained. The experimental setup and the experimental method, the experimental ...
An experimental study of the hydrodynamics of a narrow channel was performed in order to obtain the heat transfer mechanisms and influences contributing to the flow regime transition from inverted annular to inverted slug flows for post dryout downflow. The experimental series consisted of both adiabatic and diabatic visualization tests over a wide range of fluid and thermal parameters. The system inlet gas velocities ranged from 0 to 14 meters per second while the inlet fluid velocities ranged from 1 to 3 meters per second. Full extent visualization of the flow regime was possible due to a quartz tube in tube construction with a clear heating fluid. Constant temperature heating of the freon was accomplished at bulk fluid temperatures above the critical heat flux temperature. For each hydrodynamic flow condition, one to three minuets of VHS-video filming was performed to acquire ...
Energy savings performance contracting (ESPC) is now receiving greater attention as a means of implementing large-scale energy conservation projects in housing. Opportunities for such projects exist for military housing, federally subsidized low-income housing, and planned communities (condominiums, townhomes, senior centers), to name a few. Accurate prior (to construction) estimates of the energy savings in these projects reduce risk, decrease financing costs, and help avoid post-construction disputes over performance contract baseline adjustments. This paper demonstrates an improved method of estimating energy savings before construction takes place. Using an engineering model calibrated to pre-construction energy-use data collected in the field, this method is able to predict actual energy savings to a high degree of accuracy. This is verified with post-construction energy-use ...
Energy savings performance contracting (ESPC) is now receiving greater attention as a means of implementing large-scale energy conservation projects in housing. Opportunities for such projects exist for military housing, federally subsidized low-income housing, and planned communities (condominiums, townhomes, senior centers), to name a few. Accurate prior (to construction) estimates of the energy savings in these projects reduce risk, decrease financing costs, and help avoid post-construction disputes over performance contract baseline adjustments. This paper demonstrates an improved method of estimating energy savings before construction takes place. Using an engineering model calibrated to pre-construction energy-use data collected in the field, this method is able to predict actual energy savings to a high degree of accuracy. This is verified with post-construction energy-use ...
Using a coplanar, end-mounted antenna as a baseline, various configuration trades were performed to select a preferred solid state concept. The increase in efficiency that could be realized by use of multi bandgap solar cells, either with klystron or solid state antenna was evaluated. Satellite configurations were developed to exploit the sandwich antenna concept wherein solar cells are located on one side of the antenna panel and solid state dc/RF converters on the other side. These concepts entailed various primary and secondary reflector arrangements for directing solar energy to the solar cell side of the antenna with higher concentration ratios than used on the coplanar configurations. Operations analysis included development of a satellite construction scenario, a concept for the SCB, a top-level satellite construction operation, construction operation, construction timelines and crew sizes, mass ...
This comprehensive final report for the Swiss Federal Office of Energy (SFOE) examines ways to optimise energy flows in mains networks that include distributed generation facilities. Increasing use of decentralised generation, its effects on the operation of low-voltage mains and the efficient use of the 400 V mains is discussed. The principles of operation and construction of controlled storage installations are discussed and concrete examples of their use in both grid-connected and island operation are quoted. Alternatives to storage are looked at from both the technical and economic points of view. The storage technologies used such as flywheels, supercaps, redox-flow batteries and lead-acid accumulators are briefly assessed and the results of simulations are discussed.
A nonlinear free boundary-value problem of supercavitating flow past n + 1 hydrofoils is analyzed. To describe the cavities' closure mechanism, the Tulin-Terentev single-spiral-vortex model is employed. The flow domain is considered as the image of an (n + 1)-connected circular domain. The conformal map is constructed in terms of the solutions to two Riemann-Hilbert problems of the theory of symmetric automorphic functions. One of the problems is homogeneous and its coefficients are continuous functions while the second problem is inhomogeneous and has discontinuous coefficients. The exact solutions to the problems are found by using quasiautomorphic and quasimultiplicative analogs of the Cauchy kernel. The case of a single plate is considered in detail and the numerical results are report...
A mathematical and physical model was constructed describing the hydrodynamics of the two-phase mixture in the horizontal steam generator. The HP 9830 A desk-top calculator was used for the computations. The output variable of the solution was the level shape. A quantitative and qualitative comparison was made of the results of computations and experimental data. (author).
Two-phase flow, thermal management systems are currently being considered as an alternative to conventional, single phase systems for future space missions because of their potential to reduce overall system mass, size, and pumping power requirements. Knowledge of flow regime transitions, heat transfer characteristics, and pressure drop correlations is necessary to design and develop two-phase systems. This work is concerned with microgravity, two-phase flow regime analysis. The data come from a recent sets of experiments. The experiments were funded by NASA Johnson Space Center (JSC) and conducted by NASA JSC with Texas A M University. The experiment was on loan to NASA JSC from Foster-Miller, Inc., who constructed it with funding from the Air Force Phillips Laboratory. The experiment used R12 as the working fluid. A Foster-Miller two phase pump was used to circulate the two phase mixture and allow ...
Two-phase flow, thermal management systems are currently being considered as an alternative to conventional, single phase systems for future space missions because of their potential to reduce overall system mass, size, and pumping power requirements. Knowledge of flow regime transitions, heat transfer characteristics, and pressure drop correlations is necessary to design and develop two-phase systems. This work is concerned with microgravity, two-phase flow regime analysis. The data come from a recent sets of experiments. The experiments were funded by NASA Johnson Space Center (JSC) and conducted by NASA JSC with Texas A ampersand M University. The experiment was on loan to NASA JSC from Foster-Miller, Inc., who constructed it with funding from the Air Force Phillips Laboratory. The experiment used R12 as the working fluid. A Foster-Miller two phase pump was used to circulate the two phase mixture and ...
On 24th of July 2007 Westinghouse Electric Co. signed landmark contracts with China's State Nuclear Power Technology Corporation (SNPTC), to provide four AP1000 nuclear power plants in China. The AP1000 is a two-loop 1117 MWe Pressurized Water Reactor (PWR). It is based on proven technology, but with an emphasis on safety features that rely on natural driving forces, such as pressurized gas, gravity flow, natural circulation flow and convection. Ansaldo Nucleare has provided a significant support to the passive plant technology development and, starting from 2000, is cooperating with Westinghouse to development of the AP1000 Plant. In the frame of the AP1000 Chinese agreement, Ansaldo Nucleare, in Joint Venture with Mangiarotti Nuclear, has signed a contract with Westinghouse for the design and the supply of innovative components to be installed in the first AP1000 unit to be constructed at the Sanmen site. The contract ...
An experimental investigation of a humidification-dehumidification desalination (HDD) process using solar energy at the weather conditions of Suez City, Egypt, is presented. A test rig is designed and constructed to conduct this investigation under different environmental and operating conditions. The test rig consists of a solar water heater (concentrator solar collector type), solar air heater (flat plate solar collector type), humidifier tower and dehumidifier exchanger. Different variables are examined including the feed water flow rate, the air flow rate, the cooling water flow rate in the dehumidifier and the weather conditions. Comparisons between the experimental results and other published results are presented. It is found that the results of the developed mathematical model by the same authors are in good agreement with the experimental results. The tested results show that the productivity ...
An experimental investigation of a humidification-dehumidification desalination (HDD) process using solar energy at the weather conditions of Suez City, Egypt, is presented. A test rig is designed and constructed to conduct this investigation under different environmental and operating conditions. The test rig consists of a solar water heater (concentrator solar collector type), solar air heater (flat plate solar collector type), humidifier tower and dehumidifier exchanger. Different variables are examined including the feed water flow rate, the air flow rate, the cooling water flow rate in the dehumidifier and the weather conditions. Comparisons between the experimental results and other published results are presented. It is found that the results of the developed mathematical model by the same authors are in good agreement with the experimental results. The tested results show that the productivity ...
An experimental investigation of a humidification-dehumidification desalination (HDD) process using solar energy at the weather conditions of Suez City, Egypt, is presented. A test rig is designed and constructed to conduct this investigation under different environmental and operating conditions. The test rig consists of a solar water heater (concentrator solar collector type), solar air heater (flat plate solar collector type), humidifier tower and dehumidifier exchanger. Different variables are examined including the feed water flow rate, the air flow rate, the cooling water flow rate in the dehumidifier and the weather conditions. Comparisons between the experimental results and other published results are presented. It is found that the results of the developed mathematical model by the same authors are in good agreement with the experimental results. The tested results show that the productivity ...
A study was conducted to predict indoor ventilation, smoke movement and fire propagation in a new building currently under construction at the Ecole Polytechnique de Montreal. It was conducted in response to concerns regarding the impact that air quality, in normal operation conditions, and smoke concentration, in the event of a fire, may have on occupants of a building. A detailed three-dimensional model of the new building was constructed using the NURBS-based modeler, Rhino. Simulations of fire propagation and airflow ventilation were performed in different areas of the building. The flow pattern data was analyzed using the computational fluid dynamics (CFD) program called FLUENT. It predicted air flow conditions and estimated the mean age of air (MAA) in the room. Real-world geometries, such as diffuser inlets, have a significant impact on overall fluid flow behaviour and are ...
Plasma arc welding processes are used in off-shore industry for construction and maintenance in the wet surrounding of underwater structures and pipelines. In greater water depth the density of the plasma gas increase because of the greater hydrostatic pressure. This causes the increase of conductive heat losses to the wet surrounding. To keep up the energy flux to the workpiece to be welded, the plasma arc has to burn in a local dry area with an inside pressure of 1 bar. This requirement can be fulfilled by a rotating cylinder with a liquid film flowing down the inner wall. The flow around the rotating cylinder to create a local dry area around the plasma arc under water is experimentally investigated. The rotating cylinder is placed above the work surface which is simulated by a flat plate. According to the centrifugal forces of the rotating flow inside the gap between the lower end of the cylinder ...
This report documents a one-dimensional numerical model, SAMFT1D, developed to simulate single-phase and multiphase fluid flow and solute transport in variably saturated porous media. The formulation of the governing equations and the numerical procedures used in the code for single-phase and multiphase flow and transport are presented. The code is constructed to handle single-phase as well as two or three-phase flow conditions using two integrated sets of computational modules. The fully implicit scheme is used in the code for both single-phase and multiphase flow simulations. Either the Crank-Nicholson scheme or the fully implicit scheme may be used in the transport simulation. The single-phase modules employ the Galerkin and upstream weighted residual finite element techniques to model flow and transport of water (aqueous phase) containing dissolved ...
Theoretical and experimental research efforts in evaluating an innovative concept for vertical axis wind turbines (VAWT) are described. The concept is that of using straight blades composed of circulation controlled airfoil sections. The theoretical analysis has been developed to determine the unsteady lift and moment characteristics of multiple-blade cross-flow wind turbines. To determine the drag data needed as input to the theoretical analysis, an outdoor test model VAWT has been constructed; design details, instrumentation, and calibration results are reported. Initial testing is with fixed pitch blades having cross-sections of conventional symmetrical airfoils. Costs of building the test model are included, as well as estimates for blades constructed with composite materials. These costs are compared with those of other types of wind turbines.
Background, aim and scope Treatment performance of constructed wetlands (CWs) is largely dependent on the characteristics of the wastewater. Although livestock wastewater is readily biodegradable in general, its variety in biodegradability can still be significant in practice. In addition, it is a common practice to periodically use disinfectants in livestock activities for health concerns. Obviously, the residual of the disinfectants in livestock wastewater may have serious inhibitory effect on the microbial activities during wastewater treatment. Thus, the main objective of this study was to examine the variety of livestock wastewater in biodegradability and its effect on the performance of a pilot scale tidal flow CWs (TFCWs) in organic matter and nitrogen removal. Furthermore, investig...
A Process for yellow cake production from local Euxenite was developed in Bench Scale by using sulphuric acid digestion with simultaneously ion-exchange and solvent extraction purification steps. Uranium was then precipitated as uranium diuranate by ammonia solution. Equipment used in this process includes : digestion vessels, columnar ion-exchange, solvent extraction and precipitation units Ore feed to the process could be adjusted up to 2 kilogram per day (8 hours operation) with yellow cake product purity meet the requirement of Usaec standard of about 10-50 gram per day. Included in this experiment are the leaching characteristics of the ore, the design and construction of continuous columnar 4-cycle ion exchange unit, determination of the extraction and stripping stages of a gravity flow mixer-settler and the design and construction of continuous yellow cake precipitation unit with large grain size and high density ...
Full text of publication follows: As the coolant experiences no phase change in the core, SCWRs, unlike LWRs, cannot use design criteria based on the critical heat flux concept. The commonly accepted practice in SCWRs is to specify cladding temperature limits that must be met during transient and accident events. Therefore for the design of the SCWR, it is very important to predict the heat transfer coefficient to the supercritical water coolant with great accuracy. Our recent study focuses on the critical issue of measuring heat transfer to supercritical water at prototypical SCWR conditions and to develop the tools to predict the SCWR thermal behavior. A heat transfer test loop using a surrogate fluids, CO_2, is under construction. The reason of using CO_2 instead of water is that (i) valuable insight of the physical phenomena can be obtained with this fluid, and (ii) some existing facilities already used surrogate fluids, which in general have lower critical ...
In order to practice design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, one of the immediate concerns is improvement in its predictive capability of boiling transition phenomena on the fuel rod surface. This capability strongly depends on the modeling of thermohydraulics phenomena of interests: 1) vapor-liquid redistribution by inter-subchannel exchanges due to the diversion cross flow, turbulent mixing and void drift, 2) liquid film behaviors, 3) transition of two-phase flow regimes, 4) droplet entrainment and deposition and 5) spacer-droplet interactions. These are considered to be five key factors in understanding the BT in BWR fuel rod bundles. This paper describes a progress and current status in the second year of the three year project on developing generalized boiling transition models with the above five key factors being focused on. A combined approach of ...
Real-time neutron radiography is being evaluated for studying the dynamic behavior of two-phase flow and for measuring void fraction in vertical and inclined water ducts. This technique provides a unique means of visualizing the behavior of fluid flow inside thick metal enclosures. An air-water flow system was constructed to simulate vapor conditions encountered in a fluid flow duct. Air was injected into the bottom of the duct at flow rates up to 0.47 {ell}/s (1 ft{sup 3}/min). The water flow rate was varied between 0 and 3.78 {ell}/min (0 to 1 gal/min). The experiments were performed at the Pennsylvania State University nuclear reactor facility using a real-time neutron radiography camera. With a thermal neutron flux on the order of 10{sup 6} n/cm{sup 2}{center_dot}s{sup {minus}1} directed through the thin duct dimension, the dynamic ...
Real-time neutron radiography is being evaluated for studying the dynamic behavior of two phase flow and for measuring void fraction in vertical and inclined water ducts. This technique provides a unique means of visualizing the behavior of fluid flow inside thick metal enclosures. To simulate vapor conditions encountered in a fluid flow duct, an air-water flow system was constructed. Air was injected into the bottom of the duct at flow rates up to 0.47 I/s (1 cfm). The water flow rate was varied between 0--3.78 I/m (0--1 gpm). The experiments were performed at the Pennsylvania State University nuclear reactor facility using a real-time neutron radiography camera. With a thermal neutron flux on the order of 10{sup 6}n/cm{sup 2}/s directed through the thin duct dimension, the dynamic behavior of the air bubbles was clearly visible through 5 ...
Real-time neutron radiography is being evaluated for studying the dynamic behavior of two-phase flow and for measuring void fraction in vertical and inclined water ducts. This technique provides a unique means of visualizing the behavior of fluid flow inside thick metal enclosures. An air-water flow system was constructed to simulate vapor conditions encountered in a fluid flow duct. Air was injected into the bottom of the duct at flow rates up to 0.47 ell/s (1 ft"3/min). The water flow rate was varied between 0 and 3.78 ell/min (0 to 1 gal/min). The experiments were performed at the Pennsylvania State University nuclear reactor facility using a real-time neutron radiography camera. With a thermal neutron flux on the order of 10"6 n/cm"2#centre dot#s"-"1 directed through the thin duct dimension, the dynamic behavior of the air bubbles was ...
This feature articles described a concept and technical problems of geological disposal of high-level radioactive waste in the civil engineering. It consists of six papers such as the present statues and subjects of geological disposal by KITAYAMA Kazumi, the diastrophism, igneous activity, and upheaval and erosion by YAMAZAKI Haruo, the groundwater flow and evaluation of nuclear transfer by IJIRI Yuji, evaluation of alteration of cement materials in the ultra-long period by HAGA Kazuko, The Mizunami Underground Research Laboratory in course of construction by SAKAMAKI Masanori, and interview of the ninetieth president of JSCE (Japan Society of Civil Engineers), he places his hope on JSCE and civil engineers by KISHI Kiyoshi. (S.Y.)
To encourage the application of robotics technology for routine radiobench applications, a laboratory dedicated to the research and development of contained robotic systems is being constructed. The facility will have several robots located in laminar flow hoods, and the hoods are being designed to allow the possibility for multiple robots to work together. This paper presents both the design features of the hoods and the general layout of the laboratory, and also discusses an application of a robotic system for the routine nuclear counting of gamma tube samples. The gamma tube system is presently operating in one of the routine analysis laboratories. 5 figs.
With the compensator-series equipment put into operation in 1992 - giving a performance of 330 Mvar - it was made possible for high-performance electronics to use a continuously variable, fully loaded power transmission line and to regulate the energy flow and minimise overcurrent losses. As well as these technical qualities, this system could offer environmental advantages for European implementation. This would avoid the need to plan and construct new high voltage transmission lines in order to meet increased demand. (orig.)
This paper details the design, construction and testing of a bayonet tube heat exchanger for use in the process industry and potentially as part of an externally fired combined cycle. Detailed analysis of the system has been undertaken, in particular on the tube side. The data is reported in terms of temperature, pressure, heat gain and heat exchanger effectiveness, over a range of Reynolds numbers and shell side mixture ratios. Much of the heat gained by the tubes is in the annular flow of the bayonet tube. Overall the effectiveness of this system could exceed 70%. (Author)
Long steam turbine blades are always made as massive blades cut from the solid. For a given blade material and given rotational speed of the steam turbine, the maximum permissible blade length depends on a tapering factor which expresses the ratio of the centrifugal force of the real blade, always twisted and tapered, to the centrifugal force of the theoretical cylindrical blade of the same flow cross-section. This factor can be further reduced to a considerable degree, due to a better approximation to the shape having uniform srength, if the blade is constructed as a hollow blade. (orig./LH).
In coke-oven operations flue-gas valves are used to switch the regenerator function from rich gas firing to lean gas firing. Compared with the simple geometry of the other parts of the flow path, which comprise flues and regenerators, the narrow and winding passages of the flue-gas valves give rise to relatively high losses in pressure. Without the construction of high (and therefore expensive) chimneys, this means that operating problems may well arise due the inadequate suction capacity. The project focused on the theoretical and experimental analysis of a coke-oven flue-gas valve. The primary aim was to reduce the pressure drop through the valve without modifying its external geomerty. The internal flow characteristics created by different valve geometries under a variety of operating conditions were simulated using the commercial CFD code Fluent/UNS, which provided velocity and pressure distributions. A half-scale model ...
This paper summarizes substance flow analyses for four organic substances in the City of Stockholm, Sweden: diethylhexyl phthalate (DEHP), alkylphenolethoxylates (APEO), polybrominated diphenylethers (PBDE) and chlorinated paraffins (CP). The results indicate that the stocks of APEO, PBDE and CP all are approximately 200-250 tonnes, whereas the DEHP stock is two orders of magnitude larger. Emissions can be linked to imported consumer goods such as electronics (PBDE) and textiles (APEO), and to construction materials (DEHP, CP). For several of the substances considerable amounts remain in the technosphere for a long time, even after use of the substance in new products has been eliminated. For example, the use of DEHP as plasticizer for PVC plastics in cables and floorings has more or less been phased-out, but still these applications make up a stock of some 20,000 tonnes (85% of the total DEHP stock in Stockholm) and emit 28 tonnes of DEHP ...
Geological, geophysical, thermal, petrophysical and hydrological data available for the East Mesa hydrothermal system that are pertinent to the construction of a computer model of the natural flow of heat and fluid mass within the system are assembled and correlated. A conceptual model of the full system is developed and a subregion selected for quantitative modeling. By invoking the Boussinesq approximation, valid for describing the natural flow of heat and mass in a liquid hydrothermal system, it is found practical to carry computer simulations far enough in time to ensure that steady-state conditions are obtained. Initial calculations for an axisymmetric model approximating the system demonstrate that the vertical formation permeability of the deep East Mesa system must be very low (k/sub v/ approx. 0.25 to 0.5 md). Since subsurface temperature and surface heat flow data exhibit major deviations from ...
A one-way coupling system between the plant simulator TRAC/BF1-ENTREE and the subchannel code with the improved cross flow model, NASCA, has been developed. Based on a scenario of turbine trip tests in the Peach Bottom Unit 2, the wide and rapid reactivity insertion transient induced by the system pressure rise was calculated. The pin power distribution in hot bundles was re-constructed considering heterogeneity of the fuel bundle. When the neighboring control blade is withdrawn, NASCA predicted that the steady-state bundle exit void distribution was nearly flat with regardless of the pin power distribution. However, void distributions in the middle and lower bundle regions became complicated depending on the pin power and the two-phase flow regime in each subchannel. The pin power distribution rapidly changed according to traveling of control blades. However, influence in the void distribution was delayed and damped due to ...
This paper provides some results of the research works at low pressure components of steam turbines and some construction solutions resulting in a modernisation. The problems of turbine phases for the transonic flow are analysed with respect to reducing profile and margin losses. The origin and flow of wet steam and its influence on corrosion and erosion is investigated. Inlet and outlet casing of the flow channels and transfer diffuser between second last and last phase are mentioned. (orig.) [Deutsch] Im Beitrag werden einige Ergebnisse der Forschung der Teile von ND-Teilen der Dampfturbinen angegeben, und werden irgendeine Konstruktionsloesungen, die fuer ihre Modernisierung guenstig sind, beschrieben. Kurz wird die Problematik der Turbinenstufen fuer die transsonische Stroemung analysiert, mit Hinsicht auf die Erniederung der Profil- und Randverluste. Weiter ist die Aufmerksamkeit der Entstehung und ...
A copyrighted computational fluid dynamics computer code, ICOMFLO, has been developed for the simulation of multiphase reacting flows. The code solves conservation equations for gaseous species and droplets (or solid particles) of various sizes. General conservation laws, expressed by elliptic type partial differential equations, are used in conjunction with rate equations governing the mass, momentum, enthalpy, species, turbulent kinetic energy, and turbulent dissipation. Associated phenomenological submodels of the code include integral combustion, two parameter turbulence, particle evaporation, and interfacial submodels. A newly developed integral combustion submodel replacing an Arrhenius type differential reaction submodel has been implemented to improve numerical convergence and enhance numerical stability. A two parameter turbulence submodel is modified for both gas and solid phases. An evaporation submodel treats not only droplet evaporation but size ...
