The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Suizheng Qiu - One of the best experts on this subject based on the ideXlab platform.
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CFD simulation of secondary Side Fluid flow and heat transfer of the passive residual heat removal heat exchanger
Nuclear Engineering and Design, 2018Co-Authors: Wenxi Tian, Suizheng QiuAbstract:Abstract Passive residual heat removal heat exchanger (PRHR HX) is a key equipment in advanced passive safety pressurized water reactors (PWRs), such as AP1000. Immerged in the In-containment refueling water storage tank (IRWST), the C-shape PRHR HX removes the residual heat using natural convection and boiling heat transfer during postulated accidents. Therefore, the safety operation of the PRHR HX is very important for the nuclear power plant (NPP). In this paper, three dimensional CFD simulation of the secondary Side Fluid flow and heat transfer of the PRHR HX is performed. The drift flux model is used to simulate the two phase flow phenomenon in the IRWST. The tube region is modeled by the porous media approach. The flow resistance in the tube region is calculated by empirical pressure drop correlation and two phase flow multiplier. The heat transfer rate from the primary Side to the secondary Side Fluid is also evaluated by widely used heat transfer empirical correlations. Additional source terms corresponding to the flow resistance and removed heat in the tube region are added to the momentum and energy equation, respectively. The governing equations are solved by the commercial CFD package FLUENT. Three dimensional distributions of the Fluid velocity, temperature and void fraction are obtained. The heat transfer characteristics of the tube bundle is analyzed.
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CFD investigation on thermal hydraulics of the passive residual heat removal heat exchanger (PRHR HX)
Nuclear Engineering and Design, 2018Co-Authors: Wenxi Tian, Suizheng QiuAbstract:Abstract Passive residual heat removal (PRHR) system is a very important component of the passive safety systems in advanced passive safety pressurizer water reactors (PWRs) such as AP1000. The passive residual heat removal heat exchanger (PRHR HX) is a C-shape tube bundle heat exchanger immerged in the In-containment refueling water storage tank (IRWST) which removes the core decay heat during the accident transients. The performance of the PRHR HX is significant for the safety of the nuclear power plant (NPP). In this paper, the thermal hydraulics characteristics of the PRHR HX in the IRWST is analyzed using computational Fluid dynamics (CFD). The tube region is modeled by the porous media approach along with the distributed resistance method. Heat transfer from the primary Side Fluid inSide the tube to the secondary Side Fluid in the IRWST is conSidered. The simulation is carried out by the commercial CFD package FLUENT. The calculation of the flow resistance and heat transfer in the tube region is implemented using the User Defined Functions (UDF) in FLUENT based on the local flow conditions. Three dimensional distributions of the Fluid velocity and temperature in the IRWST are obtained and thermal stratification is observed. The PRHR HX heat transfer capacity and the primary Side Fluid temperature distribution inSide tubes are analyzed.
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Effects of power level on thermal-hydraulic characteristics of steam generator
Progress in Nuclear Energy, 2015Co-Authors: Tenglong Cong, Rui Zhang, Wenxi Tian, Suizheng QiuAbstract:Abstract The thermohydraulics of the steam generator secondary is analyzed using Fluent's porous media model coupled to a two-phase flow mixture model. The resistances introduced by the tubes, supports, downcomers and separators are calculated as the source terms of the momentum equation. The heat transfer from primary Side Fluid to the secondary is calculated three-dimensionally each iteration and is supplied as a heat source on the secondary flow field calculation. The effects of the power level on thermal hydraulic characteristics in the steam generator are also investigated. Flow-induced vibration damage increased in severity with increasing power level.