The five thermal-hydraulic concepts chosen for conceptual study of advanced PWR systems have been studied as follows: (1) Critical Heat Flux in passive PWR Conditions: review of previous works (various of correlations, analysis of parametric trends) on CHF, assessment and improvement of CHF prediction models for round tubes, development of the prediction model on bundle CHF with considering the correction factor calculated from the tube data base, design and construction of the intermediate-pressure CHF experimental loop, extension of CHF data base by performing the experiments at low-flow, and low-quality conditions (2) Passive Cooling Concepts for Concrete Containment Systems: Selection of the external condenser by comparing and reviewing between passive cooling concepts for concrete containment system concepts, survey and review of previous studies (theoretical mechanism of condensation heat transfer and effect of non-condensable gases) on ...
In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic modeling approach. They should include ...
Full text of publication follows:In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic ...
In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic modeling approach. They should include ...
This is the third quarterly progress report for Year 3 of the ACTS Project. It includes a review of progress made in: (1) Flow Loop construction and development and (2) research tasks during the period of time between Jan. 1, 2002 and Mar. 31, 2002. This report presents a review of progress on the following specific tasks: (a) Design and development of an Advanced Cuttings Transport Facility (Task 3: Addition of a Cuttings Injection/Separation System), (b) Research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (c) Research project (Task 9b): ''Study of Foam Flow Behavior Under EPET Conditions'', (d) Research project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (e) Research on three ...
The simulation of the Auxiliary Charcoal Bed (ACB) Vacuum System was performed to evaluate the original vacuum system design, detect and identify design deficiencies, investigate the effects of proposed corrections on system performance, and generally aid in refining the system design before construction and mockup testing. The simulation was performed by using the Advanced Continuous Simulation Language (ACSL). The vacuum system design goals are to provide approximately 20 SCFM of both booster gas and purge gas through the system and maintain a flow of approximately 40 SCFM with a velocity of 50 to 75 f/sec at the entrance to the cyclone separator. The model results showed that the original system design was incapable of meeting the system performance goals. Further simulations showed that the following modifications to the original vacuum system design were required to make the system performance acceptable; (1) Remove valve PCV4. (2) Modify ...
Pre-stacking depth migration treatment is studied for the estimation of the fold configuration from seismic survey cross sections. The estimation of a velocity structure is necessary for the execution of such treatment, and the utilization of structural-geological knowledge is required for its interpretation. The concept of balanced cross section in relation to the fault-bend fold constructs a stratum structure model under conditions that the deformation during fold and fault formation is a planar strain, that there is no change in volume due to deformation, and that a fold is a parallel fold. In addition to the above geometric and kinetic approach, there is another fold formation process simulation model using a Newtonian fluid for study from the viewpoint of dynamics. This simulation stands on the presumption that the boundary contains a ramp that had been in presence before fold formation and that an incompressible viscous matter is mounted on the top surface. ...
Construction of the French PWR nuclear program started in the early 70s, at the time a number of operating plants in the US were being affected by the first corrosion problems. Since, at that time, its construction program was in an early stage, FRAMATOME was able to make modifications on the first units to improve steam generator resistance to corrosion. For instance, full depth expansion of the tubes in the tube-sheet using an explosive process (Westex) was performed on Fessenheim 1 steam generators already installed on site. Later on, continuous operating experience was being obtained in the US, before startup of the French units. This allowed FRAMATOME to react rapidly and take immediate corrective actions at the design stage, during fabrication and sometimes even on site in order to mitigate the risk of corrosion in the steam generators. FRAMATOME is confident that the present design of its steam generator models, including a large number ...
To carry out studies on the radon behavior under controlled and stable conditions it was designed and constructed a system that consists of two parts: a container of mineral rich in Uranium and an experimentation chamber with radon united one to the other one by a step valve. The container of uranium mineral approximately contains 800 gr of uranium with a law of 0.28%; the radon gas emanated by the mineral is contained tightly by the container. When the valve opens up the radon gas it spreads to the radon experimental chamber; this contains 3 accesses that allow to install different types of detectors. The versatility of the system is exemplified with two experiments: 1. With the radon experimental chamber and an associated spectroscopic system, the radon and two of its decay products are identified. 2. The design of the system allows to couple the mineral container to other experimental geometries to demonstrate this fact it was coupled and proved a new automatic ...
In situ toxicity tests were designed for Ceriodaphnia dubia and Chironomus tentans as part of a larger study designed to assess the effectiveness of constructed wetlands for the treatment of wastewater produced by oil production at Suncor OSG. The artificial wetlands were 50m long by 3m wide, with three replicates of the control and the treatment. Each wetland had four sample sites equidistant along its length, creating a gradient of treatment from site A being the most toxic to site D being the least toxic. Each test was conducted twice during the summer of 1994. Both the Ceriodaphnia and Chironomus test cages were a flow through design to allow for maximal exposure to the water within the wetlands. Mortality and reproduction were used as endpoints for Ceriodaphnia, whereas mortality and growth were used as endpoints for the Chironomus test. Test durations were fifteen and ten days respectively. Chironomus had very high mortality along the ...
The radiative heat loss from a surface is determined by its total hemispherical emittance, which consequently plays an important role in aerospace and solar applications. This study compares emittances measured calorimetrically with values derived from near normal incidence spectral reflectance measurements. This optical derivation is based on a number of assumptions which limit the accuracy if not sufficiency fulfilled. These assumptions include sample specularity, a straybody character beyond the range of measurement, only small variations of emittance with temperature, and a perfectly smooth sample surface. The comparison of calorimetrically and optically derived emittance performed in this study not only quantifies the errors introduced by insufficient fulfillment of the assumptions but also identifies which assumption causes the dominant error. The calorimetric emissometer, constructed for this study and based on a heat flow sensor, was ...
As in all vehicles of this type, low weight and aerodynamic drag must be achieved without compromising safety, and in an extremely rugged structure. This has been done by using a chrome-molybdenum steel space-frame, surrounded by a Kevlar/foam sandwich body shell. The solar panel wing, which uses a laminar flow section to obtain low drag, does not tilt except when the vehicle is stationary. A high degree of redundancy is built into the vehicle; for example there are two motors and transmissions, the solar array is divided into seven parallel sub-arrays, and the power electronics is multiply redundant. Built entirely in the garage of a suburban house, the Australian Geographic Team Marsupial car cost less than US$50,000 to construct.
The Superphenix 750-MW (thermal), once-throughtype steam generators are the result of over 10 years of intensive research and development. Detailed design and manufacture of the components lasted from 1977 to 1982. The main difficulties encountered during the construction of these prototype units concerned: demonstration of satisfactory high-temperature properties of Alloy 800 tubes; proven resistance of tube welds to thermal fatigue and of structures and shells to sodium/ water reaction effects; prevention of the tube bundle to flow-induced vibration; necessity of manual welding of shells to prevent hot cracking hazards related to the boron content of the steel; and welding of heat exchange tubes. None of these difficulties, however, invalidated initial major design choices, but provided a wealth of technical and technological experience and knowledge for the steam generators of the future. Plans for the future include revision of the ...
Over the last few years, string theory has changed profoundly. Most importantly, novel duality relations have emerged which involve gauge theories of brane excitations on one side and various closed string backgrounds on the other. In this lecture, we introduce the fundamental ingredients of modern string theory and explain how they are modeled through 2D (boundary) conformal field theory. This so-called `microscopic description' of strings and branes is an active research area with new results ranging from the classification and construction of boundary conditions to studies of 2D renormalization group flows. We shall provide an overview of such developments before concluding the lecture with an extensive outlook on some research that is motivated by current problems in string theory. This includes investigations of non-rational and non-unitary conformal field theories.
Source Philippe (on the island of La Govave, near Haiti) is described in terms of climatic, sociological, agricultural and technical background. Because of drought conditions, it became necessary to develop a solar still to provide the town with sufficient fresh water. The still, which has been in operation since 1969, is described in some detail as is the construction process. Brackish and sea water are used to produce more than 1250 liters of fresh water each day. A windmill is used to pump the brackish water from a well to an elevated storage tank; it flows by gravity to solar still basins where it is vaporized, then condensed on a sloping glass surface and collected. Benefits of the solar still to the town's economy and health are discussed. Cost of the project was $17,000. 10 references. (MJJ)
Ground-water monitoring near the Raft River site was initiated in 1974 by the IDWR. This effort consisted of semiannual chemical sampling of 22 irrigation wells near the Raft River geothermal development area. This program yielded useful baseline chemical data; however, several problems were inherent. For example, access to water pumped from the wells is limited to the irrigation season (April through September). All the wells are not continuously pumped; thus, some wells that are sampled one season cannot be sampled the next. In addition, information on well construction, completion, and production is often unreliable or not available. These data are to be supplemented by establishing a series of monitor wells in the proposed geothermal withdrawal and injection area. These wells were to be located and designed to provide data necessary for evaluating and predicting the impact of geothermal development on the Shallow Aquifer system.
SUMMARY We construct a new class of granular landslide models in which avalanches are simulated with large numbers of independent particles moving under the influence of topographically derived gravitational and centripetal acceleration. Concurrently, the particles suffer deceleration due to basal and dynamic friction. The novel aspect of the calculation is that complex particle-to-particle interactions, fluctuating basal contacts, and unresolved topographic roughness within and below the deforming flow are mimicked by random perturbations in along-track and cross-slope acceleration. We apply the method to the 1980 May 18 Mount Saint Helens debris avalanche by constraining the initial geometry and structure of the slide mass from geological data, and the initial failure sequence from eyewi...
Combined gas and steam turbine processes based on direct coal firing show a high thermal efficiency. At RWTH Aachen, University of Technology, an experimental test furnace has been built to investigate the pressurized pulverized coal combustion (PPCC). The PPCC-facility has been constructed as a slag tap furnace. Particles hitting the walls at temperatures above the melting point cause slagging depositions and create a film flowing down the reactor walls. As a part of the PPCC-program different mathematical models have been developed and implemented into the CFD-code FLUENT to predict the behavior of slag films at the furnace walls. Numerical strategies and the mathematical models used are described in detail. 12 refs., 9 figs.
Oil and gas production and processing operations sometimes cause naturally occurring radioactive materials (NORM) to accumulate at elevated concentrations in by-product waste streams. The sources of most of the radioactivity are isotopes of "2"3"8U and "2"3"2Th series, which are naturally present in the subsurface formations from which oil and gas are produced. NORM waste may cause problems in the operations of installations by plugging perforations, clogging tubular and valves then restricting flow. Therefore, plants or equipment have to be refurbished and decontaminated before reuse to avoid radioactive waste or surface contaminated object. There are two options for safe disposal of scale and sludge produced from NORM Descaling Facility : 1- Injection into an abandoned production well. 2- The construction of a near surface depository. These options are assumed to be environmental friendly disposal options. (author)
The hydro cyclone is a piece of equipment for separating and/or classifying solids/liquids with a wide variety of applications in different industrial sectors. This article describes the construction and operation of a hydro cyclone to verify the influence of the main size parameters and variables on its concentrating behaviour. The industrial-sized model which was built does not correspond exactly to the engineering designs. During operation, there was a load loss, which did not exceed 30 kPa, as a results of the fact that the suspension flow was unable to circulate with the original dimensions. However, when, for various reasons, the lower diameter was reduced, it proved possible to achieve an efficiency rate of over 95% in the concentration circuit. (Author) 23 refs.
A 46.3-ft-dia 20-degree conical ribbon parachute has been designed to retard a 2200-lb payload delivered at speeds up to 800 KCAS and at altitudes as low as 150 feet above ground level. The parachute uses both Kevlar and nylon materials, some of which were developed specifically for this parachute. The canopy design incorporates a patented construction geometry to minimize stress concentrations. A cluster of three 3.8-ft-dia ribbon parachutes is used to deploy the main parachute in the presence of severe aircraft flow field effects and large payload angles of attack. The results of over 30 full-scale flight tests indicate that fundamental limitations imposed by the dynamics of the air masses inside and behind the canopy determine the ultimate performance of a single large parachute when it is used at a release altitude of 150 ft.
Thirteen summaries of exploratory development work carried out under a grant to the Naval Postgraduate School Research Foundation are included. This research was carried out in the areas of electrical engineering (slot lines; phase lock loops), aeronautics (aircraft survivability; composite materials for structures), material sciences (relation between high temperature compressive behavior and microstructure), mechanical engineering (fatigue life of ferrocement hull structures; flow fields), economics (hazardous employment incentives for DoD personnel), operations research (missile allocation modeling; combat dynamics; shipboard tank designs), oceanography breakwater construction effects on ecology), and physics (evaluation of an underwater acoustic parametric source).
BACKGROUND.The National Breast and Cervical Cancer Early Detection Program (NBCCEDP) covers the direct clinical costs of breast and cervical cancer screening and diagnostic follow-up for medically underserved, low-income women. Personal costs are not covered. In this report, the authors estimated personal costs per woman participating in NBCCEDP mammography screening by race/ethnicity and also estimated lifetime personal costs (ages 50-74 years).METHODS.A decision analysis model was constructed and parameterized by using empiric data from a retrospective cohort survey of mammography rescreening among women ages 50 years to 64 years who participated in the NBCCEDP. Data from 1870 women were collected from 1999 to 2000. The model simulated the flow of resources incurred by a woman participat...
Electric utilities have been surprised by recent opposition to the construction of very-high-voltage transmission lines, which met with little resistance in the past. Concerns over health and safety factors are associated with the increase in the number of such lines, although their presence has always been an inconvenience and a hazard for those living and working in the immediate vicinity. The new lines present additional hazards due to the continuous flow of small electric currents and the charges that build up in the area of the towers and lines. The lines are also a threat to persons wearing cardiac pacemakers. There is experimental evidence from the Soviet Union and the U.S. that electric and magnetic fields at the frequencies of such power lines can have serious biological effects on growth rates and the functioning of the central nervous system. Full disclosure that possible risks are involved and the opportunity to avoid these risks is ...
A mathematical model has been constructed to describe the creation and filling of thermoluminescence traps during irradiation. Processes considered include trap filling, recombinations both between free charges and between free and trapped charges and thermal de-trapping. Also a simple trap creation term, linear with dose, has been included. A computer program has been written in order to solve the system of differential equations describing the various charge carrier flows during irradiation. The model and the program are described and the results of the application of the model to some simple energy-level schemes are discussed. Thermal de-trapping and band-to-band recombinations can introduce a dose rate dependence into the accumulation of trapped charge, whilst trap creation leads to the supralinear growth of charge trapped at certain defects with increasing dose.
We obtain an elegant and useful description of the dynamics of Szekeres dust models (in their full generality) by means of "quasi--local" scalar variables constructed by suitable integral distributions that can be interpreted as weighed proper volume averages of the local covariant scalars. In terms of these variables, the field equations and basic physical and geometric quantities are formally identical to their corresponding expressions in the spherically symmetric LTB dust models. Since we can map every Szekeres model to a unique LTB model, rigorous results valid for the latter models can be readily generalized to a non--spherical Szekeres geometry. The new variables lead naturally to an initial value formulation in which all scalars are expressed as scaling laws in terms of their values at an arbitrary initial space slice. These variables also yield a significant simplification of numerical work, since the fluid flow evolution equations ...
Staggered arrays of dimples printed on opposite surfaces of a cooling channel is formulated numerically and optimized with hybrid multi-objective evolutionary algorithm and Pareto optimal front. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing, and dimple depth, to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-means clustering technique and some of the clustered points were evaluated by ...
Staggered arrays of dimples printed on opposite surfaces of a cooling channel is formulated numerically and optimized with hybrid multi-objective evolutionary algorithm and Pareto optimal front. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing, and dimple depth, to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-means clustering technique and some of the clustered points were evaluated by ...
High temperature deformation behavior of AZ31 Mg alloy was investigated in this study on the basis of a processing map ({epsilon} {approx} 0.6). To construct a processing map, compression tests were carried out at various temperatures and strain rates. Two regions of high deformation efficiency ({eta}) were identified as: (1) a dynamic recrystallization (DRX) domain at 250 C and 1/s and (2) a superplasticity domain at 450 C and 10{sup -4}/s. The average grain size observed in the DRX region was considerably smaller (2.9{mu}m) than in any other region. In the superplastic condition, tensile elongation to failure approached to 1040%. At the high Z regions, flow softening occurred resulting from the dynamic recrystallization but below 10{sup 10} of Z value, flow hardening occurred due to the grain growth. Possible deformation mechanisms operating at high temperature were discussed in relation to the activation energy. A ...
Proof-of-principle experiments are reported for a new concept in electrically rechargeable zinc-air battery. The zinc electrode is a porous flow-thru type using a copper foam metal substrate with zinc deposition onto the foam metal from concentrated zincate electrolyte (as used in zinc-slurry type batteries). The bifunctional air electrode employs low-cost materials, being fabricated entirely from carbon-based precursors and small amounts of nickel and/or cobalt oxide. Corrosion measurements on the graphite materials in the air electrode indicate sufficient corrosion resistance for 8000 h life on charge. A prototype single cell was constructed having 1.5 Ah capacity producing 1.2 V discharge -2.0 charge at the three hour rate and has produced stable voltages for more than 150 cycles. Based on the 1.5 Ah prototype characteristics, design calculations for a 32 kWh battery project an energy density of about 110 Wh/kg, peak power density of 140 ...
The current situation in the development of nuclear power in the world and in Czechoslovakia is briefly outlined and the possibilities are discussed of alternative energy resources. The environmental impact is described of conventional power plants firing coal; sulphur and nitrogen oxides are mentioned and their environmental impacts shown. Their quantities and the quantities of other gaseous, liquid and soid wastes produced by coal power plants are given. Annual estimates are presented of radioactive material emissions; trace amount emissions of toxic metals and their ecological risks are shown. Concern over the increasing concentration of CO_2 in the atmosphere is voiced. For nuclear power plants, the amount of radionuclides in stack emission and of those released into water flows is tabulated. Their effect on the aqueous ecosystem is characterized as is thermal pollution of water flows and the environmental impact of cooling towers. Other ...
Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK) are promoting construction plan of Material-Life Science Facility, which is consisted of Muon Science Facility and Neutron Scattering Facility, in order to open up the new science fields. The Neutron Scattering Facility will be utilized for advanced fields of Material and Life science using high intensity neutrons generated by the spallation reaction induced by injecting a 1 MW pulsed proton beam onto a mercury target. Design of the spallation mercury target system is in progress to obtain good neutron performance keeping high reliability and safety. The target material is mercury. As a result of the spallation reaction, large amount of radioactive spallation products are to be contained in the mercury. Therefore to establish the safety of the target system, transient behaviors of the system during anticipated events should be well understood. The safety ...
... of drag measurements with the AGARD Nozzle Afterbody ... are discussed separately from flows with a ... bubbles introduce typical flow phenomena that ...
... 65th AGARD Fluid Dynamics Symposium, Madrid, Spain, October ... of research programs on flow control ... separation, and delta wing flows formed the ...
... Construction, Geology, and Aquifer Testing of the Maalo ... 8-98) Prescribed by ANSI Std Z39-18 Page 3. Construction, Geology, and Aquifer Testing ...
impflrtant to the understanding of complex vortical flows. ... tions like the slender wing, flow separations are controlled in the s,. ...... 10, AGARD LS-121, Dec. ...
This paper proposes an integrated method for using experimental data and CFD modeling to develop engineering correlations for atrium smoke management. Part I focused on the experimental program and validation of a CFD model of the experimental facility. Part II describes the extension of this model to a parametric study of balcony spill plumes. Smoke management in buildings during fire events often uses mechanical ventilation systems to maintain smoke layer elevation above a safe evacuation path. Design of these systems requires accurate correlations for the smoke production or mass flow rate of the buoyant fire plume. One design issue is the mass flow rate of fire plumes which spill out from a fire compartment, under a balcony and up through an atrium or other large volume. Current engineering correlations for these balcony spill plumes (BSPs) are based on a combination of one-tenth scale test data and theoretical analysis. The suitability of ...
This paper proposes an integrated method for using experimental data and CFD modeling to develop engineering correlations for atrium smoke management. Part I focused on the experimental program and validation of a CFD model of the experimental facility. Part II describes the extension of this model to a parametric study of balcony spill plumes. Smoke management in buildings during fire events often uses mechanical ventilation systems to maintain smoke layer elevation above a safe evacuation path. Design of these systems requires accurate correlations for the smoke production or mass flow rate of the buoyant fire plume. One design issue is the mass flow rate of fire plumes which spill out from a fire compartment, under a balcony and up through an atrium or other large volume. Current engineering correlations for these balcony spill plumes (BSPs) are based on a combination of one-tenth scale test data and theoretical analysis. The suitability of ...
The objective of this manuscript is to fully derive a geophysical multiphase model able to ''accommodate'' different multiphase turbulence approaches; viz., the Reynolds Averaged Navier-Stokes (RANS), the Large Eddy Simulation (LES), or hybrid RANSLES. This manuscript is the first part of a larger geophysical multiphase project--lead by LANL--that aims to develop comprehensive modeling tools for large-scale, atmospheric, transient-buoyancy dusty jets and plume (e.g., plinian clouds, nuclear ''mushrooms'', ''supercell'' forest fire plumes) and for boundary-dominated geophysical multiphase gravity currents (e.g., dusty surges, diluted pyroclastic flows, dusty gravity currents in street canyons). LES is a partially deterministic approach constructed on either a spatial- or a temporal-separation between the large and small scales of the ...
The Supercritical Water Cooled Reactor(SCWR) operates in a pressure around 25MPa and temperature of 293#approx#510 .deg. C. In order to study the heat transfer behaviors and good comparisons between the various fluids, a heat transfer test loop(SPHINX) using CO_2 has been constructed in KAERI as a part of international research program, I-NERI. At a supercritical pressure, the heat transfer coefficient is much larger than that estimated from the Dittus-Boelter correlation for a relatively large flow rate with moderate wall heat flux conditions. This phenomenon was explained by the rapid variations of the physical properties near the wall with the temperature. On the contrary, the heat transfer becomes worse when the bulk fluid enthalpy is below the pseudo-critical enthalpy under a low flow rate with large heat flux conditions. This phenomenon is called 'deteriorated heat transfer', and which is explained as the modification ...
This document is a user`s manual for the Rn3D finite element code. Rn3D was developed to simulate gas flow and radon transport in variably saturated, nonisothermal porous media. The Rn3D model is applicable to a wide range of problems involving radon transport in soil because it can simulate either steady-state or transient flow and transport in one-, two- or three-dimensions (including radially symmetric two-dimensional problems). The porous materials may be heterogeneous and anisotropic. This manual describes all pertinent mathematics related to the governing, boundary, and constitutive equations of the model, as well as the development of the finite element equations used in the code. Instructions are given for constructing Rn3D input files and executing the code, as well as a description of all output files generated by the code. Five verification problems are given that test various aspects of code operation, complete ...
A fully implicit compositional simulator was written to predict the drawdown and buildup responses for a single well in a gas condensate reservoir. The model uses the Redlich-Kwong equation of state to compute fluid properties and to determine phase equilibrium. The accuracy of the model predictions in the two-phase flow regime is tested using the results of a steady-state theory developed here. Two new correlating functions for transient flow - the reservoir integral and the sandface integral - are presented. The reservoir integral is shown to be a good liquid analogue during transient flow (drawdown). The sandface integral correlates with the liquid solution only in the slope. These two theoretical functions are shown to reduce to a computable pseudopressure function by using the results of the steady-state theory. The usefulness of this pseudopressure function for computing the permeability-thickness product and the skin ...
A membrane process utilizing dialysis and selective complexation by water-soluble polymers has been developed. This process, termed affinity dialysis, has been shown to be selectively extract and concentrate both cations and anions in a manner similar to ion exchange or solvent extraction. The selective removal of calcium from sodium with selectivity of about 30, removal of chromate ion from dilute streams, and separation of transition metal ions such as Cu/Fe and Cu/Zn have all been successfully demonstrated. Effects of different polymers, polymer concentration, temperature, and flow rates have been studied. The effect of increased polymer concentration is to increase product concentration if appropriate changes in feed, polymer solution, and strip flow rates are made. A continuous polymer solution recycle and regeneration system has been constructed and operated with Cu/Zn and chromate/chloride feed streams. Removal of ...
Full text of publication follows: Different to the very simple class of homogeneous non-equilibrium models (HEM) an one dimensional thermal-hydraulic theoretical drift-flux based and thus non-homogeneous coolant channel model and, as a result, an in itself complete thermal-hydraulic coolant channel module CCM have been established allowing to simulate in a very general way the steady state and transient behaviour of the most important parameters of a single- or two-phase fluid flowing within any type of heated or non-heated coolant channel (with an eventually varying cross flow area). To avoid mathematical discontinuities at the transition from single- to two-phase flow the coolant channel will, in its general form, be split into different regions, i.e. be looked as a basic channel (BC) which can consist of a number of different flow regimes and can, accordingly, be subdivided into a number of ...
This final report for the Swiss Federal Office of Energy looks at the possibilities for improved waste water utilization in the Lavey-les-Bains thermal spa, Switzerland. According to the regulations in force, the temperature of the waste water rejected into the Rhone river shall not exceed 30 {sup o}C, what is currently not the case. Also the operational cost shall be reduced and the waste water quality improved. The installations are presented. From the two geothermal wells, mineral water comes out at an average flow rate of 940 l/min and a temperature of 63 {sup o}C. Actual waste water data are reported. The measured thermal water consumption data, including seasonal variations, are analysed by computerized simulation and measures to reduce the consumed volume by the optimization of internal procedures are evaluated. Measures to reduce the quantity of the rejected free chlorine are discussed. Several possible adaptations of the existing space heating, domestic ...
This final report for the Swiss Federal Office of Energy looks at the possibilities for improved waste water utilization in the Lavey-les-Bains thermal spa, Switzerland. According to the regulations in force, the temperature of the waste water rejected into the Rhone river shall not exceed 30 "oC, what is currently not the case. Also the operational cost shall be reduced and the waste water quality improved. The installations are presented. From the two geothermal wells, mineral water comes out at an average flow rate of 940 l/min and a temperature of 63 "oC. Actual waste water data are reported. The measured thermal water consumption data, including seasonal variations, are analysed by computerized simulation and measures to reduce the consumed volume by the optimization of internal procedures are evaluated. Measures to reduce the quantity of the rejected free chlorine are discussed. Several possible adaptations of the existing space heating, domestic water ...
Within the framework of the EU power plant conceptual study (PPCS), helium-cooled modular divertor concepts have been investigated in detail at the Forschungszentrum Karlsruhe during the past few years. The first conceptual design proposed was based on convective cooling with the use of flow promoters in the form of pin and/or slot arrays (HEMP/HEMS) to increase the cooling surface and, hence, enhance the heat transfer capacity. While continuing the design optimisation, an advanced multiple-jet design (HEMJ) was introduced, which is based on direct jet-to-wall impinging cooling and offers advantages in terms of simple construction and manufacturing. Main emphasis of the 2004 work program (TW4-TRP-001) lay on experiments for the concepts HEMJ and HEMS, which were mainly performed at the Efremov Institute in St. Petersburg, Russia. For experiment preparation, detailed test programs were worked out and accompanying CFD analyses were accomplished. ...
Geological clay formations are investigated for use as final underground deposit for heat producing nuclear waste. Special kinds of clay (e.g. bentonite) can also be used for the construction of geotechnical barriers. For the long time safety prognosis of the nuclear waste repositories the development of geochemical transport models is indispensable. The transport of aqueous solutions in clay is a complex process. The three-layer-minerals bentonite and illite swell by the adsorption of water, if the volume is restricted a high swelling pressure develops. The excellent barrier effect of natural clay formations and geotechnical clay barriers is based on the high swelling pressure and the high adsorption capacity for radionuclides and other pollutants. The two-layer-mineral kaolinite has no swelling capacity. In contrast to sandy layers a special geochemical transport potential exists in clay besides the well known matrix potential which influences essentially the ...
This report has reviewed the construction of a cooling tower for the K reactor at the DOE Savannah River Site in Aiken, South Carolina. It has been found that the cooling tower would prevent further destruction of cypress and tupelo trees, would maintain a more consistent flow from site streams, and would allow earlier recovery of stream corridors inside a portion of the site. About 630 acres of wetlands have already been affected by the hot water discharged by the K reactor during the past 35 years. GAO believes that about 10 to 12 acres of additional damage would be prevented by the tower for every year the reactor is operated, and if current plans for re-start and retirement of the reactor are followed, less than 100 acres would be preserved. As requested, GAO also identified an example of a project that could be funded as compensation to the public for the damage the K reactor would do if Congress exempted it from the Clean Water Act and ...
We present moderate resolution spectroscopy of extraplanar diffuse ionized gas (EDIG) emission in the edge-on spiral galaxy NGC 4302. The spectra were obtained with the SparsePak integral field unit (IFU) at the WIYN Observatory. The spectra are used to construct position-velocity (PV) diagrams at several ranges of heights above the midplane. Azimuthal velocities are directly extracted from the PV diagrams using the envelope tracing method, and indicate an extremely steep dropoff in rotational velocity with increasing height, with magnitude ~30 km/s/kpc. We find evidence for a radial variation in the velocity gradient on the receding side. We have also performed artificial observations of galaxy models in an attempt to match the PV diagrams. The results of a statistical analysis also favor a gradient of ~30 km/s/kpc. We compare these results with an entirely ballistic model of disk-halo flow, and find a strong dichotomy between the observed ...
In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. Experimental design, and ...
Due to its important hydroelectric power generation facilities (about 525 plants with a total power of 13,314 MW producing about 35.3 TWh annually) Switzerland plays an important role in the interconnected European power system. Large artificial storage lakes in the Swiss Alps can generate peak power during hours of highest demand: 9700 MW are available from accumulated energy and the total power of pumped-storage facilities amounts to 1700 MW. The latter allow refilling the reservoirs at periods of low power demand and generating power at periods of peak demand. In the case of favorable conditions, the yearly average power production could be increased by 6% and the production during the winter period (October to March) by 20% by the year 2020. However, looking forward to the year 2050, the annual production is expected to decrease by 3% despite a possible extension of hydropower. This decrease is due to the enforcement of the minimum residual water flow rates ...
The goal of the Fifteenmile Creek Habitat Improvement project is to improve wild winter steelhead habitat in the Fifteenmile Creek Basin. This goal was addressed under the Columbia River Basin Fish and Wildlife Program, Measure 703 (c) (1) - Action Item 4.2. Construction of fish habitat structures was completed on approximately 3.5 miles of Eightmile Creek and on approximately 8.5 miles of Fifteenmile Creek. A total of 15,435 yds of rock was placed to improve rearing and spawning habitat, and to improve water quality and reduce siltation. Riparian protection fencing was completed on 1.8 miles of Dry Creek, approximately 1.75 miles on Eightmile Creek, and 4.75 miles on Fifteenmile Creek. Approximately 10 miles of stream will receive protection from the 8 miles of new fencing installed and 6.5 miles of abandoned fence repaired. Irrigation withdrawal screens were installed at six irrigation pump withdrawals. These screens functioned satisfactorily during the ...
As a three-year joint university-industry effort, development of a generalized boiling transition analysis method has been started in 2002 aiming at enhanced capabilities of subchannel analysis for a wide variety of BWR-type fuel bundle geometry from ordinary BWR to tight lattice fuel bundles. For this purpose, five dominant factors affecting boiling transition phenomena have been identified on which our efforts of experimentation and numerical analyses are focused. In this report, as the first-year achievement, we will describe a master plan of the development and contents for experimental approaches to construct thermal-hydraulic databases. The databases will be utilized for the developments of constitutive equations to describe the basic characteristics of the elementary processes. The planned experiments are divided into two groups. One is air-water experiments at atmospheric pressure, and the other is steam-water experiments up to 1 MPa. The former group of ...
As a three-year joint university-industry effort, development of a generalized boiling transition analysis method has been started in 2002 aiming at enhanced capabilities of subchannel analysis for a wide variety of BWR-type fuel bundle geometry from ordinary BWR to tight lattice fuel bundles. For this purpose, five dominant factors affecting boiling transition phenomena have been identified on which our efforts of experimentation and numerical analyses are focused. In this report, as the first-year achievement, we will describe a master plan of the development and contents for experimental approaches to construct thermal-hydraulic databases. The databases will be utilized for the developments of constitutive equations to describe the basic characteristics of the elementary processes. The planned experiments are divided into two groups. One is air-water experiments at atmospheric pressure, and the other is steam-water experiments up to 1 MPa. The former group of ...
There are certain factors to take into account when determining the suitability of a healthy house site. Power lines, agricultural spraying, vehicle exhaust, and industrial pollution are all potential sources of indoor air contamination. It is recommended that a environmental assessment be done to determine whether there are specific sources of contamination. Good drainage is required. The surrounding landscaping should be open and sunlit, and with low maintenance requirements. Decks and fences made from pressure-treated or chemical treated lumber should be avoided. One of the early decisions in the design process is the choice of the structural system. The key with all foundation types is to control moisture, whether from rain, from the ground, or the condensation of moisture from the air with cooling. The construction frame is sealed away from the occupants by the air/vapor barrier, so only in extreme cases is it essential to use alternatives to softwood lumber ...
Results from a heavily fouled 19 tube C-E model boiler test to investigate the potential for egg crate corrosion in aggressively fouled AVT chemistry are reported. Substantial support plate and egg crate corrosion was produced in this test. Carbon steel drilled support plates exhibited extensive denting which resulted in flow hole ligament cracking. Corrosion of the carbon steel egg crate, through-wall at areas of tube contact, resulted in denting of the Alloy 600 heat transfer tubes. Corrosion performance of the 409 stainless steel egg crate was improved compared to the carbon steel egg crate although localized through-wall corrosion was noted. The results from the above test and previously reported tests were compared based on the following simplifying assumptions: maximum dent size and/or corrosion penetrations utilized, average bulk water chloride concentrations, pilling bedworth ratios, pot and model boilers data are equivalent, heat flux not significantly ...
The authors report how the Midland cogeneration venture (MCV) is repowering the incomplete Midland nuclear plant to operate as a gas-fired combined cycle cogeneration facility. They discuss how their company is responsible for performing engineering, procurement, licensing, construction, start-up, training, and operational assistance for this facility. As shown, twelve gas turbine generator sets supply heat to twelve heat recovery steam generators (HRSGs), which are headered together on the steam side to provide energy to either of two existing steam turbine generators. This combination of equipment enables approximately 1,380 MWe of electrical generation capability, while supplying an average steam flow of 629,000 lbs/hr to an adjacent Dow Chemical Company pant. The MCV facility will also provide 60 MW of electric power to Dow. The authors report how the Midland ccogeneration venture (MCV) is repowering the incomplete Midland nuclear plant to ...
In this report, the descriptions of the DIVA test facility and those test matrixes are presented. The test sections simulate the downcomer annulus of DVI system with various scalling methodologies. The UPTF one has 1/7.5 scale and the APR-1400 test sections are reduced in 1/7 scale and 1/5 scale respectively. Also, the instrumentations, measuring methods are described. The major measuring parameters are ECC injection rate, air injection rate, bypass fraction, system pressure and so on. And finally, the operation procedure and experimental steps are introduced. From the DIVA tests, the multi-dimensional behaviors of two-phase flow in the downcomer during the reflood phase can be investigated using a transparent test facility. Also comparing the experimental data which are performed in various scale downcomer, it is expected that some criteria of scalling methodology proper to the DVI system can be derived. 10 refs., 19 figs., 10 tabs. (Author)
Thermal-hydraulics analysis can be used to determine location and magnitude of leaks inside a pressurized water reactor (PWR) containment, as required by plant technical specifications. The major advantage of this detection method is that it minimizes radiation exposure of maintenance personnel because most of the leak detection process is performed from the control room outside the containment. In addition, such a program allows for the elimination of pipe whip restraints and jet impingement shields, eliminating costs for maintenance of these supports and shields in older plants and lowering construction costs for new plants. Previously, only simple single-node containment models were used for determining leakage magnitude. This paper presents a more sophisticated multinode approach for determining the magnitude and location. The resulting sensitivities to leak can be programmed into the plant's computer system. In this way, the plant's computer ...
As an engineered barrier system in the geological disposal of high-level waste, multibarrier system is considered. Multibarrier system consists of the vitrified waste, the overpack and the buffer. Bentonite is one of the potential material as the buffer because of its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. As the construction technology of the buffer, the block installation method and in-situ compaction method, etc, are being investigated. The block installation method is to emplace the buffer blocks manufactured in advance at the ground facility, and construction processes of the block installation method at the underground will be simplified compared with the in-situ compaction method. However, the block joints of buffer might be a mechanical weak portion or might ...
A flow pattern or flow regime is the characteristics spatial distribution of the phases of fluid in a duct. Since heat transfer and pressure drop are dependent on the characteristic distribution of the phases, it is necessary to describe flow patterns in an appropriate manner so that a hydrodynamic or heat transfer theory applicable to that pattern can be chosen. The objective of the present analysis is to create a flow regime map based on physical modeling of vapor/liquid interaction phenomena in a microgravity environment. In the present work, four basic flow patterns are defined: dispersed flow, stratified flow, slug flow, and annular flow. Fluid properties, liquid and vapor flow rates, and pipe size were chosen as the principal parameters. It is assumed that a transition from ...
This report forms part of an independent review of the specifications, execution and results of Task 6 of the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes, which is seeking to provide a bridge between site characterization (SC) and performance assessment (PA) approaches to solute transport in fractured rock. The present report is concerned solely with Task 6C, which relates to the construction and parametrisation of a block-scale hydrostructural model of the TRUE Block Scale region of the Aespoe Hard Rock laboratory. The task objectives, specifications and outcome are summarised and reviewed. Also, consideration is given to how the hydrostructural model might affect the outcomes of Task 6D and 6E. The main conclusions of this review are summarised below: The Task 6C hydrostructural model is a more comprehensive approach to quantitatively describing a volume of fractured rock than has been achieved hitherto. The ...
Previous flow regime studies have been for horizontal, vertical, and inclined pipe flow. As such, only a few studies have been performed on bundle geometries. The present paper examines the flow regimes for a vertical hexagonal flow channel with and without a finned fuel bundle. This type of a 36 finned rod hexagonal fuel bundle in parallel hexagonal flow channels is used in a MAPLE (Multi- purpose Applied Physics Lattice Experimental) type nuclear reactor. An experiment apparatus was designed consisting of the flow channel, inlet plenum and an air-water separator. The inlet plenum is used to provide a uniform mixture of air and water before entering the hexagonal flow channel. A turbine flow meter is used to determine the water flow rate. The turbine flow meter is calibrated for ...
Vacuum insulation panels (VIP) offer excellent thermal resistance properties that can enhance the energy efficiency of insulating systems, save space and contribute to energy consumption reductions. However, VIPs are not used much in Canada, and new commitments to carbon dioxide reductions has created the need to study the prospect of using VIPs in various components of a building envelope. For that reason, assessment methods for the applicability and sustainability of VIPs for use in building envelope construction were developed. There are practical aspects regarding the long-term performance and application of VIPs in building construction. Air molecules and water molecules can permeate through the foil and seams of the VIPs, causing a reduction in thermal resistance. This paper addresses some of the test methods that may accelerate long term changes in thermal resistance. Results were presented from tests using elevated pressure, relative ...
Fisheries co-managers of U.S. v Oregon supported and directed the construction and operation of acclimation and release facilities for Snake River fall Chinook from Lyons Ferry Hatchery at three sites above Lower Granite Dam. In 1996, Congress instructed the U.S. Army Corps of Engineers (USCOE) to construct, under the Lower Snake River Compensation Plan (LSRCP), final rearing and acclimation facilities for fall Chinook in the Snake River basin to complement their activities and efforts in compensating for fish lost due to construction of the lower Snake River dams. The Nez Perce Tribe (NPT) played a key role in securing funding and selecting acclimation sites, then assumed responsibility for operation and maintenance of the facilities. In 1997, Bonneville Power Administrative (BPA) was directed to fund operations and maintenance (O&M) for the facilities. Two acclimation facilities, Captain John Rapids and Pittsburg ...
Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.
By applying the mass, momentum, and angular momentum conservation laws and the maximum flow rate principle to swirling, effectively inviscid, incompressible flows in a circular tube with a sudden expansion and the direct-flow and reversed-flow Borda mouthpieces the dependence of the flow rate coefficient and mechanical energy losses on the radius ratio and nondimensional circulation is obtained. Several calculating approaches with potential and helical motion are introduced and investigated. In the case of helical motion, as the swirl decreases the axial core of the flow is found to close with a sudden change of the flow parameters.
... tests, one often encounters, for instance, separated flows with large ... It is suspected that the flow-quality criteria given in AGARD Report No. ...
... Separation," AGARD,Rept 272, April 1960, ... Leading Edge Effect on Supersonic Boundary Layer Flow." ... of Gas Injection in Separated Flows." TCEA, ...
A method for calculating flow through an airfoil cascade drawn on a surface of revolution is discussed. The three-dimensional flow was assumed to be represented by part-channels of varying width. The basic equations are the equation of continuity and the ...
... AGARD AR-319, Volume 2. Knight, D., Zhou ... a Turbulent Boundary Layer in a Supersonic Flow. ... of Development of Separated Flows in Compression ...
... In: Separated Flows, AGARD CP No. ... on thin wings in two-dimensional incompressible flow. ... fields in the region of separating and reattaching flows. ...
... been demonstrated in steady compressible flows. ... steady Compressible Flow on an Oscillating Airfoil ... of Oscillating Airfoils", AGARD-CP-552, Aug. ...
... including those with rear separation, ... flows ibout airfoils." AIAA Paper 'Jo 97-0419, 1987). ... "Effects of streamline curvature on turbulent flow." AGARD ...
Analyses of process system properties were continued for important chemical materials involved in the several processes under consideration for semiconductor and solar cell grade silicon production. Major activities were devoted to physical, thermodynamic and transport property data for silicon. Property data are reported for vapor pressure heat of vaporization, heat of sublimation, liquid heat capacity and solid heat capacity as a function of temperature to permit rapid usage in engineering. Chemical engineering analysis of the HSC process (Hemlock Semiconductor Corporation) for production of silicon was initiated. The process is based on hydrogen reduction of dichlorosilane (DCS) to produce the polysilicon. The chemical vapor deposition reaction for DCS is faster in rate than the conventional process route which utilizes trichlorosilane (TCS) as the silicon raw material. Status and progress are reported for primary activities of base case conditions (30%), reaction chemistry (25%) ...
During third quarter 1994, samples from AMB groundwater monitoring wells at the Metallurgical Laboratory Hazardous Waste Management Facility (Met Lab HWMF) were analyzed for selected heavy metals, indicator parameters, radionuclides, volatile organic compounds, and other constituents. Eight parameters exceeded standards during the quarter. As in previous quarters, tetrachloroethylene and trichloroethylene exceeded final Primary Drinking Water Standards (PDWS). Bis(2-ethylhexyl) phthalate exceeded final PDWS in one well. Aluminum, iron, manganese, tin, and total organic halogens exceeded the Savannah River Site (SRS) Flag 2 criteria. Groundwater flow direction and rate in the M-Area Aquifer Zone were similar to previous quarters. Conditions affecting determination of groundwater flow directions and rates in the Upper Lost Lake Aquifer Zone, Lower Lost Lake Aquifer Zone, and the Middle Sand Aquifer Zone of the Crouch Branch Confining Unit were ...
A study was made for the purpose of electrification of unelectrified zones of the mountainous areas in developing countries using extremely small hydroelectric power facilities. The target for this project is a development of a micro hydroelectric power system with a size of about 5kW, which is estimated regarding that 1 village has 80 houses and each house needs electricity of 60W. In the study, the low-head system using a weir of irrigation channels in Subang pref. of West Java state was selected by the evaluation of access, stability of flow rate, natural conditions, etc. The hydroelectric power plant is of a flow-in method in which water is taken from the left bank and is injected/discharged to the downstream of the left bank. As the hybrid complementary power source, hybrid battery with a two-hour charging time at peak and a capacity of 3.5kWh was considered. When estimating the construction cost of the hybrid micro ...
OBJECTIVE: To use Medicaid claims data to construct patient origin-based market areas for dental services and compare constructed market areas with those based on the practice county. DATA SOURCES:...Full Text Available
Describes the light construction curriculum offered at Carteret Technical College, NC, in terms of course offerings, program finances, problems, and the establishment of tax-exempt endowment corporation through which the program was funded. Concludes with suggestions for organizing a construction program. (AYC)
Nuclear power plants of 20 units of in Korea are generating about 700 MTU of spent fuels annually. The inventory of spent fuels in Korea were estimated about 10,087.07 MTU at end of 2008, and the storage space of spent fuels won't be available any more at 2016 due to the saturation of the spent fuel pools in the plants. In addition, in order to reduce carbon emission and correspond to the enormous electricity demand in Korea, 8 units of nuclear power plants are under construction and several more plants are under planning. The 100,000 MTU of spent fuel inventory are expected by the year of 2095 in Korea. Therefore, short term and long term of spent fuel management plans are under discussion and implementation in Korea. As a short term of spent fuel management strategy for the target year of 2016, central or local spent fuel dry interim storage options are mostly under discussion. As a long term of management plan, fast reactor and advanced fuel cycle R and D plan ...