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Numerical Investigation on Heat Removal Capacity of Passive Residual Heat Removal Heat Exchanger
Volume 4: Radiation Protection and Nuclear Technology Applications; Fuel Cycle Radioactive Waste Management and Decommissioning; Computational Fluid D, 2014Co-Authors: Wenwen Zhang, Wenxi Tian, Suizheng QiuAbstract:In the present study, thermal-hydraulics characteristics of AP1000 passive residual heat removal heat exchanger (PRHR-HX) at initial operating stage were analyzed based on the porous media models. The data predicated by RELAP5 under the condition of the station blackout was employed as the inlet flow rate and temperature boundary of CFD calculation. The heat transfer from the primary Side coolant to the in-containment refueling water storage tank (IRWST) Side Fluid was calculated in a three-dimensional geometry during iterations, and the distributed resistances were added into the C-type tube bundle regions. Three-dimensional distributions of velocity and temperature in the IRWST were calculated by the CFD code ANSYS FLUENT. The primary temperature, heat transfer coefficients of two Sides and the heat transfer were obtained using the coupled heat transfer between the primary Side and the IRWST Side. The simulation results indicated that the water temperature rises gradually which leads to a thermal stratification phenomenon in the tank and the heat transfer capability decreases with an increase of water temperature. The present results indicated that the method containing coupled heat transfer from the primary Side Fluid to IRWST Side Fluid and porous media model is a suitable approach to study the transient thermal-hydraulics of PRHR/IRWST system.© 2014 ASME
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Three-dimensional study on steady thermohydraulics characteristics in secondary Side of steam generator
Progress in Nuclear Energy, 2014Co-Authors: Tenglong Cong, Suizheng Qiu, Tian Wenxi, Yongcheng Xie, Yangui YaoAbstract:Abstract Steam generator (SG), as the primary-to-secondary heat exchanger and pressure boundary of primary loop, should be integrated and perform well in heat transfer ability. Flow characteristics of the secondary Side Fluid of SG are essential to analyze U-tube wastage caused by the flow-induced vibration and thermal stress. In this paper, secondary Side two-phase flow was simulated based on the porous media model. Additional momentum and energy source terms were appended to the momentum and energy equations for porous media region, respectively. The additional momentum source contained the resistances of downcomer, tube bundle, support plate and separator. The additional energy source included the heat transfer from primary Side to secondary Side Fluid. Solving the governing equations by ANSYS FLUENT solver yielded the distributions of velocity, temperature, pressure, density and quality, which can be used in the analysis of flow-induced vibration and separators. The thermal-hydraulic characteristics of hot Side differed from these of cold Side conSiderably. The minimum flow quality of cold Side was 0.07, while the maximum one of hot Side was 0.71; the average flow quality of outlet was 0.272. The flow rate in the gap of the hot Side was 1.02 times of that of the cold Side.
A. Venu Vinod - One of the best experts on this subject based on the ideXlab platform.
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Natural convection heat transfer using water-based nanoFluid in a shell and helical coil heat exchanger
Chemical Papers, 2021Co-Authors: Tangellapalli Srinivas, A. Venu VinodAbstract:Industry is looking for more efficient ways to use nanomaterials to decrease water consumption. The addition of greater thermal conductivity nanoparticles to the water enhances the Fluid's thermal conductivity and, thus, increases the coefficient of heat transfer. In this work, water-based nanoFluids were used to perform heat transfer enhancement studies in a shell and helical coil heat exchanger. Natural convection heat transfer using three water-based nanoFluids (Al_2O_3, CuO and TiO_2/water) was investigated in shell and helical coil heat exchanger. Experiments were performed at different hot water flow rates through coil (Dean number) and hot water feed temperatures (40, 50 and 60 °C). The use of water-based nanoFluid led in a greater coefficient of shell-Side heat transfer compared to the use of pure water on the shell Side. The Nusselt number improved due to an increase in nanoparticle concentration. It was observed that with a rise in nanoFluid concentration, Dean number and greater coil-Side Fluid feed temperature, the Rayleigh number increased.