Canada's offshore Atlantic petroleum industry is celebrating its tenth anniversary in 2001. This article chronicles the development of the industry discussing the many challenges and setbacks and the eventual triumphs that accompanied the industry's development over the years. Highlights discussed include shipping first oil from the Cohasset Field in July 1992; the financial crisis caused by the withdrawal of Gulf Oil from the Hibernia consortium in the same year; new funding and the beginning of the gravity-based structure construction at Bulls Arm in 1993; striking oil in the Hibernia Field in 1994; the start of exploration and development of the Terra Nova field by Petro-Canada in the same year, based on the floating production, storage and offloading (FPSO) system, which heralded a new era of offshore development in eastern Canada. Approval by the Nova Scotia government of the third and final phase of the Sable Offshore Energy Project followed ...
This report presents the methodology and the results from the modelling of an open repository for spent nuclear fuel in Laxemar. Specifically, the present work analyses the hydrological effects of the planned repository during the construction and operational phases when it is open, i.e. air-filled, and hence may cause a disturbance of the hydrological conditions in the surroundings. The numerical modelling is based on the SDM-Site Laxemar MIKE SHE model. The modelling was divided into three steps. The first step was to update the SDM-Site Laxemar model with a new hydrogeological bedrock model. The other main updates were an increase of the depth of the MIKE SHE model domain, enhanced vertical computational resolution and that the drainage of the Aespoe Hard Rock Laboratory was included in the model. The resulting model was used to simulate undisturbed natural conditions. The next step was to describe the open repository conditions, using Laxemar layout D2, by ...
... Agard Report 272,1960 ... and reattached subsonic turbulent flows obtained downstream ... of flow separations due to deflected control surfaces. ...
Visualizations by real-time neutron radiography are demonstrated of various flow patterns of nitrogen gas-water two-phase flow in a stainless-steel tube, water inverted annular flow in a stainless-steel tube, flashing flow in an aluminium nozzle and fluidized bed in aluminium tube and vessels. Photographs every 1/60 s are presented by an image processing method to show the dynamic behaviours of the various flow patterns. It is shown that this visualization method can be applied efficiently to multiphase flow researches and will be applicable to multiphase flows in industrial machines. (author).
Visualizations by real-time neutron radiography are demonstrated of various flow patterns of nitrogen gas-water two-phase flow in a stainless-steel tube, water inverted annular flow in a stainless-steel tube, flashing flow in an aluminium nozzle and fluidized bed in aluminium tube and vessels. Photographs every 1/60 s are presented by an image processing method to show the dynamic behaviours of the various flow patterns. It is shown that this visualization method can be applied efficiently to multiphase flow researches and will be applicable to multiphase flows in industrial machines. (author).
In this paper information about monograph construction is provided and some sample nomographs constructed by the author are included to encourage the use of these tools in operational health physics applications.
... revetment construction, water well drilling, mobile facility assets construction using ... five days, and establish site layout for the follow-on RH ... modules. ...
discharges. Proposed Stormwater ELG from Construction Sites - EPA has proposed effluent limitations guidelines (ELGs) and new source performance standards (NSPS) to control...
Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.
A Real-Time Neutron Radiography (RTNR) system is used to determine two-phase flow parameters for a horizontal co-current two-phase flow channel with a CANDU-type 37 rod bundle. Image processing techniques are applied to visualize the two-phase flow, and to determine flow regime, cross-sectional averaged void fraction, time averaged void fraction, and void distribution. The experimentally determined flow regime map disagrees with existing flow regime models developed for the CANDU-type rod bundles. A new flow regime is observed and designated Large Amplitude Stratified Wavy flow. The results show that the LASW flow regime may be due to a combination of undeveloped flow phenomena, boundary conditions, and circumferential cross flow occurring in the bundle. The ...
A real-time neutron radiography (RTNR) system is used to determine two-phase flow parameters for a horizontal co-current two-phase flow channel with a cylindrical 37 rod bundle. Image processing techniques are applied to visualize the two-phase flow, and to determine flow regime, cross-sectional averaged void fraction, time averaged void fraction, and void distribution. The experimentally determined flow regime map disagrees with existing flow regime models developed for the cylindrical rod bundles. A new flow regime is observed and designated large amplitude stratified wavy (LASW) flow. The results show that the LASW flow regime may be due to a combination of undeveloped flow phenomena, boundary conditions, and circumferential cross flow occuring in the ...
A Real-Time Neutron Radiography (RTNR) system is used to determine two-phase flow parameters for a horizontal co-current two-phase flow channel with a CANDU-type 37 rod bundle. Image processing techniques are applied to visualize the two-phase flow, and to determine flow regime, cross-sectional averaged void fraction, time averaged void fraction, and void distribution. The experimentally determined flow regime map disagrees with existing flow regime models developed for the CANDU-type rod bundles. A new flow regime is observed and designated Large Amplitude Stratified Wavy flow. The results show that the LASW flow regime may be due to a combination of undeveloped flow phenomena, boundary conditions, and circumferential cross flow occurring in the bundle. The ...
Between 25 and 30 percent of total known petroleum reserves are contained within oil-laden fractured reservoirs where the dominant flow path is through the fractures. Economic oil recoveries from fractured reservoirs depend on a better understanding of the flow in fractures and networks of fractures. However, the flow of heavy oil and water, and particularly the flow regime map for two-phase immiscible flow has received less attention in contrast with gas-liquid flow in fractures. This paper discussed the use of flow pattern observations in a Hele-Shaw cell to generate two-phase flow regime maps. The paper investigated the effect of fracture gap and fluid viscosities on flow regimes. A correlation based on different flow and fracture properties was developed to define ...
Applications, techniques, instrumentation, and interpretation of flow visualization are discussed. Methods of using flow visualization for the examination of combustion in furnaces, heat transfer with heat exchangers, and in fluid engines are explored, along with flow visualization in food processing, steel-casting, and process engineering. Further attention is given to pipe and channel flow, flow separation in laminar flow and around oscillating airfoils, wakes and vortices, supersonic flow and shock waves, and stratified flow and oceanography. The visualization of boundary layers is considered for various conditions, and applications for multiphase flow, rheology, and medical problems are detailed. Oil film, dry-surface coating, chemical, fluorescent, and minituft methods are presented, as well as ...
In the present study, a new measurement technique which uses a ultrasonic transmission signals in order to determine the vertical two phase flow pattern even under high pressure condition. The ultrasonic measurement system developed in the present study not only provides the measurement functions required for the determination of vertical two phase flow pattern but also makes the real time determination possible. The developed ultrasonic measurement system accurately determined the various vertical two phase flow patterns such as bubbly, slug, churn, annular flow etc. In addition to the determination of flow patterns, qualitative informations for each flow pattern can be obtained, which include void fraction in bubbly flow, length of slug bubble and liquid tail characteristics in slug flow, and stable or transient ...
A two-phase flow regime map is developed experimentally and theoretically for a vertical hexagonal flow channel with and without a 36-finned rod hexagonal bundle. This type of flow channel is of interest to MAPLE-type nuclear research reactors. The flow regime maps are determined by visual observations and observation of waveforms shown by a capacitance-type void fraction meter. The experimental results show that the inclusion of the finned hexagonal bundle shifts the flow regime transition boundaries toward higher water flow rates. Existing flow regime maps based on pipe flow require slight modifications when applied to the hexagonal flow channel with and without a MAPLE-type finned hexagonal bundle. The proposed theoretical model agrees well with experimental results.
A two-phase flow regime map is developed experimentally and theoretically for a vertical hexagonal flow channel with and without a 36-finned rod hexagonal bundle. This type of flow channel is of interest to MAPLE-type nuclear research reactors. The flow regime maps are determined by visual observations and observation of waveforms shown by a capacitance-type void fraction meter. The experimental results show that the inclusion of the finned hexagonal bundle shifts the flow regime transition boundaries toward higher water flow rates. Existing flow regime maps based on pipe flow require slight modifications when applied to the hexagonal flow channel with and without a MAPLE-type finned hexagonal bundle. The proposed theoretical model agrees well with experimental results.
Many pump reliability problems in the Nuclear Power Plants (NPPs) are being attributed to the operation of the pump at flow rates well below its best efficiency point(BEP). Generally, the manufacturer and the user try to avert such problems by specifying a minimum flow, below which the pump should not be operated. Pump minimum flow usually involves two considerations. The first consideration is normally termed the 'thermal minimum flow', which is that flow required to prevent the fluid inside the pump from reaching saturation conditions. The other consideration is often referred to as 'mechanical minimum flow', which is that flow required to prevent mechanical damage. However, the criteria for specifying such a minimum flow are not clearly understood by all parties concerned. Also various factor and information for ...
... harassment, incidental to construction and operation of an offshore liquefied natural gas (LNG) facility. Under the Marine Mammal Protection ... ...
The inner part of a fusion reactor will have to operate at very high neutron loads. In steady-state reactors the minimum fluence before the scheduled replacement of the reactor core should be at least l0-15 Mw.yr/m2. A more frequent replacement of the core is hardly compatible with economic constraints. A most recent summary of the discussions of these issues is presented in Ref. [l]. If and when times come to build a commercial fusion reactor, the availability of information on the behavior of materials and components at such fluences will become mandatory for making a final decision. This makes it necessary an early development and construction of a neutron source for fusion material and component testing. In this paper, we present information on one very attractive concept of such a source: a source based on a so called Gas Dynamic Trap. This neutron source was proposed in the mid 1980s (Ref. [2]; see also a survey [3] with discussion of ...
Different calculated models are presented for turbulent break-off flows and their classification, reflecting the sequence of historical development. The study was done based on equations of viscous liquid of the Navier-Stokes type with development of special phenomenological models of turbulence which take into consideration real properties of the break-off flows based on simpler models of flow presented in the work. In order to calculate two-dimensional turbulent flows, a method of viscous-nonviscous interaction is used. It employs numerical solutions for nonviscous flow and integrated methods of calculating the dissipative region. This method can be extended for calculating the transonic break-off flows, and also break-off in an incompressible fluid when there is cavitation.
The contribution examines whether the construction of high-voltage transmission lines without formal participation of local authorities is permissible. In this connection the question is also treated to what extent municipal co-determination in transmission line construction represents a precondition for the permissibility of compulsory purchase measures. The individual issues treated are: the formal legal situation and current practice in the construction of electricity pylons; individual legal protection in connection with compulsory purchase; the construction of pylons without a construction licence as an infringement of the municipal right to self-government of local authorities; and the effects on the execution of compulsory purchase procedures of the illegality under Building Law of pylons constructed without approval. (RST).
Purpose - This paper seeks to analyse the hypothesis that sustainability is destined to become the operating paradigm for construction education in the UK. Design/methodology/approach - An international literature review is used to assess the relationship between sustainability and the built environment. The viewpoints of the construction-related professions are examined by analysing the accreditation policies of key professional bodies and through a survey of public sector-based UK building professionals. International and national policy initiatives on educating for sustainability are reviewed and a survey of UK universities delivering construction degrees is used to explore the environmental content of construction courses. A brief case study describes recent efforts to systematically e...
This paper describes the study of particles' dispersion in an isotropic turbulent flow. The particle's motion and the turbulent flow characteristics are calculated independently. While the particles' displacement is computed by the author's code, the flow is simulated with a commercial code : PowerFLOW. The particles and the flow are coupled through the relative velocity component of the aerodynamic force. When the simulated flow is turbulent, a turbulence regeneration model is used in order to get the flow instantaneous velocity. Validation of the method is done by comparing the particles' dispersion obtained with experimental results from literature and with the results calculated by FLUENT. Good accordance is found between numerical studies and experimental results. However, comparison between results of PowerFLOW ...
In order to understand the detail transient two-phase flow structure, more advanced two-phase flow instrumentation is required. One advanced technique for flow visualization is real-time neutron radiography. Reconstruction method of visualized radiographic image of liquid metal two-phase flow generated by the real-time neutron radiography system is proposed in this paper. Image processing techniques for noise reduction and image enhancement are discussed in detail. (author).
In order to understand the detail transient two-phase flow structure, more advanced two-phase flow instrumentation is required. One advanced technique for flow visualization is real-time neutron radiography. Reconstruction method of visualized radiographic image of liquid metal two-phase flow generated by the real-time neutron radiography system is proposed in this paper. Image processing techniques for noise reduction and image enhancement are discussed in detail. (author).
This paper presents a numerical investigation of laminar flows and heat transfer in a horizontal rectangular channel whose top and bottom plates have been punched out in the form of a delta wing. The flow structure with respect to the generation, transport, and stability of vortices in laminar horizontal channel flows with combined forced and free convection are reported. To include free convection, Boussinesq approximation of the buoyancy is used and the flow medium is treated as incompressible.
Two-phase flow in horizontal parallel channels has been experimentally investigated under fuel cell related operating conditions. Pronounced hysteresis is observed in the pressure drop versus flow characteristic curve when starting from either flooded or dry conditions. When gas is introduced into channels initially filled with water (flooded initial condition), both gas and liquid tend to flow predominantly in one channel at low gas or liquid flow velocities. As the gas flow velocity increases, even distribution of gas and liquid flow in both channels is observed, accompanied with a sudden decrease in the pressure drop. On the other hand, even gas and liquid flow distribution between both channels is found at comparatively lower gas flow velocities when starting with dry-gas flow conditions with ...
Ontario's electricity industry restructuring program is reviewed, with a view to identify the reasons behind the failure of deregulation which was expected to create competition, to stabilize, or even reduce, prices to consumers, and attract serious private sector investment for the construction of new generating capacity. The report painstakingly reviews the series of events which resulted in a steep rise in electricity rates during the summer of 2002, immediately after deregulation came into effect, which led to freezing retail electricity rates and related charges by the then Conservative provincial government, and the reversal of that decision by the newly-elected Liberal government in the fall of 2003, and plans to bring back retail hydro rates that reflect the cost of production. The authors provide a discussion of policy options and a series of recommendations that are expected to create incentives to reduce and shift demand, encourage the use of ...
A new air injection process called toe-to-heel air injection (THAI) has been developed to achieve very stable combustion performance in heavy oil wells by controlling gas override. In the THAI process, injected air migrates preferentially to the combustion front into a horizontal producer well by the oxygen diffusional gradient created under steady state conditions. This is possible because of the balance between the stoichiometric oxygen flux needed to burn the fuel (coke) laid down ahead of the combustion front and the removal of downstream combustion gases and mobilised fluids. This study involved a numerical simulation of the THAI process to increase the understanding of the processes involving fluid flow, heat transfer and chemical reactions taking place during in situ combustion. Two tests were conducted involving one dry and one wet combustion using heavy Wolf Lake Oil. The objective was to determine if the behaviour of the oil could be predicted. A ...
Tidally dominated sections from the Middle Jurassic Beryl Formation of the Beryl Field, Viking Graben (UKCS) were deposited during rapid changes in relative sea level. High density well coverage in this key producing interval has allowed the construction of an integrated high resolution sequence stratigraphic scheme based on sedimentological, ichnofaunal, wireline, biostratigraphic and engineering data. From this database a number of high resolution sequences in the Bajocian-Bathonian Beryl Formation have been identified composed of interbedded sandstones, siltstones and mudstones. These sediments formed tidally-influenced deltas and estuaries deposited in actively subsiding half-grabens during regionally extensive base-level changes. For reservoir management purposes, the formation has been split into 5 units. The thickest interval, Unit 3, is considered here. In the northern part of the Beryl Field, Unit 3 is bounded above and below by regionally extensive, ...
A design for passive cooling of large containment structures has progressed sufficiently to move forward into the detailed design stage necessary for plant construction. For such application, a safety analysis report has already been submitted to the US Nuclear Regulatory Commission. The design considers an annulus between the inner steel containment vessel and outer, thick-walled concrete shield building with chimney-like natural convection cooling driven only by a density gradient relative to the atmosphere. Air within the annulus is heated as internal containment temperature rises and heat is transferred through the steel containment shell. The resulting air density gradient between the annulus and the environment causes the heated air to rise, producing a natural convection flow through inlets in the shield building, past the steel shell, and out an exit chimney. Several options for enhancing passive heat removal of large containment ...
This annual report describes the progress during the fifth year of the project which is targeted towards improving the reservoir performance of mature oil fields located in fluvially dominated deltaic geological environments. The project involves using an integrated approach to characterize the reservoir followed by proposing an appropriate reservoir management strategy to improve the field performance. In the first stage of the project, the type data the authors integrated include cross borehole seismic surveys, geological interpretation based on the logs and the cores, and the engineering information. In contrast, during the second stage of the project, they intend to use only conventional data to construct the reservoir description. This report covers the results of the implementation from the first stage of the project. It also discusses the work accomplished so far for the second stage of the project. The production from the Self Unit (location of Stage I) has ...
This annual report describes the progress during the fourth year of the project on {open_quotes}Integrated Approach Towards the Application of Horizontal Wells to Improve Waterflooding Performance{close_quotes}. The project involves using an integrated approach to characterize the reservoir followed by proposing an appropriate reservoir management strategy to improve the field performance. In the first stage of the project, the type of data we integrated include cross borehole seismic surveys, geological interpretation based on the logs and the cores, and the engineering information. In contrast, during the second stage of the project, we intend to use only conventional data to construct the reservoir description. This report covers the results of the implementation from the first stage of the project. It also discusses the work accomplished so far for the second stage of the project. The production from the Self Unit (location of Stage 1) has sustained an increase ...
Due to its important hydroelectric power generation facilities (about 525 plants with a total power of 13,314 MW producing about 35.3 TWh annually) Switzerland plays an important role in the interconnected European power system. Large artificial storage lakes in the Swiss Alps can generate peak power during hours of highest demand: 9700 MW are available from accumulated energy and the total power of pumped-storage facilities amounts to 1700 MW. The latter allow refilling the reservoirs at periods of low power demand and generating power at periods of peak demand. In the case of favorable conditions, the yearly average power production could be increased by 6% and the production during the winter period (October to March) by 20% by the year 2020. However, looking forward to the year 2050, the annual production is expected to decrease by 3% despite a possible extension of hydropower. This decrease is due to the enforcement of the minimum residual water flow rates ...
Investigation and flow testing of the enlarged Phase I heat-extraction system at Fenton Hill continued throughout FY80. Temperature drawdown observed at that time indicated an effective fracture of approximately 40,000 to 60,000 m/sup 2/. In May 1980, hot dry rock (HDR) technology was used to produce electricity in an interface demonstration experiment at Fenton Hill. A 60-kVA binary-cycle electrical generator was installed in the Phase I surface system and heat from about 3 kg/s of geothermal fluid at 132/sup 0/C was used to boil Freon R-114, whose vapor drove a turboalternator. A Phase II system was designed and is now being constructed at Fenton Hill that should approach commercial requirements. Borehole EE-2, the injection well, was completed on May 12, 1980. It was drilled to a vertical depth of about 4500 m, where the rock temperature is approximately 320/sup 0/C. The production well, EE-3 had been drilled to a depth of 3044 m and ...
This thesis surveys the concepts of exergy and extends the exergy method of analysis from the standpoint of its applications to the power plant systems. After a brief historical review of exergy concepts, the general exergy equation is derived from the combined equation of First and Second Law, and it is shown that any special case of exergy equation is a simplified form of the general exergy equation. The mathematical method for the exergy analysis of a steady-state, steady-flow system, analogous to that of the First Law, is given. The exergy losses in a power plant are discussed. Then in order to examine these losses, the Second Law performance of major processes of combustion, compression, heat transfer, mixing and throttling have been analyzed analytically, and the exergy efficiencies are defined that accurately assess the thermodynamic performance of the corresponding processes. The methods for computation of exergy loss and exergy efficiency are given and ...
In order to develop new corrosion resistant superheater tubes capable of functioning efficiency under temperature and pressure conditions of 500 C and 100 ata used in high efficient waste-to-energy (WTE) plants, field corrosion tests were conducted on eight single tube materials and two welded overlay materials at metal temperatures of 450 C and 550 C for 700 and 3,000 hours, respectively, in three typical japanese waste incineration plants. The test results indicate that austenitic alloys containing higher concentrations of [Cr + Ni + Mo] show excellent corrosion resistant properties and new alloys of JHN24 and HR30M have good corrosion resistance. The different corrosion rate found for each of the three plants could be explained by differences in the severity of corrosion factors, such as, gas temperature, concentration of molten salts due to Cl content of deposits, and heavy metal [ZnO + PbO] content etc. It was also confirmed that the corrosion rate of materials positioned in the ...
Due to the high investment and operation costs incurred by dryers up to 50% of the proceeds from the cultivation of medicinal plants have to be spent on drying. This study was conducted in order to determine whether these costs can be lowered when solar energy is used. As little is known about the drying behaviour of medicinal plants even today one selected sage and camomile in order to study the influence of temperature, relative humidity, and drying air velocity on drying time and drug quality. Laboratory results were used as a basis for developing a solar hothouse dryer for medicinal plants which uses the whole roof surface as solar collectors with a batch dryer set up within the hothouse. In contrast to dryers of this type used up to now a foil green house with a gable roof was used. Installation of a central heating system helps to avoid bottlenecks, allows drying at night and increases plant flow by a factor of 3. The cost of heating oil, however, adds to the ...
In the heat exchangers of power plants, scale deposition may occur, especially at the leading edge of contraction. The growth of scale can lead to an increase in pressure and cause oscillation of the water level. In our previous study, the dependence of flow on contraction geometry was analyzed numerically and empirically. It was shown that the contraction ratio of hydraulic diameter of the flow path contributed greatly to the difference in pressure drop and turbulent kinetic energy at the leading edge of the flow path. In this study, the effect of contraction geometry and flow rate on scale adhesion was studied in AVT chemistry at 270degC using a high-velocity scale-adhesion test loop. The differential pressure and the amount of scale deposited due to scale adhesion at the leading edge of the flow path increased more in a quatrefoil-type flow path than in ...
The following subjects are dealt with: physics of indoor air flow, flow in individual rooms, exchange of air and pollution between individual building zones and with the outside world, thermal coupling with the building shell, thermal comfort and air quality, evaluation of the ventilation. figs., tabs., refs.
REAL ENGINE FLOW SIMULATION. 4 C D - 8 5 - 1 6 9 6 4. FIGURE 2. - COMPLEX FLOW PHENOMENA IN A TURBINE PASSAGE,. SEE TABLE I FOR DESCRIPTION OF NUMBERED FLOW ...
The multidimensional countercurrent two-phase flow regimes that occur in a pressurized-water reactor (PWR) vessel downcomer during the refill phase of a large-break loss-of-coolant accident are studied using a transparent 1/10 scale model of a PWR vessel. The various flow regimes and their distribution in the downcomer have been identified and mapped for a range of air-water flooding experiments. The two-phase flow patterns that are identified in the downcomer included various types of film flows, droplet flows, countercurrent churn flows and cocurrent flows depending on the flooding condition. Through observation of the two-phase flow dynamics it was deduced that the physical mechanisms associated with the flooding processes could be separated into a liquid entrainment process and a film flow ...
The multidimensional countercurrent two-phase flow regimes that occur in a pressurized-water reactor (PWR) vessel downcomer during the refill phase of a large-break loss-of-coolant accident are studied using a transparent 1/10 scale model of a PWR vessel. The various flow regimes and their distribution in the downcomer have been identified and mapped for a range of air-water flooding experiments. The two-phase flow patterns that are identified in the downcomer included various types of film flows, droplet flows, countercurrent churn flows and cocurrent flows depending on the flooding condition. Through observation of the two-phase flow dynamics it was deduced that the physical mechanisms associated with the flooding processes could be separated into a liquid entrainment process and a film flow ...
Traditional two-phase flow-regime criteria based on the gas and liquid superficial velocities may not be suitable to the analyses of rapid transient or entrance flows by the two-fluid model. Under these conditions, it is postulated that direct geometrical parameters such as the void fraction are conceptually simpler and therefore more reliable parameters to be used in flow-regime criteria than the traditional parameters. From this point of view, new flow-regime criteria for upward gas-liquid flow in vertical tubes have been developed considering the mechanisms of flow-regime transitions. These new criteria can be compared to existing criteria and experimental data under steady-state and fully developed flow conditions by using relative velocity correlations. The criteria showed reasonable agreements with the existing data for atmospheric ...
Traditional two-phase flow-regime criteria based on the gas and liquid superficial velocities may not be suitable to the analyses of rapid transient or entrance flows by the two-fluid model. Under these conditions, it is postulated that direct geometrical parameters such as the void fraction are conceptually simpler and therefore more reliable parameters to be used in flow-regime criteria than the traditional parameters. From this point of view, new flow-regime criteria for upward gas-liquid flow in vertical tubes have been developed considering the mechanisms of flow-regime transitions. These new criteria can be compared to existing criteria and experimental data under steady-state and fully developed flow conditions by using relative velocity correlations. The criteria showed reasonable agreements with the existing data for atmospheric ...
Various measurement tools that are used in chaos theory were applied to analyze two-phase pressure signals with the objective of identifying and interpreting flow pattern transitions for two-phase flows in a small, horizontal rectangular channel. These me...
shown of inviscid shocked flow with and without separation and shock-free flow with separation. An Euler solu- tion with ... THE existence of flow separation and recirculation is ..... Solutions for AGARD Test Cases," NASA TM, to be published. ...
This paper provides information on heat transfer enhancement due to jet mixing inside a cylindrical enclosure. The work addresses conservative heat transfer assumptions regarding mixing and condensation that have typically been incorporated into passive containment design analyses. The current research presents an interesting possibility for increasing decay heat removal of passive containment systems under combined natural and forced convection. Eliminating these conservative assumptions could provide the basis for a change of containment design and reduce the construction cost. It is found that the ratio of forced- and free convection Nusselt numbers can be predicted as a function of the Archimedes number and a correlated factor accounting for jet orientation and enclosure geometry. To use the small-scale tests for large containment design, scale-up methods and criteria are important for matching the key governing parameters and fluid properties. In the present ...
The need for a Combustion and Melting Research Facility focused on the solution of glass manufacturing problems common to all segments of the glass industry was given high priority in the earliest version of the Glass Industry Technology Roadmap (Eisenhauer et al., 1997). Visteon Glass Systems and, later, PPG Industries proposed to meet this requirement, in partnership with the DOE/OIT Glass Program and Sandia National Laboratories, by designing and building a research furnace equipped with state-of-the-art diagnostics in the DOE Combustion Research Facility located at the Sandia site in Livermore, CA. Input on the configuration and objectives of the facility was sought from the entire industry by a variety of routes: (1) through a survey distributed to industry leaders by GMIC, (2) by conducting an open workshop following the OIT Glass Industry Project Review in September 1999, (3) from discussions with numerous glass engineers, scientists, and executives, and (4) during visits to ...
The details of pulsating stochastic flows accompanying the interaction of a microwave filament (regarded as a heated rarefied channel) and an aerodynamic body in supersonic flow are examined numerically using the Euler equations. Symmetrical and asymmetrical filament locations relative to the aerodynamic body are considered. The flowfields are characterized by large scale pulsations and small scale stochastic fluctuations. The mechanisms of the formation of these flow structures are discussed. Two qualitatively different kinds of flowfields are observed depending on the magnitude of the filament radius, with domination of the pulsations of flow parameters or stochastic phenomena. Flow instabilities inherent to the problems under interest are described. The problems are considered in both p...
It is both experimentally and theoretically demonstrated that ion flow velocity at an arbitrary angle with respect to the magnetic field can be measured with a directional Langmuir probe. Based on the symmetry argument, we show that the effect of magnetic field on directional probe current is exactly canceled in determining the ion flow velocity, and obtain the generalized relation between flow velocity and directional probe currents valid for any flowing direction. The absolute value of the flow velocity is determined by an in situ calibration method of the probe. The applicability limit of the present method to a strongly ion-magnetized plasma is experimentally examined. (author)
In FY 1984 three specific tasks which are all related to not-well-understood two-phase phenomena of importance to LWR accidents have been identified under the program. These three tasks are: (1) inverted annular flow experiments and modeling; (2) hot leg U-bend two-phase flow simulation study; and (3) development and evaluation of two-phase flow scaling criteria. Some of the important results obtained under Tasks (1) and (2) are reported in this paper.
This paper deals with a mixed convection water flow in a horizontal rectangular duct, uniformly heated from one lateral vertical wall and thermally insulated elsewhere. The supplied heat flux induces a secondary flow, which structure is constituted of one longitudinal roll in the considered aspect ratio (??=?1.9), embedded into a return flow of possibly large stream wise extension (up to twenty channel heights). Such situation induces helicoidal trajectories for the fluid flow particles, which contributes to a heat transfer enhancement compared to purely forced convection flow.
This paper deals with a mixed convection water flow in a horizontal rectangular duct, uniformly heated from one lateral vertical wall and thermally insulated elsewhere. The supplied heat flux induces a secondary flow, which structure is constituted of one longitudinal roll in the considered aspect ratio (? = 1.9), embedded into a return flow of possibly large stream wise extension (up to twenty channel heights). Such situation induces helicoidal trajectories for the fluid flow particles, which contributes to a heat transfer enhancement compared to purely forced convection flow.
Two constructions due to Dr\\'apal produce a group by modifying exactly one quarter of the Cayley table of another group. We present these constructions in a compact way, and generalize them to Moufang loops, using loop extensions. Both constructions preserve associators, the associator subloop, and the nucleus. We conjecture that two Moufang 2-loops of finite order $n$ with equivalent associator can be connected by a series of constructions similar to ours, and offer empirical evidence that this is so for $n=16$, 24, 32; the only interesting cases with $n\\le 32$. We further investigate the way the constructions affect code loops and loops of type $M(G, 2)$. The paper closes with several conjectures and research questions concerning the distance of Moufang loops, classification of small Moufang loops, and generalizations of the two constructions.
MR images of steady and pulsatile disturbed flow, obtained with use of flow-compensated spin-echo (SE) and cine pulse sequences, revealed excellent flow visualization in three dimensions. Phantoms, built from molds of actual blood vessels, reproduced laminar, disturbed, or turbulent flow. Video recording (VR), performed under conditions equivalent to those of the MR experiments, showed separation zones identical to those seen on SE images. Pulsatile flow studies showed complex patterns of vortical flow on cine images and VR. Varying pulse sequence details changed contrast but not flow patterns. The validation of MR observations by VR has implications for clinical cine imaging and low abnormal signals observed on MR angiograms.
A visual study of film boiling is carried out to determine the flow regime transition in the post-CHF region. An idealized inverted annular flow is obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas velocities are 0.05-0.5 and 0.03-8.2 m s/sup -1/. Nitrogen and helium are used in the study. For the present configuration, there are four flow regimes; namely, the smooth inverted annular flow-section, the rough wavy, agitated and dispersed flow regimes.
A visual study of film boiling is carried out to determine the flow regime transition in the post-CHF region. An idealized inverted annular flow is obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas velocities are 0.05-0.5 and 0.03-8.2 m s"-"1. Nitrogen and helium are used in the study. For the present configuration, there are four flow regimes; namely, the smooth inverted annular flow-section, the rough wavy, agitated and dispersed flow regimes. (author).
In this paper, the widely used models of Taitel-Dukler and Weisman et al. are extrapolated to microgravity levels to compare predicted flow pattern boundaries for horizontal and vertical flows. Efforts have been made to analyze how the two-phase flow models available in the literature predict flow regime transitions in microgravity. The models of Taitel-Dukler and Weisman et al. have been found to be more suitable for extrapolation to a wide range of system parameters than the other two-phase flow regime maps available in the literature. The original criteria for all cases are used to predict the transition lines, except for the transition to dispersed flow regime in case of the Weisman model for horizontal flow. The constant 0.97 on the righthand side of this correlation should be two times that value, i.e., 1.94, in order to match this ...
This paper describes a series of tests investigating two-phase flow regimes in a transparent model of a PWR hot leg. Test conditions were selected to cover a wide range of gas and liquid superficial velocities (.01 m/s 2 m/s) were also performed for comparison with semi-analytical predictions. Results include average void fractions, flow rates, and visual characterizations of the two-phase flow phenomena. Results show generally good agreement with Taitel and Duckler flow regime map and Zuber-Findlay correlation for average void fraction in vertical pipes. Results also indicate that flow regimes and collapsed liquid level (void fraction) are more strongly dependent on air flow rate (air superficial velocity) than water flow rate (water superficial velocity).
... 14(a)), a short laminar separation bubble is evident on the ... Natural Laminar Flow and Laminar Flow Control, RW Barnwell and MY ... AGARD CP No. ...
Absolute measurements of cerebral blood flow (CBF) are an important endpoint in studies of cerebral pathophysiology. Currently no accepted method exists for in vivo longitudinal...Full Text Available
AIM: To investigate the effects of gallbladder stones on motor functions of the gallbladder and the dynamics of bile flow in asymptomatic gallstone disease.METHODS: Quantitative hepatobiliary...Full Text Available
Jan 31, 2002 ... Sequential Flow of EDA Functionality for Flow with Separation ...... for Automated Air Traffic Management," AGARD Lecture Series No. ...
flow over the suction surface of a modern low- ..... the flow because of its proximity to the separation point ..... Pressure Turbines, AGARD Lecture Series 167, ...
... of the cycle shows that the separation area ea. ... with suitable flow solvers based on the Reynolds ... AGARD 75th Fluid Dynamics Panel Meeting and ...
A Real-Time Neutron Radiography (RTNR) system is developed to determine two-phase flow parameters for a vertical co-current two-phase flow channel with a hexagonal finned bundle. Image processing techniques are applied to visualize the two-phase flow, and procedures for measuring flow regime, cross-sectional averaged void fraction, time averaged void fraction, and void distribution for this complex geometry are discussed. The results show that the experimental flow regime map agrees well with an existing flow regime model for a hexagonal fined bundle. The hexagonal finned bundle is observed to significantly affect the void fraction, void migration, and void fluctuation along the axial flow channel.
Flow cytometry (FCM) is widely used in health research and in treatment for a variety of tasks, such as in the diagnosis and monitoring of leukemia and lymphoma patients, providing the counts of helper-T...Full Text Available
Valve Flow Characteristics. 3-68. 3-40. Valve Operating Current Vs. Temperature ...... VALVE FLOW CHARACTERISTICS. Acceptance Test 4/29/74. SINs 002 & 004 ...
A visual study of film boiling using photographic and high speed motion-picture methods was carried out to determine the flow regime transition criteria in the post-CHF region. An idealized inverted annular flow was obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas exit velocities were 0.05 to 0.5 and 0.03 to 7.9 m/s. Nitrogen and helium were used in the study. For the present configuration, there are four basic flow regimes. Beginning from the nozzle exit, there is a smooth, inverted annular flow section with liquid in the core and gas in the annulus; followed by the rough wavy section with an intact liquid core, the agitated and the dispersed flow regimes. For a given liquid jet velocity, the axial ...
A visual study of film boiling using photographic and high speed motion-picture methods was carried out to determine the flow regime transition criteria in the post-CHF region. An idealized inverted annular flow was obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas exit velocities were 0.05 to 0.5 and 0.03 to 7.9 m/s. Nitrogen and helium were used in the study. For the present configuration, there are four basic flow regimes. Beginning from the nozzle exit, there is a smooth, inverted annular flow section with liquid in the core and gas in the annulus; followed by the rough wavy section with an intact liquid core, the agitated and the dispersed flow regimes. For a given liquid jet velocity, the axial ...
This work presents an experimental and numerical study of pulsated Dean flow, three-dimensional pulsatile flow in a curved pipe. The numerical study is performed by CFD code (Fluent 6) in which a pulsated velocity field is imposed as an inlet condition. The experimental setup involves principally a 'Scotch-yoke' pulsatile generator and a 90o bend. Laser Doppler Velocimetry (LDV) measurements have shown that the Scotch-yoke generator produces pure sinusoidal instantaneous mean velocities with a mean deviation of 3%. Visualizations by laser-induced fluorescence (LIF) and velocity measurements, coupled with the numerical results, have permitted analysis of the evolution of the swirling secondary flow structures that develop along the bend during the pulsation phase. These measurements were made for a range of stationary Reynolds number (300?Rest?1200), frequency parameter (1??=r0(?/?)1/2max,osc/Ust). We observe satisfactory ...
In this paper, we report on the analysis of reverse flow in inverted U-tubes of a steam generator under natural circulation condition. The mechanism of reverse flow in inverted U-tubes of the steam generator with natural circulation is graphically analyzed by using the full-range characteristic curve of parallel U-tubes. The mathematical model and numerical calculation method for analyzing the reverse flow in inverted U-tubes of the steam generator with natural circulation have been developed. The reverse flow in an inverted U-tube steam generator of a simulated pressurized water reactor with natural circulation in analyzed. Through the calculation, the mass flow rates of normal and reverse flows in individual U-tubes are obtained. The predicted sharp drop of the fluid temperature in the inlet plenum of the steam generator due to reverse ...
Requirements for the installation, inspection, and testing that assure the quality of important components of a nuclear power plant during construction are presented.
A theoretical framework centering on four classes of self-referent constructs is offered as a device for integrating the diverse areas constituting medical sociology. Guidance by this framework...Full Text Available
On the basis of the resolvent of a simple differential operator, a method for finding approximations to continuous functions is constructed. In this method, both the approximated function and its approximations satisfy the given integral boundary condition.
A historical prospective mortality study was conducted on a cohort of 34 156 male members of a heavy construction equipment operators union with potential exposure to diesel exhaust emissions. This...Full Text Available
A novel approach to the Bragg curve spectroscopy is utilized to construct a charged particle detector which makes fragment elemental identification and energy measurement possible. The advantage of the construction includes good timing and spectroscopic properties with a very low energy threshold. ((orig.))
A previous study demonstrated the advantages that could be obtained in using loose liner naval gun barrel construction, particularly if the liner is autofrettaged. This report deals with the longitudinal forces required to assemble and disassemble such co...
In an era of unprecedented technological advancement and economic expansion, construction practice continues to evolve but construction education has not changed appreciably since the 1990s. This schism has prompted industry, government, and other key constituents to question the relevancy and efficacy of current programs. The Accreditation Board for Engineering and Technology (ABET) Engineering Criteria 2000 and the American Council for Construction Education (ACCE) emphasizes outcomes over process, and provides an opportunity for stakeholders to help universities define educational goals and objectives and design a curriculum to meet the desired outcomes. While the need for curriculum modification has been acknowledged, the industry position was amorphous and anecdotal and therefore difficult to address. Qualitative methodologies such as formal surveys and structured interviews can be used to capture and quantify industry ...
A substantial design and development program has been underway in the United States of America on the Darrieus vertical axis wind turbine (VAWT). The purpose of this report is to present currently available information on: design, construction, and testin...
Gentilly 2, Point Lepreau, Cordoba and Wolsung are the first 600 MW CANDU nuclear generating stations to be built. Progress in their construction and in the remaining design work for these stations is discussed. (LL).
The computer aided coal structure construction system is proposed, and a computational construction example is presented. The coal structure construction engine of this system fabricates molecular structure by connecting fragments sequentially inputted through a user interface. The best structure candidate is determined using construction knowledge and partial energy evaluation every addition of one fragment, and this process is subsequently repeated. The structure evaluation engine analyzes the 3-D conformation candidate by molecular dynamics, and evaluates the conformation by determining the energy value of an optimum structure. As an example, this system was applied to construction of coal molecular structure based on the actual data of partial structure composed of 26 structures from 2l kinds of aromatic cluster structures, 27 bonds from 2 kinds of bridged bonds, and 16 groups ...
Thermodynamic Stable Metal Compositions for Improvement of an Operational Safety of Constructional Materials under Conditions of Multifactor Loadings of an Aggressive Environment
Project management mode plays a key role in project construction, especially in nuclear power field. From the aspects of right, responsibility and benefit, this paper discussed the differences among the common used project management modes. Also the main kinds of the construction management modes used in China's nuclear power plants were summarized. At last, considering the experience of Ningde nuclear power plant, this paper put forward several perspectives about the selection of project management mode in nuclear power plant construction. (authors)
Discusses design of unconventional pneumatic forms for construction of monolithic liners in mine roadways driven by drilling and blasting. The forms were developed for construction of the municipal subway in Leningrad. They were successfully tested in the Pavlogradugol' mines for construction of chambers situated at shaft bottom at depths of 420 m. The chambers were situated in unstable rock strata. A set of pneumatic forms consisted of 4 to 7 units, each 0.4 m thick and 1.2-2.2 m long. Air pressure was 0.03 MPa, installation time was about 20 min. Service life of pneumatic forms ranged from 3 to 4 years.
Innovative new ideas for the construction of homes are described. A thermal energy storage system fireplace and a geothermal heat pump for homes are described.
Nanoparticles represent versatile building blocks in material science and nanotechnology. Thereby, the defined assembly of nanostructures (13 and 56 nm in diameter, respectively) is of significant importance. Short DNA sequences can be bound to the nanoparticle surface thus enabling highly specific DNA hybridization-driven events that direct the formation of nanoparticle constructs.In this paper, examples for the defined formation of gold nanoparticle constructs are demonstrated. In addition, gold-silver core-shell nanoparticles are introduced as further building blocks for the hybridization-controlled formation of nanoparticle constructs.
... concentrated on the construction of switches using fiber ... been chosen for a switch realized in ... of these techniques using acousto-optic modulators or ...
... nent to the design and construction of metal-semiconductor solar cells, in that both the photovoltage and the efficiency of metal-semiconductor cells ...
Three types of drift chambers are being constructed for the Fermilab D/O/ experiment. The construction and readout of these chambers stress good spatial resolution, good two hit separation, and dE/dx. A 106 MHz FADC system with hardware zero suppression is being constructed to readout this system. 8 refs., 12 figs., 1 tab.
The Lowell Hydroelectric Project (Eldred L. Field) is a key feature of the Departments of Energy's National Low Head Hydroelectric Power Demonstration Program. This report summarizes the Project's Construction which began in October 1983 and was completed in November 1985. It also details project construction costs.
Appendix B to 10 CFR Part 50 establishes overall quality assurance requirements for the design, construction and operation of safety-related structures, systems, and components. This guide presents a method acceptable to the Commission for complying with these regulations with regard to overall quality assurance program requirements during design and construction of nuclear power plants. Input to this guide has been provided by the Advisory Committee on Reactor Safeguards.
The special geodetic problems encountered during the construction of the Paks nuclear power plants are treated. The main building with its hermetically connected components including the reactor, the steam generators, the circulation pumps etc. impose special requirements on the control net of datum points. The geodesy tasks solved during the construction of the main building are presented in details.
Multi-dimensional modelling of two-phase flow requires accurate constitutive relationships for interfacial parameters such as interfacial heat transfer, void fraction distribution, interfacial area, etc. However, existing diagnostic systems for measurement of two-phase flow parameters have difficulty measuring two or three-dimensional void distributions required for determination of interfacial parameters. In this work, a Real-Time Neutron Radiography (RTNR) system is developed for non-intrusive measurement of two-phase flow parameters in nuclear fuel channels at low thermal neutron fluxes (on the order of 10{sup 6}n/cm{sup 2}-s). This advanced radiation technique has the advantage of measuring two-phase flow in 3 1/2 dimensions (x,{integral}dy,t) where the 1/2 dimension refers to an integrated or averaged space dimension. Pipe flow channels, annulus flow ...
Multi-dimensional modelling of two-phase flow requires accurate constitutive relationships for interfacial parameters such as interfacial heat transfer, void fraction distribution, interfacial area, etc. However, existing diagnostic systems for measurement of two-phase flow parameters have difficulty measuring two or three-dimensional void distributions required for determination of interfacial parameters. In this work, a Real-Time Neutron Radiography (RTNR) system is developed for non-intrusive measurement of two-phase flow parameters in nuclear fuel channels at low thermal neutron fluxes (on the order of 10"6n/cm"2-s). This advanced radiation technique has the advantage of measuring two-phase flow in 3 1/2 dimensions (x,#integral#dy,t) where the 1/2 dimension refers to an integrated or averaged space dimension. Pipe flow channels, annulus flow channels, ...
Numerical results on aeroelastic standard configurations are presented. The methods used for two dimensional configurations include the small perturbations approach for inviscid flow, coupling methods for unseparated flow, coupling methods for unseparated or separated, laminar or turbulent boundary layers, and a numerical solution of the Euler equations for inviscid flow. The three dimensional configurations are studied by the transonic small disturbance approach. The detailed results are given.
A theoretical analysis of two-dimensional unsteady flow in a porous medium bounded by a horizontal wall is presented as a perturbation on a basic flow. It is assumed that the perturbation is occasioned by a sudden suction at the wall. Even for a highly permeable medium the characteristic Reynolds number in porous media flow is usually small and asymptotic solutions are developed by the Laplace transform technique. It is observed that the perturbed shear stress at the wall decays exponentially with time. (author). 5 refs.
A series of real-time, neutron radiography, experiments are ongoing at the Texas A and M Nuclear Science Center Reactor (NSCR). These tests determine the resolving capabilities for radiographic imaging of two phase water and air flow regimes through small diameter flow channels. Though both film and video radiographic imaging is available, the real-time video imaging was selected to capture the dynamic flow patterns with results that continue to improve. (author)
We apply our work on fracture- and matrix-dominated flow to develop a conceptual model of hydrological flow processes in the unsaturated zone at Yucca Mountain. The possibility of fracture-dominated flow is discussed, and various deductions are made on its impact on natural and total system performance, site characterization activities, and site suitability determination.