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Heat transfer enhancement using non-Newtonian nanoFluids in a shell and helical coil heat exchanger
Experimental Thermal and Fluid Science, 2018Co-Authors: B. Anil Kumar Naik, A. Venu VinodAbstract:Abstract The current investigation examines heat transfer using three different non-Newtonian nanoFluids comprising of Fe 2 O 3 , Al 2 O 3 and CuO nanoparticles in aqueous carboxymethyl cellulose (CMC) base Fluid. The studies were carried out to determine enhancement in heat transfer compared to base Fluid (aqueous CMC solution) in a shell and helical coil heat exchanger. Non-Newtonian nanoFluids containing nanoparticles in the concentration range of 0.2–1.0 wt% were prepared. NanoFluid and water were used on shell Side and tube Side respectively. The thermal analysis was carried out to determine overall heat transfer coefficient and shell-Side Nusselt number, at different conditions such as flow rate of cold water (0.5–5 lpm), shell Side Fluid (nanoFluid) temperature (40–60 °C) and stirrer speeds (500–1500 rpm). The results show that the Nusselt number increases with increasing nanoFluid concentration, shell Side Fluid temperature, Dean number (flow rate of coil-Side water), and stirrer speeds. It was found that the CuO/CMC-based nanoFluid showed better heat transfer than the other two types of Fluid (Fe 2 O 3 and Al 2 O 3 ). The heat transfer performance of non-Newtonian nanoFluids was significantly enhanced at higher nanoFluid concentrations, shell-Side temperatures, stirrer speeds and Dean numbers.
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Heat transfer intensification in a shell and helical coil heat exchanger using water-based nanoFluids
Chemical Engineering and Processing: Process Intensification, 2016Co-Authors: Tangellapalli Srinivas, A. Venu VinodAbstract:Abstract NanoFluids have been reported to be capable of heat transfer intensification. Performance of an agitated shell and helical coil heat exchanger has been experimentally investigated using three water based nanoFluids (Al 2 O 3 , CuO and TiO 2 ). The studies were carried out at different concentrations of nanoFluid, nanoFluid temperatures, stirrer speeds and coil-Side Fluid flow rates. NanoFluids of three concentrations 0.3, 0.6, 1, 1.5 and 2% by weight have been prepared for this purpose. Cetyltrimethyl ammonium bromide (CTAB) was used as stabilizer. NanoFluid was used as heating medium (shell-Side) and water was used as coil-Side Fluid. It was found that heat transfer rate increases with increase in nanoFluid concentration. Higher values of nanoFluid concentration, stirrer speed and shell-Side Fluid temperature resulted in greater effectiveness of heat exchanger. A maximum increase of 30.37%, 32.7% and 26.8% in effectiveness of heat exchanger was observed for Al 2 O 3 , CuO and TiO 2 /water nanoFluids respectively, when compared to water, indicating intensification of heat transfer.
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Heat Transfer Enhancement using CuO / Water NanoFluid in a Shell and Helical Coil Heat Exchanger
Procedia Engineering, 2015Co-Authors: Tangellapalli Srinivas, A. Venu VinodAbstract:Forced convective heat transfer studies have been carried out in an agitated shell and helical coil heat exchanger using CuO/water nanoFluid. Experiments have been carried out in a shell and helical coil heat exchanger at various concentrations of CuO nanoparticles in water (0.3, 0.6, 1, 1.5 and 2% wt.), stirrer speeds (500, 1000 and 1500 rpm) and shell-Side Fluid (heating medium) temperatures (40, 45 and 50oC). Water has been used as coil-Side Fluid, and studies have been conducted at different values of Dean number (flow rates). Enhancement in heat transfer due to the use of nanoFluid has been reported in terms of heat transfer rate.
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Performance of an agitated helical coil heat exchanger using Al2O3/water nanoFluid
Experimental Thermal and Fluid Science, 2013Co-Authors: Tangellapalli Srinivas, A. Venu VinodAbstract:Abstract The performance of an agitated helical coil heat exchanger using Al 2 O 3 /water nanoFluid has been evaluated in terms of the energy consumed to heat another Fluid. The comparison has been made when nanoFluid and base Fluid (water) are used as heating medium. The studies have been carried out using Al 2 O 3 /water nanoFluid of different concentrations, flow rates, stirrer speeds and shell-Side Fluid (heating medium) temperatures. It has been observed that, energy savings are more in laminar and turbulent conditions of flow than transition regime, and percentage savings increase with increase in nanoparticle concentration. Higher stirrer speed and shell-Side Fluid temperature also resulted in more energy savings. In addition, use of nanoFluid resulted in heating the coil-Side Fluid (water) to higher outlet temperature. Maximum energy savings of 10.65% have been obtained in the presentstudy.