The presentation deals with the flows on the primary side of a horizontal steam generator under conditions typical to natural circulation cooling of the reactor. The main goal is to analyse the effect of primary flow patterns on the heat transfer capability of the steam generator. Conclusions pertinent to steam generator modelling with system codes are also drawn. (10 refs., 9 figs., 4 tabs.).
The presentation deals with the flows on the primary side of a horizontal steam generator under conditions typical to natural circulation cooling of the reactor. The main goal is to analyse the effect of primary flow patterns on the heat transfer capability of the steam generator. Conclusions pertinent to steam generator modelling with system codes are also drawn. (10 refs., 9 figs., 4 tabs.).
The seawater in the intake structure flows into the large pump to with draw excess heat from the turbine steam condenser. In the intake structure of a nuclear power plant, undesirable pump operating characteristics such as vortices, impeller damages and non-uniform pump-approach flow around the pump bells take place frequently due to poorly-arranged intake geometry. In this study, physical modeling test was performed to predict the hydraulic phenomenon, and proposed flow control devices.
A numerical calculation procedure applicable to cavity-type receiver configurations and flow conditions was developed. Flow visualization experiments were performed, and experimental measurements of quantities valuable for the development of the numerical calculation procedure were made. The investigation is focussed on a configuration which is strongly two-dimensional in the mean flow structure (but turbulent in a truly three-dimensional sense). (LEW)
Transonic flows with heat addition due to condensation are important to many technical applications, e.g. to the last stages of large steam turbines, where nucleation and droplet formation become important. Our current research concentrates on the interaction of vortex shedding with condensation in turbines and on rotor/stator interaction in nucleating flows. Both phenomena lead to a significant change of the condensate mass and the droplet radius distribution in the downstream two-phase flow regime. (orig.)
Heat transfer augmentation by straight grid spacers in rod bundles is studied for single phase flow and for post critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single phase flow is also examined. Governing heat transfer mechanisms are analyzed, and predictive formulations are established. For single phase flow, the local heat transfer at a straight spacer and at its upstream or downstream locations are treated separately. 18 refs.
Two sets of analytical correlations describing transitions between two-phase flow regimes are reviewed and discussed. One, the T-D set, is based on mechanistic models; the other, the Weisman set, on experimental correlations. The T-D set is preferred for horizontal flow, whereas the Weisman set seems preferrable for vertical flow. A computer code (FLOP) based on the T-D theory is described and applied to validate the theory.
Several aspects of heat transfer at the annular two phase flow regime are considered. Nucleate boiling is supposed to be absent. Theoretical solutions for cases of laminar and turbulent flow in the liquid film, respectively, are considered, when steam presence does not effect the heat transfer. Heat transfer in annular flows is also considered, where steam phase consists totally or partially of the so-called incondensable gas. In this case steam phase can be a considerable resistance to heat transfer.
A numerical method for the calculation of unsteady, inviscid turbomachine flow in the transonic velocity range is described. The calculation of complete stages is possible. If the flow layer geometry is given, the flow field can be determined by independe...
The purpose of the work described in this dissertation is to increase the understanding of injection-pultrusion process. Three major substudies related to injection-pultrusion have been completed: measurement of the compressibility of fiber reinforcements, measurement of in-plane and transverse resin flow through fiber reinforcements, and development of a resin flow model. This dissertation also presents results of an experimental and analytical investigation of in-plane and transverse resin flow through fiber reinforcements.
This report summarizes work performed on this project from October 2004 through March 2005. In previous work, a surfactant modified zeolite (SMZ) was shown to be an effective system for removing BTEX contaminants from produced water. Additional work on this project demonstrated that a compost-based biofilter could biodegrade the BTEX contaminants found in the SMZ regeneration waste gas stream. However, it was also determined that the BTEX concentrations in the waste gas stream varied significantly during the regeneration period and the initial BTEX concentrations were too high for the biofilter to handle effectively. A series of experiments were conducted to determine the feasibility of using a passive adsorption column placed upstream of the biofilter to attenuate the peak gas-phase VOC concentrations delivered to the biofilter during the SMZ regeneration process. In preparation for the field test of the SMZ/VPB treatment system in New Mexico, a pilot-scale SMZ system was also ...
ObjectivesThe objective of this meeting will be to interface the two ends of the particulate flow spectrum - those working to understand the fundamentals of granular flows and those attempting to control particulate flows in an industrial setting - to develop solutions to the complex problems presented by dense granular flows. We will aim~%~~%~to provide a forum for the interface between practical users of particulate technology and the developers of theories for understanding granular flow;~%~to present [continued...]DescriptionIn practical situations such as those met in industry where segregation and mixing are important, understanding particulate flows is complex due to the presence of polydispersity, anisotropy and complex grain morphology. In attempting to model such systems, many of these features are generally ignored, except perhaps ...
In this study, the effects of channel surface wettability, cross-sectional geometry and orientation on the two-phase flow in parallel gas channels of proton exchange membrane fuel cells (PEMFCs) are investigated. Ex situ experiments were conducted in flow channels with three different surface wettability (hydrophilically coated, uncoated, and hydrophobically coated), three cross-sectional geometries (rectangular, sinusoidal and trapezoidal), and two orientations (vertical and horizontal). Flow pattern map, individual channel flow variation due to maldistribution, pressure drop and flow visualization images were used to analyze the two-phase flow characteristics. It is found that hydrophilically coated gas channels are advantageous over uncoated or slightly hydrophobic channels regarding un...
Object: To permit a valve operation test to be periodically made during plant operation without causing variations in plant power by detecting flow control valve defect on the basis of a valve aperture alteration instruction. Structure: Step signals which are equal in absolute value and opposite in sign are coupled to the input side of flow controllers provided on the recycling loops of two or more recycling flow control systems. With these inputs the aperture of the flow control valve on one side is increased (or reduced) while the aperture of the valve on the other side is reduced (or increased). As a result, the recycling flow rate in the loop on one side is increased (or reduced) while that on the other side is reduced (or increased). Whether the valve is normally operating or not is confirmed by checking the recycling flow rate and valve aperture. ...
The wind turbines with a flanged-diffuser shroud-so called ?wind lens turbine??-are developed as one of high performance wind turbines by Ohya et al. In order to investigate the flow characteristics and flow acceleration, the paper presents the flow velocity measurements of a long-type and a compact-type wind turbines with a flanged-diffuser shroud by particle image velocimetry. In the case of the long type wind turbine, the velocity vectors of the inner flow field of the diffuser for turbine blades rotating and no blades rotating are presented at Reynolds number, 0.9?105. Furthermore the flow fields between with and without rotating are compared. Through the PIV measurement results, one can realize that the turbine blades rotating affects as suppress the disturbance and the flow separatio...
There are two difficulties encountered in modeling valveless micropumps using lumped-element methods. The pressure loss coefficient for fluidic diodes used in valveless pumps to rectify flow depends on the flow direction. A problem arises in choosing the proper loss correlation because the flow direction is not known a priori. Another problem is the quadratic form of the equation for the flow through the fluidic diodes, which brings about multiple solutions. The above problems become even more serious in multi-chamber cases. They are overcome in this study by suitably formulating the flow resistance. In addition, the flow inertia is accounted for in the unsteady model. The steady and unsteady models are evaluated by comparing with CFD simulations, which also serve to illustrate the flow fi...
Turbulent shear flows on shallow continental shelves (here shallow means that the interaction with the solid, no-slip bottom is important) are of great importance because tide- and wind-driven flows on the shelf are drivers of the transfer of momentum, heat, and mass (gas) across the air?sea interface. These turbulent flows play an important role because vertical mixing and current are vectors for the transport of sediment and bioactive material on continental shelves. Understanding the dynamics of this class of flows presents complications because of the presence of a free surface and also because the flow can be driven by a pressure gradient (a tidal current), a stress at the free surface (a wind-driven current), or a combination of both. In addition, the flow can be modified by the pres...
Hydrological classification constitutes the first step of a new holistic framework for developing regional environmental flow criteria: the ?Ecological Limits of Hydrologic Alteration (ELOHA)?. The aim of this study was to develop a classification for 390 stream sections of the Segura River Basin based on 73 hydrological indices that characterize their natural flow regimes. The hydrological indices were calculated with 25?years of natural monthly flows (1980/81?2005/06) derived from a rainfall-runoff model developed by the Spanish Ministry of Environment and Public Works. These indices included, at a monthly or annual basis, measures of duration of droughts and central tendency and dispersion of flow magnitude (average, low and high flow conditions). Principal Component Analysis (PCA) indi...
The concepts of general flow and thermal boundary conditions are introduced to treat the interaction between indoor and outdoor thermal environments in computational fluid dynamics (CFD) simulations. The results from a multi-zone model are used to supply the general flow boundary conditions. The energy balance equation at wall-air interfaces is used to supply the general thermal boundary conditions. An example calculation in a 13-room building shows that infiltration influences indoor air flow patterns considerably. The air flow in a room ventilated by displacement is measured and simulated. Two surface coatings are considered, i.e. black walls and aluminum walls. Implementation of these two boundary conditions is essential in predicting air flow patterns, air quality, and thermal comfort in a real building. (author)
The present paper deals with the experimental determination of pressure drop across a four-cusped vertical channel. This geometry represents, ideally, the blockage condition in a typical pressurized water reactor with core degraded by accident. Experiments were performed for both single and two-phase flow. Water was utilized for the single-phase measurements whilst simultaneous flow of air and water simulated the steam-water flow. Observation of the prevailing two-phase flow regime was carried out, so that its mechanism could be fully understood. The averaged void fraction was also measured, by the gamma-ray attenuation technique. A wide range of water and air mass flow rates was covered, so that all flow conditions, possible to exist in a reactor with LOCA, could be investigated. New correlations for pressure drop are proposed. (Author).
A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,{theta}) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug ...
A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,#theta#) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug ...
A safety analysis code to design a pressurized water reactor and to obtain the licences including entire proprietary rights is under development in domestic research and development project. The purpose and scope of this report is to develop the flow regimes related models for inter-phase friction, wall frictions, wall heat transfer, and inter-phase heat and mass transfer in two-phase three-field equations. In order to choose choose the flow regime criteria, we have investigated various exiting best-estimate T/H codes in this chapter 2. They are the RELAP5-3D, TRAC-M, CATHARE, MARS codes. Around 500 references used in these codes have been collected and reviewed. Also we have investigated eleven papers in detail. In chapter 3, based on the selected flow regimes, the flow regime maps for a gas-liquid flow in horizontal and vertical tubes have decided including the mechanisms of ...
A safety analysis code to design a pressurized water reactor and to obtain the licenses including entire proprietary rights is under development in domestic R and D project. The tasks of KAERI is to develop the constitutive relations including models for defining flow regimes and flow regime related models for inter-phase friction, wall frictions, wall heat transfer, and interphase heat and mass transfer in the two-phase three-field equations. In this paper, the process will be presented for choosing the best flow regime maps which occur in gas-liquid two-phase flow in horizontal and vertical tubes.
A safety analysis code to design a pressurized water reactor and to obtain the licenses including entire proprietary rights is under development in domestic R and D project. The tasks of KAERI is to develop the constitutive relations including models for defining flow regimes and flow regime related models for inter-phase friction, wall frictions, wall heat transfer, and interphase heat and mass transfer in the two-phase three-field equations. In this paper, the process will be presented for choosing the best flow regime maps which occur in gas-liquid two-phase flow in horizontal and vertical tubes.
We have developed EOS7M, a ferrofluid flow and transport module for TOUGH2. EOS7M calculates the magnetic forces on ferrofluid caused by an external magnetic field and allows simulation of flow and advective transport of ferrofluid-water mixtures through porous media. Such flow problems are strongly coupled and well suited to the TOUGH2 framework. Preliminary applications of EOS7M to some simple pressure and flow problems for which experiments were carried out in the lab show good qualitative agreement with the laboratory results.
A radial-flow type internally oil-cooled oil-filled cable has been developed. This system is characterized in that the oil flows radially through the paper insulation. The thermal resistance of the insulation is equivalently decreased by the radial-flow. The decreased thermal resistance as well as the cooling effect of the oil flow in the central oil duct and the outer oil duct under an aluminum sheath increase the current capacity. A calculation method of cooling characteristics is introduced. The stability of the cable and accessories was confirmed through initial electrical tests and a long-term field test.
The development of new electro-optical instrumentation for studying the annular dispersed two-phase flow regime is described. The system measures the thickness of the water film and droplet size and velocity distributions which would be encountered in such a flow regime. The water film thickness is measured by an improved capacitance method with a short time constant using newly developed sensor electrodes. The electrodes are made flush with the inner wall of a cylindrical tube and do not disturb the flow. In the test equipment, steady, laminar flow of water along the inner wall of the tube is controlled by appropriate valves and a porous jacket while droplets are introduced by means of a special spray nozzle.
A diagnosis of the refrigerant flows in a refrigerator was carried out by real-time neutron radiography. The thermal neutron radiography system of JRR-3M in Japan Atomic Energy Research Institute and the real-time image processing system developed by Musashi Institute of Technology were used. Freon evaporating flows in the evaporator, condensing flows in the condenser, flashing flows in the capillary tube and flows in the accumulator were visualized and the dynamic behaviors under practical conditions were clarified. In the case of the capillary tube of 0.8 mm i.d., a cooled-CCD camera was utilized. (orig.).
In the design of natural gas compressor stations, a check valve is a critical element which is commonly placed on the discharge side of the compressor to prevent reverse flow that can cause serious damage to the compressor itself and other components such as seals and bearings. One of the selection criteria of the check valve for this particular application is the valve flow characteristics in steady flow, and its dynamic characteristics in unsteady flow operation. With regards to steady flow valve characteristics, current models for the determination of the check valve open angle vs. mean flow velocity are based on semi-empirical data obtained from water tests, which were found to deviate from measurements in compressible flows. This paper presents results of steady compressible flow testing of an NPS 4 swing type check ...
The following paragraphs summarize the progress of each research project funded under the WVU Cooperative Agreement during the third quarter of 1997 (July - September 1997). The projects are arranged according to their 1997 WVU task number. WVU Focus Area 1.0: Subsurface Contaminants, Containment and Remediation Task No. 1.1: Project discontinued. Task No. 1.2: Development of Standard Test Protocols and Barrier Design Models for Desiccation Barriers (K. Amininan & S. Ameri): A number of experiments were preformed this period to evaluate the ability of the dried sand-packs to act as a barrier to liquids. Water infiltration tests were done with a constant head, dispersing 80 ml of water, and by adding water in small increments. Results indicate that when the water is spilled over the sand-pack, it has the tendency to channel through the sand-pack, significantly reducing the capacity of the dried zone to retain liquid contaminants. This appears to be largely influenced by particle ...
The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead composite material were investigated. The material containing 20-30 vol.% of lead had optimal combination of mechanical and electrochemical properties. Optimal process parameters to manufacture the anodes were identified. Prototypes having ...
Site studies for CANDU type NPP began in a careful manner since 1982 as a first part of the Nuclear Power Plant Romanian Program adopted by political and governmental authorities at the time. A team was charged to develop all packages of the necessary main studies. The first Romanian NPP CANDU 6 type reactor gone to erection on Cernavoda site, planned to have 5 units and, like Wolsong NPP, applied the same design for the nuclear island. For the BOP parts the ANSALDO-GE project was applied with a thorough concern about requirements raised by connection to NSP. The first mission of design and research multi-branch team was to adapt the NPP Cernavoda project having an open water cooling circuit 'once-through' to the new parameters of a close recirculation water cooling circuit. Also, the structural design was re-evaluated for the case of soft foundation strata instead of hard rock ones. The close recirculation water cooling circuit system was applied for PWR NPP type like in French or ...
Leakage of CO{sub 2} and displaced brine from geologic carbon sequestration (GCS) sites into potable groundwater or to the near-surface environment is a primary concern for safety and effectiveness of GCS. The focus of this study is on the estimation of the probability of CO{sub 2} leakage along conduits such as faults and fractures. This probability is controlled by (1) the probability that the CO{sub 2} plume encounters a conductive fault that could serve as a conduit for CO{sub 2} to leak through the sealing formation, and (2) the probability that the conductive fault(s) intersected by the CO{sub 2} plume are connected to other conductive faults in such a way that a connected flow path is formed to allow CO{sub 2} to leak to environmental resources that may be impacted by leakage. This work is designed to fit into the certification framework for geological CO{sub 2} storage, which represents vulnerable resources such as potable groundwater, health and safety, ...
Smoke management in buildings during fire events often uses mechanical ventilation systems to maintain smoke layer elevation above a safe evacuation path. Design of these systems requires accurate correlations for the smoke production rate of the buoyant fire plume. One design issue is the smoke production rate of fire plumes which spill out from a fire compartment, under a balcony and up through an atrium or other large volume. Current engineering correlations for these balcony spill plumes are based on a combination of one-tenth scale test data and theoretical analysis. Questions have arisen over the suitability of these correlations for real-scale designs. A combined program of full-scale experimentation and CFD modeling is being conducted to analyze the accuracy of these correlations. A full-scale experimental facility was constructed with a 5 m by 5 m by 15 m fire compartment connected to a four-story atrium. Propane fires in the compartment produce balcony ...
Smoke management in buildings during fire events often uses mechanical ventilation systems to maintain smoke layer elevation above a safe evacuation path. Design of these systems requires accurate correlations for the smoke production rate of the buoyant fire plume. One design issue is the smoke production rate of fire plumes which spill out from a fire compartment, under a balcony and up through an atrium or other large volume. Current engineering correlations for these balcony spill plumes are based on a combination of one-tenth scale test data and theoretical analysis. Questions have arisen over the suitability of these correlations for real-scale designs. A combined program of full-scale experimentation and CFD modeling is being conducted to analyze the accuracy of these correlations. A full-scale experimental facility was constructed with a 5 m by 5 m by 15 m fire compartment connected to a four-story atrium. Propane fires in the compartment produce balcony ...
A proton exchange membrane fuel cell (PEMFC) must maintain a balance between the hydration level required for efficient proton transfer and excess liquid water that can impede the flow of gases to the electrodes where the reactions take place. Therefore, it is critically important to understand the two-phase flow of liquid water combined with either the hydrogen (anode) or air (cathode) streams. In this paper, we describe the design of an in situ test apparatus that enables investigation of two-phase channel flow within PEMFCs, including the flow of water from the porous gas diffusion layer (GDL) into the channel gas flows; the flow of water within the bipolar plate channels themselves; and the dynamics of flow through multiple channels connected to common manifolds which maintain a uniform pressure differential across all possible ...
The two-phase flow regime transition in a large diameter (I.D.=200mm) vertical pipe was experimentally investigated using a dual-sensor optical probe. The flow transitions from bubbly to chum without an intermediate slug flow regime as the air flow rate is increased. The transition boundaries developed for bubbly to slug flow in small diameter pipes are compared to the bubbly to chum flow transition of the present experiment. The bubbly to chum transition occurs at a void fraction of about 0.15 compared to 0.25 for bubbly to slug transition in small diameter pipes. The radial distribution of bubble diameter, bubble frequency, bubble velocity and local void fraction were obtained using a dual-sensor optical probe at different flow conditions. The Probability Density Function (PDF) and Cumulative Distribution Function (CDF) of the bubble ...
The two-phase flow regime transition in a large diameter (I.D.=200mm) vertical pipe was experimentally investigated using a dual-sensor optical probe. The flow transitions from bubbly to chum without an intermediate slug flow regime as the air flow rate is increased. The transition boundaries developed for bubbly to slug flow in small diameter pipes are compared to the bubbly to chum flow transition of the present experiment. The bubbly to chum transition occurs at a void fraction of about 0.15 compared to 0.25 for bubbly to slug transition in small diameter pipes. The radial distribution of bubble diameter, bubble frequency, bubble velocity and local void fraction were obtained using a dual-sensor optical probe at different flow conditions. The Probability Density Function (PDF) and Cumulative Distribution Function (CDF) of the bubble ...
Liquid metal cooling for the first wall and blanket of a magnetic confinement fusion reactor has various advantages. However, it has the disadvantages of large magnetohydrodynamic pressure drops and heat transfer deterioration under a strong magnetic field. Thus, the present authors have proposed cooling with a helium-lithium annular mist flow as well as the cooling with a liquid metal boiling flow, and as fundamental studies, investigated the effect of a magnetic field on the flow characteristics and heat transfer of liquid metal two-phase systems since the 1970s. In the present paper we summarize the important findings obtained from our experimental studies for (i) an air-mercury stratified flow in a horizontal rectangular channel, (ii) a helium-lithium annular mist flow in a horizontal rectangular channel, (iii) the mercury pool boiling on a horizontal surface, and (iv) ...
Liquid metal cooling for the first wall and blanket of a magnetic confinement fusion reactor has various advantages. However, it has the disadvantages of large magnetohydrodynamic pressure drops and heat transfer deterioration under a strong magnetic field. Thus, the present authors have proposed cooling with a helium-lithium annular mist flow as well as the cooling with a liquid metal boiling flow, and as fundamental studies, investigated the effect of a magnetic field on the flow characteristics and heat transfer of liquid metal two-phase systems since the 1970s. In the present paper we summarize the important findings obtained from our experimental studies for (i) an air-mercury stratified flow in a horizontal rectangular channel, (ii) a helium-lithium annular mist flow in a horizontal rectangular channel, (iii) the mercury pool boiling on a horizontal surface, and (iv) ...
It is shown that the physical interpretation of Elie Cartan three-dimensional space torsion as couple asymmetric stress, has the effect of damping, previously Riemannian unstable Couette planar shear flow, leading to stability of the flow in the Lagrangean sense. Actually, since the flow speed is inversely proportional to torsion, it has the effect of causing a damping in the planar flow atenuating the instability effect. In this sense we may say that Cartan torsion induces shear viscous asymmetric stresses in the fluid, which are able to damp the instability of the flow. The stability of the flow is computed from the sectional curvature in non-Riemannian three-dimensional manifold. Marginal stability is asssumed by making the sectional non-Riemannian curvature zero, which allows us to determine the speeds of flows able to induce this ...
Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event ...
Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event ...
The purpose of the study is to investigate the heat transfer augmentation method for a wavy channel type heat exchanger. Experimental studies were carried out, by installation of flow guide-plates with simple structure, to clarify the effects on the augmentation whether the effects are brought by the flow acceleration or by the increase of intensity of turbulence due to the flow seperation, and to determine optimum shape of flow guide-plates. The shape and dimensions of the experimental apparatus are as follows; channel width H of 30 mm, rectangular section with breadth of 300 mm, wavy duct with a bend angle of 60/sup 0/ and straight pipe of 2H length. Air stream was flowed through the duct with Reynolds number of 1.7 x 10/sup 4/ only. As the results, following conclusions were obtained. (1) Wavy duct with large bend angle and without inserting flow guide-plates ...