Tenglong Cong - One of the best experts on this subject based on the ideXlab platform.
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analysis of westinghouse mb2 test using the steam generator thermohydraulics analysis code staf
Annals of Nuclear Energy, 2015Co-Authors: Tenglong Cong, Rui ZhangAbstract:Abstract In the present study, we develop a Steam-generator Thermohydraulics Analysis code based on Fluent (STAF) for predicting the three-dimensional localized thermal–hydraulic characteristics in the primary and secondary Sides of steam generator. STAF code is developed based on the porous media model in Fluent. The flow resistances caused by the tubes, support plates, downcomer and separators are introduced to the momentum equation as additional source terms of shell Side Fluid; the heat transfer from primary to secondary Side Fluid is conSidered as the source term of energy equation of secondary Side Fluid. The flow and heat transfer in primary Side, as well as the tube-to-shell-Side heat transfer are solved by the user-defined functions in Fluent. STAF is used to simulate the Westinghouse MB2 test, and localized thermohydraulics parameters are obtained. The numerical results show good agreement with experimental results, demonstrating the ability of STAF to model the three-dimensional flow and heat transfer characteristics in primary and secondary Side of steam generator. BeSides, parameters associated with flow-induced vibration are also analyzed.
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Effects of power level on thermal-hydraulic characteristics of steam generator
Progress in Nuclear Energy, 2015Co-Authors: Tenglong Cong, Rui Zhang, Wenxi Tian, Suizheng QiuAbstract:Abstract The thermohydraulics of the steam generator secondary is analyzed using Fluent's porous media model coupled to a two-phase flow mixture model. The resistances introduced by the tubes, supports, downcomers and separators are calculated as the source terms of the momentum equation. The heat transfer from primary Side Fluid to the secondary is calculated three-dimensionally each iteration and is supplied as a heat source on the secondary flow field calculation. The effects of the power level on thermal hydraulic characteristics in the steam generator are also investigated. Flow-induced vibration damage increased in severity with increasing power level.
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Three-dimensional study on steady thermohydraulics characteristics in secondary Side of steam generator
Progress in Nuclear Energy, 2014Co-Authors: Tenglong Cong, Suizheng Qiu, Tian Wenxi, Yongcheng Xie, Yangui YaoAbstract:Abstract Steam generator (SG), as the primary-to-secondary heat exchanger and pressure boundary of primary loop, should be integrated and perform well in heat transfer ability. Flow characteristics of the secondary Side Fluid of SG are essential to analyze U-tube wastage caused by the flow-induced vibration and thermal stress. In this paper, secondary Side two-phase flow was simulated based on the porous media model. Additional momentum and energy source terms were appended to the momentum and energy equations for porous media region, respectively. The additional momentum source contained the resistances of downcomer, tube bundle, support plate and separator. The additional energy source included the heat transfer from primary Side to secondary Side Fluid. Solving the governing equations by ANSYS FLUENT solver yielded the distributions of velocity, temperature, pressure, density and quality, which can be used in the analysis of flow-induced vibration and separators. The thermal-hydraulic characteristics of hot Side differed from these of cold Side conSiderably. The minimum flow quality of cold Side was 0.07, while the maximum one of hot Side was 0.71; the average flow quality of outlet was 0.272. The flow rate in the gap of the hot Side was 1.02 times of that of the cold Side.
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Three-Dimensional Steady Simulation on Two-Phase Flow in Secondary Side of Steam Generator
Volume 6: Beyond Design Basis Events; Student Paper Competition, 2013Co-Authors: Tenglong Cong, Wenxi Tian, Suizheng QiuAbstract:Steam generator (SG), as the primary-to-secondary heat exchanger and pressure boundary of primary loop, should be integrated and performs well in heat transfer ability. Flow characteristics of the secondary Side Fluid of SG are essential to analyze U-tube wastage caused by the flow-induced vibration and thermal stress. In this paper, secondary Side two-phase flow was simulated based on the porous media model. Additional momentum and energy source terms were appended to the momentum and energy equations of porous media region, respectively. The additional momentum source contained the resistances of downcomer, tube bundle, support plate and separator. The additional energy source included the heat transfer from primary Side to secondary Side Fluid. Solving the control equations by ANSYS FLUENT solver yielded the distributions of velocity, temperature, pressure, density and quality, which can be used in the analysis of flow-induced vibration and separator.Copyright © 2013 by ASME
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Study on secondary Side flow of steam generator with coupled heat transfer from primary to secondary Side
Applied Thermal Engineering, 2013Co-Authors: Tenglong Cong, Tian Wenxi, Suizheng QiuAbstract:Abstract Thermohydraulics characteristics in the secondary Side of AP1000 steam generator (SG) are simulated based on the porous media models. The drift flux two-phase flow model coupled with a simplified flow boiling model is utilized. The heat transfer from primary Side Fluid to secondary Side Fluid is calculated three-dimensionally during iterations. The resistances caused by downcomer, tube bundle, support plates and primary separators are conSidered. Three-dimensional distributions of velocity, temperature, pressure, enthalpy, density, void fraction and flow vapor quality are obtained from the calculation by using the CFD code ANSYS FLUENT. Flow-induced vibration (FIV) damage is analyzed based on the cross flow velocity over the U-bend region of the outmost U-tube. The most severe FIV damages occur at the angles of −0.544 rad on the cold Side and 0.353 rad on the hot Side with maximum cross flow energies of 1145.2 J/m3 and 658.9 J/m3, respectively. Fouling is expected to deposit at the bottom of tube bundle since the velocity there is close to zero. The flow vapor qualities of mixture flowing into separators vary from each other significantly, with the maximum and minimum flow vapor quality in separators of 0.659 and 0.073, which is a severe challenge to the capacity design of separators.
Tangellapalli Srinivas - One of the best experts on this subject based on the ideXlab platform.
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Natural convection heat transfer using water-based nanoFluid in a shell and helical coil heat exchanger
Chemical Papers, 2021Co-Authors: Tangellapalli Srinivas, A. Venu VinodAbstract:Industry is looking for more efficient ways to use nanomaterials to decrease water consumption. The addition of greater thermal conductivity nanoparticles to the water enhances the Fluid's thermal conductivity and, thus, increases the coefficient of heat transfer. In this work, water-based nanoFluids were used to perform heat transfer enhancement studies in a shell and helical coil heat exchanger. Natural convection heat transfer using three water-based nanoFluids (Al_2O_3, CuO and TiO_2/water) was investigated in shell and helical coil heat exchanger. Experiments were performed at different hot water flow rates through coil (Dean number) and hot water feed temperatures (40, 50 and 60 °C). The use of water-based nanoFluid led in a greater coefficient of shell-Side heat transfer compared to the use of pure water on the shell Side. The Nusselt number improved due to an increase in nanoparticle concentration. It was observed that with a rise in nanoFluid concentration, Dean number and greater coil-Side Fluid feed temperature, the Rayleigh number increased.