The core of Prismatic Modular Reactor (PMR) consists of assemblies of hexagonal graphite fuel and reflector elements. The core bypass flow of Very High Temperature Reactor (VHTR) is defined as the core flow that does not pass through the coolant channels but passes through the bypass gap between fuel elements. The increase in bypass flow makes the decrease in effective coolant flow. Since the core bypass flow has a negative impact on safety and efficiency of VHTR, core bypass phenomena have to be investigated to improve the core thermal margin of VHTR. For this purpose, the international project, I-NERI project, has been carried out since 2008. I-NERI project is collaborative project that KAERI and SNU of Korea side and INL, ANL and TAMU of U.S side are involved. In order to evaluate the core bypass flow, the multicolumn and multi-layer experimental facility is ...
The marine reactor MRX, an integral typed PWR with 100 MWt adopts one-through steam generators with coiling tubes. The cold feed water enters the steam generator and the super heated steam flows out. To avoid occurrence of flow instability in the steam generator due to a density wave oscillation, it is necessary to increase of flow resistance at the feed water inlet. The magnitude of flow resistance to stabilize the flow is determined by a simple linear analysis using a D-division method, of which accuracy is clarified by comparison with SRI's experiment. The external force due to heaving, one of ship motions will affect the flow behavior. Analysis by a modified RELAP5 capable of simulating the ship motions reveals that the effect of heaving becomes especially greater when the state of flow approaches both the conditions of density ...
The Computational Fluid Dynamics(CFD) study was conducted to assess the new design concept introduced to solve the issues on the flow deviation between SG cassettes and the supporting structure design of the flow distributing plate subjected to the flow induced vibration. Flow field from MCP to the bottom of SG was modeled for 2-dimensional(2D) CFD analysis and then sensitivity analysis on major design parameters was conducted using commercial CFD code, Fluent. The cases for detailed 3D analysis were selected based on the result of 2D analysis and the detailed 3-dimensional(3D) analysis was conducted for these selected cases using Fluent code. Flow field was modeled by RNG model and wall function, 2nd upwind scheme, porous model, structured or hybrid grid. The analysis result shows that the maximum deviation of flow distribution between SG cassettes was reduced ...
Although incompressible fluid flows can be regarded as a particular case of a general problem, numerical methods and the mathematical formulation aimed to solve compressible and incompressible flows have their own peculiarities, in such a way, that it is generally not possible to attain both regimes with a single approach. In this work, we start from a typically compressible formulation, slightly modified to make use of pressure variables and, through augmenting the stabilising parameters, we end up with a simplified model which is able to deal with a wide range of flow regimes, from supersonic to low speed gas flows. The resulting methodology is flexible enough to allow for the simulation of liquid flows as well. Examples using conservative and pressure variables are shown and the results are compared to those published in the literature, in order to validate the method. (author)
A descriptive model and design procedure for the DC electromagnetic flow coupler is developed based on a quasi-one-dimensional analysis previously developed for the DC electromagnetic pump. It is shown that for a particular flow coupler geometry, the total efficiency and the pressure gradients through the pump and generator depend on two parameters - the Hartmann number and the ratio of the pump flow rate to generator flow rate. Thus, for a fixed Hartmann number the efficiency depends only on the flow ratio. However, for a fixed pressure rise through the pump it is shown that the efficiency depends only on the Hartmann number. Nomographs showing the operating characteristics and critical design points are presented. Example calculations for a full-size unit, suitable for use in a liquid-metal cooled fast breeder reactor, are also discussed using the design nomographs.
A theory for the mass transfer process was developed. It was assumed that the largest convective motions in the flow control the rate of mass transfer. Measurements of mass transfer coefficients for the absorption of oxygen by water films were made for concurrent flows in a horizontal rectangular channel, and for concurrent and free-falling downflow in a one-inch pipe. The measured values of the Sherwood number for concurrent flows were up to three times as great as would be predicted from this relation. This increase in Sherwood number was correlated with a dimensionless group similar to a Martinelli parameter which is characteristic of two phase flows. An explanation for this effect is given in terms of the way that the scales of the convective motions are related to bulk flow parameters.
Decay heat removal capability under boiling condition was studied using an LMFBR fuel subassembly mockup loop. The sodium flow was driven by natural convection through the loop in which was installed a 37-pin bundle heated electrically over a length of 45 cm. The heat flux furnished by the pins was increased stepwise, upon which the two-phase flow regime changed from bubble to slug flow and then to annular or annular mist flow. Dryout occurred even in slug flow regime, but only momentarily, and permanent dryout was not observed before establichment of annular flow. A suitable criterion for permanent dryout is considered to be 0.5 average exit sodium vapor quality. The results indicated that upon occurrence of sodium boiling, the coolability of fuel subassembly would be maintained by natural convection after reactor shutdown. (author).
Thermal hydraulics of a liquid metal is important to design the blanket of a magnetic confined fusion reactor. Since a liquid metal has high thermal and electrical conductivity, the flow characteristics are often different from those of an ordinary liquid like water especially in thermal convection and under a magnetic field. It is difficult to simulate such flows in a liquid metal cooled blanket by water. Flow visualization is a popular method to study thermal hydraulics. Since most of metals are visible by neutron rays, neutron radiography is available to the flow visualization of a liquid metal. The purpose of this study is to develop a visualization technique of the flow in a liquid metal by real-time neutron radiography using the tracer and the dye injection methods. A real-time thermal neutron radiography system of JRR-3M in Japan Atomic Energy Research Institute was used for ...
Thermal hydraulics of a liquid metal is important to design the blanket of a magnetic confined fusion reactor. Since a liquid metal has high thermal and electrical conductivity, the flow characteristics are often different from those of an ordinary liquid like water especially in thermal convection and under a magnetic field. It is difficult to simulate such flows in a liquid metal cooled blanket by water. Flow visualization is a popular method to study thermal hydraulics. Since most of metals are visible by neutron rays, neutron radiography is available to the flow visualization of a liquid metal. The purpose of this study is to develop a visualization technique of the flow in a liquid metal by real-time neutron radiography using the tracer and the dye injection methods. A real-time thermal neutron radiography system of JRR-3M in Japan Atomic Energy Research Institute was used for ...
Purpose: To stably control the reactor water level so as not to cause excess water feeding in a BWR type reactor. Constitution: A flow control valve is disposed to the exit of a feedwater pump for a nuclear reactor and the valve is controlled by a flow regulator to maintain the water level constant in the reactor. A signal from a water level controller is inputted to the flow regulator to thereby control the flow rate control valve. In this case, the flow regulator remains in a saturated state just after the starting of the feedwater pump, in which the pump flowrate is at 100% to result in an excess water feeding condition. In view of the above, a feedback circuit is provided to the flow regulator so that the saturated state is eliminated and the water feeding can be controlled directly from the water level controller. (Kamimura, M.).
The investigation of steam, water, and air flow characteristics in horizontal channel is a part of major investigations program at the Lithuanian Energy Institute. The objective of this program is to identify condensation effects on two-phase flow stability and to predict conditions when rapid condensation could be induced in two-phase condensable flow. This article presents investigation of steam-water and air multiphase flow in nearly horizontal rectangular channel. The experimental data for pressure drop and interfacial and wall shear stresses in the channel with uniform distribution of void fraction are presented in this paper. Overall channel dimensions are length = 1.2 m, width = 0.02 m, height = 0.1 m; however, the test section was about 0.84 m in length. Three different flow types ...
As part of the EPRI Motor-Operated Valve (MOV) Performance Prediction Methodology, a System Flow Model (SFM) has been developed to determine the differential pressure (DP) across MOVs as they are stroked in typical power plant systems. Input to the SFM includes valve flow characteristics (such as flow coefficient) and system characteristics (such as pump head/flow curve). The primary output is differential pressure across the valve at each stroke position. The SFM was validated by comparison with test data from the EPRI Flow Loop Test Program. In this study, we calculated DP using SFM and performed DP test for four MOVs. Compared between calculated DP and test DP of four MOV, respectively good agreements are found. (author). 6 refs., 9 figs., 1 tab.
A hypothesis on the transition of a fully water-saturated coal bed methane reservoir from single-phase flow through unsaturated flow to the two-phase flow regime was developed and substantiated using field data. The concept of parameter measurement windows was introduced to obtain the required reservoir parameters from flow testing. A new empirical relationship for capillary pressure vs. saturation, referred to as the Fermi distribution, was developed and shown to fit the capillary pressure-saturation data for coal, sandstone, and other consolidated and unconsolidated materials. New approximate analytic solutions for flow to a sink from an infinite coal bed reservoir with desorbing methane have been developed and verified using numerical models for the following cases: (1) single-phase gas flow with desorption; (2) single-phase water flow in ...
Inverted annular flow can be visualized as a liquid jet-like core surrounded by a vapor annulus. While many analytical and experimental studies of heat transfer in this regime have been performed, there is very little understanding of the basic hydrodynamics of the post-CHF flow field. However, a recent experimental study was done that was able to successfully investigate the effects of various steady-state inlet flow parameters on the post-CHF hydrodynamics of the film boiling of a single phase liquid jet. This study was carried out by means of a visual photographic analysis of an idealized single phase core inverted annular flow initial geometry (single phase liquid jet core surrounded by a coaxial annulus of gas). In order to extend this study, a subsequent flow visualization of an idealized two-phase core inverted annular flow geometry (two-phase central jet ...
Characteristics of pressure drop and heat transfer have been investigated for a lithium single-phase flow and a helium-lithium two-phase flow in a horizontal conducting circular channel in the presence of a uniform transverse magnetic field up to 1.4 T as related to the lithium cooling for magnetic-confinement fusion reactors. By the application of the magnetic field to the lithium single-phase flow, remarkable heat transfer enhancement has been observed at the top wall due to the suppression of the mixed convection occurring in the low Peclet number range, while appreciable heat transfer deterioration appeared in the high Peclet number range. It has been confirmed that the helium-lithium two-phase flow can reduce the high magnetohydrodynamic (MHD) pressure drop in a lithium single-phase flow, and it can provide much better heat transfer performance than that in a helium ...
This paper describes a long term course of research into the fundamentals of two phase flow regime dynamics that had lead to a differential description of regime properties. The development has included experiment, microscale simulation, and mathematical averaging to produce a dynamic equation for interfacial area.
BackgroundWhile the gene flow in some organisms is strongly affected by physical barriers and geographical distance, other highly mobile species are able to overcome such constraints....Full Text Available
Related to other research on the effectiveness of flow boiling heat transfer augmentation using various types of turbulators this investigation comprises a definitive study of the effect of large discrete roughness elements on heat transfer over the entir...
Experimental results are presented for a new and unique heat transfer augmentation technique in tubes. The technique consists of inserting a porous mesh structure into the flow passage of the tube. Due to the increased degree of turbulence, both the singl...
The flow of water through a dam of fairly arbitrary shape is examined in the limit of large frictional drag on the flow. The relation of the problem to the one-phase Stefan problem and a problem of anodic smoothing is explored. Monotonicity and uniqueness...
Dippold, V., S. Mohler , Validation of the Wind-US Unstructured Flow Solver .... Hamed, A. and A. Mohamed, Assessment of Shock Induced Flow Separation and ...... Nozzles for Hypersonic Propulsion, NASA CR 185197, AGARD Symposium ...
Peak expiratory flow rate (PEFR) has been measured hourly from waking to sleeping in 29 workers with respiratory symptoms exposed to the fumes of soft soldering fluxes containing colophony (pine resin)....Full Text Available
Jul 8, 2008 ... This case involves the flow over the ONERA M6 wing. ... The wind tunnel tests are documented by Schmitt and Charpin in the AGARD Report AR-138 ... supersonic flow, shocks, and turbulent boundary layers separation). ...
1. Previous studies have shown that electrical stimulation (ES) of the guinea-pig cochlea causes a neurally mediated increase in cochlear blood flow (CBF). It is known that the centrifugal neuronal...Full Text Available
For supersonic plasma flow velocities, instead of the usual shelf-step profile seen for subsonic flow, an overdense bump and cavity is observed. The profile is stable for long times even for moderate power microwaves.
An optical flow gradient algorithm was applied to spontaneously forming networks of neurons and glia in culture imaged by fluorescence optical microscopy in order to map functional calcium signaling...Full Text Available
station in flowmeter used for mass flow calculation. Introduction. THE design .... length (as a result of a less conservative boundary-layer separation criterion), 2) slight ..... ical Flow, AGARD Conference Proceedings, No. 30, 1968. 5Kantrowitz ...
Analytical method of theoretical simulation of collective hydrodynamic instabilities of intensive flows of discrete radiators, interacting with each other only through the coherent fields of their spontaneous radiation in corresponding media was suggested...
Aiming at the non-stationary characteristics of differential pressure fluctuation signals of gas-liquid two-phase flow, and the slow convergence of learning and liability of dropping into local minima for BP neural networks, flow regime identification method based on Singular Value Decomposition (SVD) and Least Square Support Vector Machine (LS-SVM) is presented. First of all, the Empirical Mode Decomposition (EMD) method is used to decompose the differential pressure fluctuation signals of gas-liquid two-phase flow into a number of stationary Intrinsic Mode Functions (IMFs) components from which the initial feature vector matrix is formed. By applying the singular vale decomposition technique to the initial feature vector matrixes, the singular values are obtained. Finally, the singular values serve as the flow regime characteristic vector to be LS-SVM classifier and flow regimes ...
The oil production is largely transported in pipelines operating in two-phase flow regime. The predominant flow pattern is the slug flow, which is characterized by intermittent succession of liquid slugs followed by long gas bubbles. This paper addresses specifically to the capture of the intermittently feature of slug flows using a compressible slug tracking model. The intermittency rules the bubble to bubble interactions, defines the bubble coalescence rate, changes the size of the bubbles, alters the pressure drop among other flow properties. The inlet sizes and velocities of the bubbles and slugs are estimated based on experimentally determined distributions characterized by its mean value and standard deviation. The inlet intermittency, transmitted through the inlet boundary condition, results in a better match of the fluctuating flow properties along the ...
In the region of annular liquid film-mist flow, the behavior of the droplets formed from the liquid film and the rate of formation are the subjects to be clarified in connection with the forecast of dry-out point, which becomes a problem in the region of high dryness such as reactor cooling system and steam generators. Many researches have been performed on such problem in vertical tubes, but the characteristics in horizontal flow have not yet been sufficiently clarified. This series of research is to clarify various characteristics, such as the velocity of vapor phase, the flow rate distribution of droplets, the formation and adhesion of droplets and the structure of liquid film, in the region of liquid film-mist flow, where liquid film exists on the bottom of a horizontal rectangular channel, and vapor flow is accompanied by droplets. In this study, by the measurement of the ...
In the region of annular liquid film-mist flow, the behavior of the droplets formed from the liquid film and the rate of formation are the subjects to be clarified in connection with the forecast of dry-out point, which becomes a problem in the region of high dryness such as reactor cooling system and steam generators. Many researches have been performed on such problem in vertical tubes, but the characteristics in horizontal flow have not yet been sufficiently clarified. This series of research is to clarify various characteristics, such as the velocity of vapor phase, the flow rate distribution of droplets, the formation and adhesion of droplets and the structure of liquid film, in the region of liquid film-mist flow, where liquid film exists on the bottom of a horizontal rectangular channel, and vapor flow is accompanied by droplets. In this study, by the measurement of the ...
Experiments are performed to investigate the single-phase flow and flow-boiling heat transfer augmentation in 3D internally finned and micro-finned helical tubes. The tests for single-phase flow heat transfer augmentation are carried out in helical tubes with a curvature of 0.0663 and a length of 1.15 m, and the examined range of the Reynolds number varies from 1000 to 8500. Within the applied range of Reynolds number, compared with the smooth helical tube, the average heat transfer augmentation ratio for the two finned tubes is 71% and 103%, but associated with a flow resistance increase of 90% and 140%, respectively. A higher fin height gives a higher heat transfer rate and a larger friction flow resistance. The tests for flow-boiling heat transfer are carried out in 3D internally micro-finned helical tube with a curvature of 0.0605 and a length of 0.668 m. ...
To increase further the accuracy of flow regime and considering the non-stationary characteristics of differential pressure fluctuation signals of gas-liquid two-phase flow, the flow regime identification method based on recurrence quantification analysis (RQA) and multi-sensor data fusion techniques is put forward. First of all, the recurrence quantification analysis method is used to extract the nonlinear feature parameters of the differential pressure fluctuation signals of gas-liquid two-phase flow, and data fusion of feature layer is conducted by QRA feature parameters of differential pressure signals of three pressure measure intervals, and composes the fusion feature vectors. The fused characteristic vector are input into the support vector machine for identify flow regime. The identification results for four typical flow regimes of air-water two-phase ...
A technique was developed that permits fluid flow to be visualized even where the flow is completely shrouded by metal. The technique employs real-time neutron radiography, which is similar to x-ray radiography except a collimated beam of neutrons is used. Various combinations of neutron-opaque tracer materials were tested with neutron-transparent fluid. Neutron opaque tracers, such as solid particles, fluid droplets, and streaklines were imaged through metal walls as they convected in neutron-transparent ambient fluid. Visualization of bubbles/voids were evaluated for possible future applications. Surface-flow patterns were also imaged by using neutron-opaque tufts. These techniques were evaluated for image contrast, resolution, and the ability to accurately track fluid flow fields. The techniques were also modeled to optimize contrast in various flow configurations. Imaging ...
A technique was developed that permits fluid flow to be visualized even where the flow is completely shrouded by metal. The technique employs real-time neutron radiography, which is similar to x-ray radiography except a collimated beam of neutrons is used. Various combinations of neutron-opaque tracer materials were tested with neutron-transparent fluid. Neutron opaque tracers, such as solid particles, fluid droplets, and streaklines were imaged through metal walls as they convected in neutron-transparent ambient fluid. Visualization of bubbles/voids were evaluated for possible future applications. Surface-flow patterns were also imaged by using neutron-opaque tufts. These techniques were evaluated for image contrast, resolution, and the ability to accurately track fluid flow fields. The techniques were also modeled to optimize contrast in various flow configurations. Imaging ...
Objective: The aim of this study was to characterize using flow cytometry cultured human primary keratinocytes isolated from the epidermis and hair follicles by different methods. Methods:...Full Text Available
We present faster approximation algorithms for generalized network flow problems. A generalized flow is one in which the flow out of an edge differs from the flow into the edge by a constant factor. We limit ourselves to the lossy case, when these factors are at most 1. Our algorithm uses a standard interior-point algorithm to solve a linear program formulation of the network flow problem. The system of linear equations that arises at each step of the interior-point algorithm takes the form of a symmetric M-matrix. We present an algorithm for solving such systems in nearly linear time. The algorithm relies on the Spielman-Teng nearly linear time algorithm for solving linear systems in diagonally-dominant matrices. For a graph with m edges, our algorithm obtains an additive epsilon approximation of the maximum generalized flow and minimum cost generalized ...
The prediction of two-phase flow regime in the horizontal pipings during a loss-of-coolant accident (LOCA) is important for safety analysis of a pressurized water reactor (PWR). The flow regime transition conditions for a horizontal two-phase air-water flow were studied using a large-height, horizontal rectangular duct test section. The duct dimensions were 700 mm in height, 100 mm in width and 28.3 m in length. The experimental criterion for the flow regime transition from the stratified to slug flow regimes, in terms of the local void fraction and the non-dimensional gas-liquid relative velocity, agreed qualitatively with the prediction by the Mishima-Ishii model that is based on an idea that the interfacial waves with the largest growth rate will develop into a slug. However, the transition in the experiment occurred at systematically lower (by about 40 %) relative velocities ...
IntroductionFlow diversion is a new approach to the endovascular treatment of intracranial aneurysms which uses a high density mesh stent to induce sac thrombosis. These devices...Full Text Available
include modeling geometric complexities, coupling between the flow and the .... noted that the AGARD 445.6 wing data set, which has been widely used for .... higher-level computational aeroelastic code validations at transonic flow separation ...
Mar 1, 2011 ... The most interesting flow characteristics observed were the occasional appearance of steady, ... pressure gradient, rather than wall divergence angle, controlled flow separation. ... Report/Patent Number: AGARD-AG-19/P9 ...
There are various interesting semantics' (extensions) designed for argumentation frameworks. They enable to assign a meaning, e.g., to odd-length cycles. Our main motivation is to transfer semantics' proposed by Baroni, Giacomin and Guida for argumetation frameworks with odd-length cycles to logic programs with odd-length cycles through default negation. The developed construction is even stronger. For a given logic program an argumentation framework is defined. The construction enables to transfer each semantics of the resulting argumentation framework to a semantics of the given logic program. Weak points of the construction are discussed and some future continuations of this approach are outlined.
Due to the general market conditions, the construction of steam turbines was greatly reduced in 1987. As in 1986, it came to a downward movement. This situation will heighten in the coming years. The exploitation of devices, which are available by way of the development of EDP in computation, construction, production and operation, leads to considerable improvements. These improvements can only be employed gradually, due to the reduction in production. However, technological progress can be used economically in part in the restoration of old installations. Here turbine construction, the thermodynamical interpretation of gas and steam turbines, developments in the field of conduction technology, piping and materials are described. Also improvements in operation security and operation supervision of the installations is treated, as well as service and maintenance of the plants. (BR) With 131 refs.
All sections of the third edition of this well-known textbook have been revised and enlarged in consequence of the change-over to SI units. Numerous examples and illustrations have been included or replaced by new ones. The book considers the latest research results as well as the constructive developments of industrial steam turbine construction. On a scientific basis, this plain book imparts basic knowledge of the design, calculation, execution, condensation and performance in service of steam turbines of all types. The well-founded introduction, together with many calculated examples addresses the student as well as the engineer.
The LHC is designed to provide proton beams of 7 TeV and nominal luminosity of 10**34 cm**-2s**-1. This objective is achieved at an affordable cost by pushing all major collider components to the limits of technology, by upgrading the existing CERN accelerators and infrastructure, and by involving the technical expertise, resources and dedication of accelerator laboratories world-wide. Following a decade of intensive R&D and technical validation of major collider systems, the LHC construction is now fully underway. Major industrial contracts have been awarded and are in execution for the procurement of the magnet, cryogenics and other systems. In this report, the status of the design and construction of the major LHC systems is presented.
The Large Hadron Collider (LHC) project, approved by the CERN Council in December 1994, has now fully entered its construction phase, with the detailed technical definition of the major systems, and the adjudication of a number of large procurement contracts. We first recall the main features and characteristics of the LHC, report on the advances in definition of the layout and optics as well as on preparation of the injector complex, and review recent progress in the key technical systems of the main ring: magnets, cryogenics and vacuum, as well as civil construction, which has started following acceptance by authorities in the Host States.
Due to development of electric power system and considering an increase of electrical energy consumption, needs for larger units in new power plants are obvious. Connection of large nuclear power plants to the grid, depending on their power and location, usually requires significant investments in transmission network development and construction. Considering the capacity of the 400 kV transmission network in Croatia, this problem is evident. This paper deals with the possibilities of nuclear power plants construction, as one possible option in electric power system development, and their interconnection to the electricity grid. (author).
Several short model SSC 50 mm bore dipoles are being built and tested at Fermilab. Mechanical design of these magnets has been determined from experience involved in the construction and testing of 40 mm dipoles. Construction experience includes coil winding, curing and measuring, coil end part design and fabrication, ground insulation, instrumentation, collaring and yoke assembly. Fabrication techniques are explained and construction problems are discussed. Similarities and differences from the 40 mm dipole tooling and management components are outlined. Test results from the first models are presented. 19 refs., 12 figs.
This largely expository paper first gives an introduction to Hilbert stability and its use in Gieseker's GIT construction of $\\overline{M}_g$. Then I review recent work in this area--variants for unpointed curves that arise in Hassett's log minimal model program, starting with Schubert's moduli space of pseudostable curves, and constructions for weighted pointed stable curves and for pointed stable maps due to Swinarski and to Baldwin and Swinarski respectively. The focus is on the steps at which new ideas are needed. Finally, I list open problems in the area, particularly some arising in the log minimal model program that seem inaccessible to current techniques.
This construction curriculum guide on masonry for secondary students is one of six developed for inservice teachers at Marianas High School in Saipan. The guide provides the rationale, description, goals, and objectives of the program; the program of studies and performance objectives by levels; samples of lesson plans for effective delivery of instruction; and a listing of references. Concepts covered include orientation to masonry construction, safety, tools and equipment, cement, concrete, concrete block masonry, concrete forms, and concrete reinforcement. Appended materials include transparency copies, tests and answer keys, information sheets, and student activities. (CT)
In the construction work for the Unit No.5 Turbine Building at Hamaoka Nuclear Power Station, the collaboration work for the planning and the coordination of the building construction and the machinery installation was carried out utilizing three-dimensional computer aided design (3D CAD) information. It was the first time in Japan for a building constructor and a plant manufacturer to work together, exchanging 3D CAD data of the whole building and adjusting the construction schedule. It was made possible to confirm the correspondence concerning the planning of both companies from the primary stage of the project by the total process simulation and to adjust on-going work precisely by the partial process simulation.
In the construction work for the Unit No.5 Turbine Building at Hamaoka Nuclear Power Station, the collaboration work for the planning and the coordination of the building construction and the machinery installation was carried out utilizing three-dimensional computer aided design (3D CAD) information. It was the first time in Japan for a building constructor and a plant manufacturer to work together, exchanging 3D CAD data of the whole building and adjusting the construction schedule. It was made possible to confirm the correspondence concerning the planning of both companies from the primary stage of the project by the total process simulation and to adjust on-going work precisely by the partial process simulation.
In several recent papers on entanglement in relativistic quantum systems and relativistic Bell's inequalities, relativistic Bell-type two-particle states have been constructed in analogy to nonrelativistic states. These constructions do not have the form suggested by relativistic invariance of the dynamics. Two relativistic formulations of Bell-type states are shown for massive particles, one using the standard Wigner spin basis and one using the helicity basis. The construction hinges on the use of Clebsch-Gordan coefficients of the Poincare group to reduce the direct product of two unitary irreducible representations (UIRs) into a direct sum of UIRs.
Bubbly and slug flows have been analyzed using the afore-mentioned techniques. An image series of bubbly-slug flow is shown. The image separation time is 17 ms, and the total flow length is {approx} 10 cm. A circular eddy pattern that follows the slug can be readily seen and tracked, although reliability is low due to motion in the transverse direction. This motion also adds considerable error to the velocity measurements using image recognition technique. This will increase the reliability and accuracy of the tracking method.
FLOWTRAN-TF is a new two-component, two-phase thermal-hydraulics code to capture the detailed assembly behavior associated with loss-of-coolant accident analyses in multichannel assemblies of the SRS reactors. The local interfacial area of the two-phase mixture is computed by summing the interfacial areas contributed by each of three flow regimes. For smooth flow regime transitions, the code uses an interpolation technique in terms of component void fraction for each basic flow regime.
FLOWTRAN-TF is a new two-component, two-phase thermal-hydraulics code to capture the detailed assembly behavior associated with loss-of-coolant accident analyses in multichannel assemblies of the SRS reactors. The local interfacial area of the two-phase mixture is computed by summing the interfacial areas contributed by each of three flow regimes. For smooth flow regime transitions, the code uses an interpolation technique in terms of component void fraction for each basic flow regime.
Transverse glow discharges in supersonic air and methane flows are studied both experimentally and theoretically. The experiments show that a diffuse volume discharge filling the whole cross section of the flow can easily be initiated in air, whereas a diffuse discharge in a methane flow shows a tendency to transition into a constricted mode. The electron transport coefficients (mobility and drift velocity) and the kinetic coefficients (such as collisional excitation rates of the vibrational levels of a methane molecule, as well as dissociation and ionization rates) are calculated by numerically solving the Boltzmann equation for the electron energy distribution function. The calculated coefficients are used to estimate the parameters of the plasma and the electric field in the positive co...
;Contents: Comparison of Simulation Modules of TRANSYT and INTEGRATION Models; Evaluation of SCATSIM-RTA Adaptive Traffic Network Simulation Model; Comparison NETSIM, NETFLO I, and NETFLO II Traffic Simulation Models for Fixed-Time Signal Control; Traffic Flow Simulation Through Parallel Processing; Cluster Analysis as Tool in Traffic Engineering; Traffic Platoon Dispersion Modeling on Arterial Streets; Hybrid Model for Estimating Permitted Left-Turn Saturations Flow Rate; and Passing Sight Distance and Overtaking Dilemma on Two-Lane Roads.
comprehensive description for this model is available through AGARD, Reference [8]. ... Specifically, there is a pocket of flow separation at the side-of- body ...
Heat transfer and flow characteristics of water boiling flow were experimentally investigated in narrow horizontal rectangular channels with the gaps of 0.6mm-2.03mm. The heat transfer of two-phase boiling flow was weakend in smaller gap. The two-phase friction pressure drop decreased with the gap size and the two-phase friction multipliers were smaller compared with those in normal channels. Correlations to predict te boiling heat transfer coefficients were obtained. (author)
Focusing on Sobolev inequalities and their applications to analysis on manifolds and Ricci flow, "Sobolev Inequalities, Heat Kernels under Ricci Flow, and the Poincare Conjecture" introduces the field of analysis on Riemann manifolds and uses the tools of Sobolev imbedding and heat kernel estimates to study Ricci flows, especially with surgeries. The author explains key ideas, difficult proofs, and important applications in a succinct, accessible, and unified manner. The book first discusses Sobolev inequalities in various settings, including the Euclidean case, the Riemannian case,
Full text of publication follows: The heat transfer and flow in narrow channels has lots of advantages such as compact structure, high efficiency, design flexibility and so on. So it is widely used in the fields such as the new reactor core plate elements, the once-through stream generator, compact heat exchangers as well as electronic components. In recent years, more strong attentions have been attracted to the thermal-hydraulic characteristics and mechanism of the two-phase flow in narrow channels. As the flow regime characteristics of two-phase flow is fundamental one of them, the research on the two-phase flow regimes and the regime transitions in horizontal rectangular narrow heated channels can provide theoretical foundation and engineering directions to the whole research on the thermal-hydraulic characteristics and mechanism of the two-phase flow in ...
Full text of publication follows: The heat transfer and flow in narrow channels has lots of advantages such as compact structure, high efficiency, design flexibility and so on. So it is widely used in the fields such as the new reactor core plate elements, the once-through stream generator, compact heat exchangers as well as electronic components. In recent years, more strong attentions have been attracted to the thermal-hydraulic characteristics and mechanism of the two-phase flow in narrow channels. As the flow regime characteristics of two-phase flow is fundamental one of them, the research on the two-phase flow regimes and the regime transitions in horizontal rectangular narrow heated channels can provide theoretical foundation and engineering directions to the whole research on the thermal-hydraulic characteristics and mechanism of the two-phase flow in ...
... in tactics, techniques, and procedures (TTP), such as ... flow across the Afghanistan-Pakistan border, specifically ... The funds from the NATO ANA Trust ...
The report deals with: (1) two-phase flow regime transitions, (2) liquid entrainment in break flow, (3) vapor pull-through, and (4) CCFL in horizontal ducts. The first three processes influence the mass flow through the break, whereas the fourth one imposes a limit on liquid flow from the steam generator through the hot leg break into the core. Correlations available in the literature which deal with these processes are presented and applied to a hot leg of a PWR, LOFT and Semiscale for quantitative estimates, as well as for determining the scale distortion in the latter two facilities.
This paper discusses the influence of an endoscope on the peristaltic flow of a couple stress fluid in an annulus under a zero Reynolds number and long wavelength approximation. The inner tube is uniform, rigid, while the outer tube has a sinusoidal wave traveling down its wall. Analytical expressions for the axial velocity, stream function and axial pressure gradient are established. The flow is investigated in a wave frame of reference moving with the velocity of the wave. Numerical calculations are carried out for the pressure rise, frictional forces and trapping. The features of the flow characteristics are analyzed by plotting graphs and discussed in detail.
A flow field and particle trajectory in a HDD (Hard Disk Drive) between two rotating disks in axisymmetric enclosures is investigated using CFD code FLUENT/UNS. The RNG k-{epsilon} model is used as a turbulent model. In this study, the flow field between two disks are symmetric, and the flow field near the enclosure is very complex. Cross stream vectors are shown both for blowing and no blowing from the hub. The larger a particle, the more fast the particle deposits at the walls. In the case of blowing from the hub, the more fast the particle deposits at the walls. (author). 9 refs., 12 figs., 1 tab.
... They comprise of a power model for the representation of the electric system, a fluid model that represents the cooling fluid flow, three layers of ...
. This study investigates the geometric effects of 90-degree vertical elbows and flow configurations in two-phase flow. The study shows that the elbows make a significant effect on the transport characteristics of two-phase flow, which includes the changes in interfacial structures, bubble interaction mechanisms and flow regime transition. The effect of the elbows is characterized for global and local two-phase flow parameters. The global two-phase flow parameters include two-phase pressure, interfacial structures and flow regime transition. In order to characterize the frictional pressure drop and minor loss across the vertical elbows, pressure measurements are obtained across the test section over a wide range of flow conditions in both single-phase and two-phase flow conditions. A two-phase ...
Flow cytogenetics is a rapidly developing technology which complements rather than supplants the traditional methods of cytogenetic analysis. As an adjunctive approach to chromosome classification, flow systems measurements of isolated chromosomes give new information relative to the enrichment of A-T or G-C base sequences on specific chromosomes. As a result, chromosomal fluorescence polymorphisms both within and among individuals that are not always associated with banding polymorphisms can be detected. Finally, flow sorting provides bulk quantities of highly purified chromosomes for use in biochemical studies. Methodology is detailed. (PSB)
Group for Aerospace Research and Development (AGARD) symposium and continue to ...... of vertical structures and flow separation within the tip, platform, ...
CIRNAT, a one-dimensional code for natural circulation analysis, was described. The homogeneous approach was adopted for the two-phase flow regime and different heat transfer regimes were considered. The code was exhaustively tested for one-phase flow systems. For two phase flows a boiling/condensing system was simulated. The results are qualitatively correct but the oscillations observed at the system were not captured by the model. Other two-phase flow tests must be done to show the limits of the homogeneous approach before the introduction of a more complex model. (author)
CIRNAT, a one-dimensional code for natural circulation analysis, was described. The homogeneous approach was adopted for the two-phase flow regime and different heat transfer regimes were considered. The code was exhaustively tested for one-phase flow systems. For two phase flows a boiling/condensing system was simulated. The results are qualitatively correct but the oscillations observed at the system were not captured by the model. Other two-phase flow tests must be done to show the limits of the homogeneous approach before the introduction of a more complex model. (author)
When induced by bottom heating in a horizontal fluid layer which is characterized by forced motion or solute stratification, buoyancy-driven flows may assume a variety of forms. The flows, which are examples of mixed or double-diffusive convection, can strongly influence heat tranfer or the entrainment of stratified fluid. General aspects of each form of convection are reviewed, and emphasis is placed on mixed convection in a horizontal rectangular channel and on double-diffusive convection due to thermally driven mixed-layer development in a solutally stratified fluids. Flow conditions are described, and experimental and theoretical results are presented for related heat-transfer and entrainment parameters.
The Porous media approach method was applied to the MULTID component of MARS which was developed by KAERI. This method has been widely used for analysis of large regions containing only fluid and for flows in regions with immersed solids. It can calculate flow distribution more correctly in case of flow area or volume change. Application of this method to the MULTID component in MARS was evaluated and the results were compared with those of CFD code, FLUENT. As a result, the calculated flow distributions of MARS and FLUENT show similar trend, so the effect of porous media in MARS can be applied to the other cases.
The concentric circular annular duct is a common geometry in many fluid flow and heat transfer devices. For the purpose of heat transfer augmentation, fins are often employed in the annular region, and such finned ducts find wide application in compact heat exchangers (5, 6). The analysis of flow and heat transfer in this geometry is, therefore, quite important from an engineering standpoint. For fully developed conditions, the problem has already been analyzed (7-10). However, no results are available for the developing flow in the entrance region. It is with this latter problem that the present paper is concerned.
The advantages of using heads of around 1000 m in conjunction with underground location of the lower reservoirs for pumped storage plants are described, and the possible layouts, equipment, and construction methods are discussed.
BackgroundThe availability of multiple, essentially complete genome sequences of prokaryotes and eukaryotes spurred both the demand and the opportunity for the construction of an...Full Text Available
A floating boardwalk was constructed from the shore to ...... Irrespective of whether we could tie the outlier to a cause, a simple linear interpolation was ...
A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste.
A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste
This dissertation is devoted to the study of the phenomenological consequences of the three-generation heterotic string models based on the Calabi-Yau compactifications and the N = 2 superconformal constructions.
This paper described a risk control management tool that has been developed by Petrobras Petroleo, the largest Brazilian oil company and one of the world's leading oil companies. The system covers health, safety and environmental (HSE) issues regarding pipeline construction projects. The limitations of traditional safety management systems for coping with the critical problems related to environmental safety issues were discussed. In particular, this paper described how the HSE tool evaluates the risks resulting from the following aspects of onshore pipeline construction and assembly: establishing right-of-way and route locations, transporting pipe, developing the construction site, opening the trench, pipe laying, pipe bending, concrete external coating, welding, external anticorrosive coatings, pipe placement backfilling, hydrostatic testing, maintenance operations, and pipeline commissioning. 6 refs., 1 tab.
This paper describes the construction of PWR horizontal steam generator in Soviet Union, the water chemistry treatment for secondary side, the design of steam separator, the test of heat transfer characteristics and operation. (author).
Background: The nail gun is a commonly utilized tool in carpentry and construction. When used properly with appropriate safety precautions, it can facilitate production and boost efficiency;...Full Text Available
Since the elucidation of the structure of double helical DNA, the construction of small molecules that recognize and react at specific DNA sites has been an area of considerable interest. In...Full Text Available
Disclosed in this proposal are plans to construct a patent pending wrist module with computer control, configurable to form high-dexerity telerobotic arms ...
The goal of this effort Composability, Provability, Reusability (CPR) for Survivability is to address the problem of composition of survivable systems. The particular objective of this project is to construct a formal specification of the Java Virtual Mac...
Abstract The objective of this study was to investigate how a combination of different scaffold architectures and rotational culture would influence the functional properties of thick cartilaginous tissues engineered using either chondrocytes or bone marrow-derived mesenchymal stem cells (BM-MSCs). Expanded porcine chondrocytes and BM-MSCs were suspended in 2% agarose and cast in custom-designed moulds to produce either regular solid or channelled construct cylinders. The study consisted of three seperate experimental arms. First, chondrocyte and BM-MSC constructs were cultured in free swelling conditions for 9 weeks. Second, constructs were subjected to rotational culture for a period of 3 weeks. Finally, BM-MSC-seeded constructs were subjected to delayed rotational culture, in which cons...
Embracing the notion of going green, an affluent school district in Pennsylvania spent $83 million as part of the high school's renovation and expansion project. The three-level addition is now equipped with self-dimming lights, energy-efficient windows, a rooftop solar water heater, and a geothermal cooling and heating system. As a bonus for going green, the school district received a $250,000 grant from the Pennsylvania Department of Environmental Protection. The district used that money to create an information center in the lobby of the building where a touch-screen computer provides students, staff, and visitors with data related to the operation of the school's energy-efficient water and electrical systems. The system will graphically depict utility use over the course of a year. The monitoring system and touch-screen computer can turn this school into a living lab, with science, math, and economics teachers using the data as teaching tools within classrooms. Teachers can also ...
... in MEDCAP "the level of interface was left up ... of these patients had peripheral nerve injuries, head ... with poorly constructed prosthesis or waiting for ...
joint task force (JTF), division (OIV) and regimental combat team (RCT) with ..... Headquarters, Department of the Army. (HQOA), (2010). Field Manual 2-0 ...
A transient flow reduction burnout experiment was conducted with water in a uniformly heated, vertically oriented tube. Test pressures ranged from 0.5 to 3.9 MPa. An analytical method was developed to obtain transient burnout conditions at the exit. A simple correlation to predict the deviation of the transient burnout mass velocity at the tube exit from the steady state mass velocity obtained as a function of steam-water density ratio and flow reduction rate. The correlation was also compared with the other data. (author).
We proposed a solid and a mercury target concepts through the preliminary conceptual design. To feasible these concepts, analysis and experimental works are being carried out. This paper introduces an outline of present status of target R and D such as heat transfer augmentation experiments for the solid target, mercury flow tests with a loop of maximum flow rate of 15L/min, flow pattern measurements for a cold source moderator etc. as well as preliminary conceptual design works. (author)
Parameters of the vortex air flow in an isothermal model of the cyclone chamber are studied. The effect of the air velocity in nozzles on the values and character of the distribution of pressure and tangential and longitudinal velocities of air in the chamber is determined. Numerical modeling of the flow is performed, and it is shown that numerical calculation by the k-w turbulence model is in agreement with experimental data.
The developments of fields in deep waters (5000 ft and more) is a common occurrence. It is inevitable that production systems will operate under multiphase flow conditions (simultaneous flow of gas-oil-and water possibly along with sand, hydrates, and wax...
The effects of non-Darcy flow laws are investigated for two geothermal reservoir types: multiphase and Hot Dry Rock (HDR). Long-term thermal behavior is emphasized as short-term pressure transient behavior is addressed in the oil field literature. Comparisons of Darcy and non-Darcy flow laws are made.
An experimental study was undertaken to determine for the turbulent regime the heat transfer and fluid flow characteristics of a heat exchange array of unperforated, and perforated brass plates with 33% of the plate area open. In both cases, the plates were aligned parallel to the flow direction. For the flow conditions examined, the results showed enhancement of heat transfer and friction factor for the perforated array.
This book presents the papers given at a conference on two-phase flow. Topics considered at the conference included the thermal hydraulics of a feedwater pipe breakage, pressure losses, measurement of void fraction in a rod bundle, laminar filmwise condensation, natural circulation, flow models, bubble dynamics, cavitation, water hammer, and heat transfer augmentation.
This book presents the papers given at a conference on two-phase flow. Topics considered at the conference included the thermal hydraulics of a feedwater pipe breakage, pressure losses, measurement of void fraction in a rod bundle, laminar filmwise condensation, natural circulation, flow models, bubble dynamics, cavitation, water hammer, and heat transfer augmentation.
Unsymmetric diaryl alkynes were synthesized from the palladium-catalyzed decarboxylative coupling of aryl halides and propiolic acid using a continuous flow reaction system. This flow chemistry system continuously gave the desired products in moderate to good yields, and produced less byproduct than was formed in the batch reaction.
Isotopically selective IR multiphoton dissociation of molecules (SF_6, CF_3I) in a pulsed gas-dynamic flow interacting with a solid surface was studied for the first time. A noticeable (severalfold) increase in the yield of products (compared to excitation of molecules in an unperturbed flow) without a substantial decrease in the selectivity of the process was observed. Possible reasons for the effect are discussed. (laser applications and other topics in quantum electronics)
Whereas linear electron flow (LEF) in photosynthesis produces both ATP and NADPH, the cyclic electron flow (CEF) around photosystem I has been shown to produce only ATP. Two alternative routes have...Full Text Available
The developments of oil and gas fields in deep waters (5000 ft and more) will become more common in the future. It is inevitable that production systems will operate under multiphase flow conditions (simultaneous flow of gas-oiland water possibly along wi...
The purpose of this thesis is to study the behaviour of the simultaneous flow of oil and water in horizontal pipes. In this connection, two test facilities are used. Both facilities have horizontal test sections with inner pipe diameters equal to 2 inches. The largest facility, called the model oil facility, has reservoirs of 1 m{sub 3} of each medium enabling flow rates as high as 30 m{sub 3}/h, which corresponds to mixture velocities as high as 3.35 m/s. The flow rates of oil and water can be varied individually producing different flow patterns according to variations in mixture velocity and input water cut. Two main classes of flows are seen, stratified and dispersed. In this facility, the main focus has been on stratified flows. Pressure drops and local phase fractions are measured for a large number of flow conditions. Among the ...
The behavior of air flows in complex heat exchanger passages is reviewed with a focus on the heat transfer effects of boundary-layer development, turbulence, spanwise and streamwise vortices, and wake management. Each of these flow features is discussed for the plain, wavy, and interrupted passages found in contemporary compact heat exchanger designs. Results from the literature are used to help explain the role of these mechanisms in heat transfer enhancement strategies.
This book contains nine selections. Some of the titles are: High Heat-Flux, Forced-Convection Heat Transfer for Tubes with Twisted-Tape Inserts; Heat Transfer Augmentation by Interrupted Surfaces - Experimental Consideration; Turbulent Flow Heat Transfer from Externally Roughened Tubes in Axial Flow in Concentric Pipe Heat Exchangers; and Heat Transfer Enhancement of Turbulent Flow in Pipes with an Internal Circular Rib.
This book contains nine selections. Some of the titles are: High Heat-Flux, Forced-Convection Heat Transfer for Tubes with Twisted-Tape Inserts; Heat Transfer Augmentation by Interrupted Surfaces - Experimental Consideration; Turbulent Flow Heat Transfer from Externally Roughened Tubes in Axial Flow in Concentric Pipe Heat Exchangers; and Heat Transfer Enhancement of Turbulent Flow in Pipes with an Internal Circular Rib.