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Heat transfer intensification in a shell and helical coil heat exchanger using water-based nanoFluids
Chemical Engineering and Processing: Process Intensification, 2016Co-Authors: Tangellapalli Srinivas, A. Venu VinodAbstract:Abstract NanoFluids have been reported to be capable of heat transfer intensification. Performance of an agitated shell and helical coil heat exchanger has been experimentally investigated using three water based nanoFluids (Al 2 O 3 , CuO and TiO 2 ). The studies were carried out at different concentrations of nanoFluid, nanoFluid temperatures, stirrer speeds and coil-Side Fluid flow rates. NanoFluids of three concentrations 0.3, 0.6, 1, 1.5 and 2% by weight have been prepared for this purpose. Cetyltrimethyl ammonium bromide (CTAB) was used as stabilizer. NanoFluid was used as heating medium (shell-Side) and water was used as coil-Side Fluid. It was found that heat transfer rate increases with increase in nanoFluid concentration. Higher values of nanoFluid concentration, stirrer speed and shell-Side Fluid temperature resulted in greater effectiveness of heat exchanger. A maximum increase of 30.37%, 32.7% and 26.8% in effectiveness of heat exchanger was observed for Al 2 O 3 , CuO and TiO 2 /water nanoFluids respectively, when compared to water, indicating intensification of heat transfer.
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Heat Transfer Enhancement using CuO / Water NanoFluid in a Shell and Helical Coil Heat Exchanger
Procedia Engineering, 2015Co-Authors: Tangellapalli Srinivas, A. Venu VinodAbstract:Forced convective heat transfer studies have been carried out in an agitated shell and helical coil heat exchanger using CuO/water nanoFluid. Experiments have been carried out in a shell and helical coil heat exchanger at various concentrations of CuO nanoparticles in water (0.3, 0.6, 1, 1.5 and 2% wt.), stirrer speeds (500, 1000 and 1500 rpm) and shell-Side Fluid (heating medium) temperatures (40, 45 and 50oC). Water has been used as coil-Side Fluid, and studies have been conducted at different values of Dean number (flow rates). Enhancement in heat transfer due to the use of nanoFluid has been reported in terms of heat transfer rate.
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Performance of an agitated helical coil heat exchanger using Al2O3/water nanoFluid
Experimental Thermal and Fluid Science, 2013Co-Authors: Tangellapalli Srinivas, A. Venu VinodAbstract:Abstract The performance of an agitated helical coil heat exchanger using Al 2 O 3 /water nanoFluid has been evaluated in terms of the energy consumed to heat another Fluid. The comparison has been made when nanoFluid and base Fluid (water) are used as heating medium. The studies have been carried out using Al 2 O 3 /water nanoFluid of different concentrations, flow rates, stirrer speeds and shell-Side Fluid (heating medium) temperatures. It has been observed that, energy savings are more in laminar and turbulent conditions of flow than transition regime, and percentage savings increase with increase in nanoparticle concentration. Higher stirrer speed and shell-Side Fluid temperature also resulted in more energy savings. In addition, use of nanoFluid resulted in heating the coil-Side Fluid (water) to higher outlet temperature. Maximum energy savings of 10.65% have been obtained in the presentstudy.
Yangui Yao - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional study on steady thermohydraulics characteristics in secondary Side of steam generator
Progress in Nuclear Energy, 2014Co-Authors: Tenglong Cong, Suizheng Qiu, Tian Wenxi, Yongcheng Xie, Yangui YaoAbstract:Abstract Steam generator (SG), as the primary-to-secondary heat exchanger and pressure boundary of primary loop, should be integrated and perform well in heat transfer ability. Flow characteristics of the secondary Side Fluid of SG are essential to analyze U-tube wastage caused by the flow-induced vibration and thermal stress. In this paper, secondary Side two-phase flow was simulated based on the porous media model. Additional momentum and energy source terms were appended to the momentum and energy equations for porous media region, respectively. The additional momentum source contained the resistances of downcomer, tube bundle, support plate and separator. The additional energy source included the heat transfer from primary Side to secondary Side Fluid. Solving the governing equations by ANSYS FLUENT solver yielded the distributions of velocity, temperature, pressure, density and quality, which can be used in the analysis of flow-induced vibration and separators. The thermal-hydraulic characteristics of hot Side differed from these of cold Side conSiderably. The minimum flow quality of cold Side was 0.07, while the maximum one of hot Side was 0.71; the average flow quality of outlet was 0.272. The flow rate in the gap of the hot Side was 1.02 times of that of the cold Side.