J. Cotton, Jen-Shih Chang, M. Shoukri, T. Smith-Pollard
In order to explore the mechanics of EHD induced flow and heat transfer augmentation, an experimental study of the tube-side boiling heat transfer of refrigerant HFC-134a has been conducted in a single-pass, counter-flow heat exchanger. The electrode position was arranged concentric to the tube. Experiments are conducted for inlet qualities of 0% to 60%, mass fluxes from 100 kg/m2s to 500 kg/m2s, heat fluxes of 10 kW/m2 and 20 kW/m2, and applied voltage from 0 kV to 8 kV DC. The threshold of EHD effects were analysed by a proposed dimensional analysis which predicts that the EHD forces become significant when the Dielectric Electric Rayleigh number is of the same order of magnitude as the square of the liquid Reynolds number, Eℓε ≈ Re ℓ 2 . This criterion is supported by experimental evidence. Flow visualization experiments have shown that, when the proposed dimensionless criterion is satisfied, EHD body forces may have a strong influence on the liquid-phase and consequently the flow pattern within the channel. The various flow configurations clearly affect heat transfer and pressure loss and need to be considered in any attempt to identify the effects of an applied electric field.
{"title":"Electrohydrodynamic (EHD) Flow and Convective Boiling Augmentation in Single-Component Horizontal Annular Channels","authors":"J. Cotton, Jen-Shih Chang, M. Shoukri, T. Smith-Pollard","doi":"10.1115/imece2000-1519","DOIUrl":"https://doi.org/10.1115/imece2000-1519","url":null,"abstract":"\u0000 In order to explore the mechanics of EHD induced flow and heat transfer augmentation, an experimental study of the tube-side boiling heat transfer of refrigerant HFC-134a has been conducted in a single-pass, counter-flow heat exchanger. The electrode position was arranged concentric to the tube. Experiments are conducted for inlet qualities of 0% to 60%, mass fluxes from 100 kg/m2s to 500 kg/m2s, heat fluxes of 10 kW/m2 and 20 kW/m2, and applied voltage from 0 kV to 8 kV DC. The threshold of EHD effects were analysed by a proposed dimensional analysis which predicts that the EHD forces become significant when the Dielectric Electric Rayleigh number is of the same order of magnitude as the square of the liquid Reynolds number, Eℓε ≈ Re ℓ 2 . This criterion is supported by experimental evidence. Flow visualization experiments have shown that, when the proposed dimensionless criterion is satisfied, EHD body forces may have a strong influence on the liquid-phase and consequently the flow pattern within the channel. The various flow configurations clearly affect heat transfer and pressure loss and need to be considered in any attempt to identify the effects of an applied electric field.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124092545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Mcassey, Jinfeng Wu, T. Dougherty, Bao Wen Yang
Data are presented for sub-cooled boiling of water in the range of two to four atmospheres. The results show that the sharp increase in heat transfer coefficient associated with nucleate boiling occurs at wall superheats of 20 °C to 30 °C. Comparisons between experimental and predicted heat transfer coefficients are also presented. The two prediction methods examined are the Chen correlation and the Kandlikar correlation.
{"title":"Prediction of Heat Transfer Coefficients Under Sub-Cooled Boiling Conditions","authors":"E. Mcassey, Jinfeng Wu, T. Dougherty, Bao Wen Yang","doi":"10.1115/imece2000-1501","DOIUrl":"https://doi.org/10.1115/imece2000-1501","url":null,"abstract":"\u0000 Data are presented for sub-cooled boiling of water in the range of two to four atmospheres. The results show that the sharp increase in heat transfer coefficient associated with nucleate boiling occurs at wall superheats of 20 °C to 30 °C. Comparisons between experimental and predicted heat transfer coefficients are also presented. The two prediction methods examined are the Chen correlation and the Kandlikar correlation.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123230713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An experimental investigation of two-phase flow mechanisms during condensation of refrigerant R134a in small diameter round and rectangular tubes was conducted. A 4.91 mm round tube, and four round tubes with hydraulic diameters ranging from 1 mm – 4 mm were studied to characterize the influence of tube miniaturization on the flow mechanisms. For each tube under consideration, flow mechanisms were recorded over the entire range of qualities 0 < x < 1, and for five different mass fluxes between 150 kg/m2-s and 750 kg/m2-s. Approximately 50 data points were recorded for each tube to obtain a comprehensive understanding of the effects of geometry, mass flux and quality on the phase-change flow mechanisms. The flow mechanisms were categorized into four different flow regimes: intermittent flow, wavy flow, annular flow, and dispersed flow. In addition, the large amount of data over a wide range of test conditions enabled the delineation of several different flow patterns within each flow regime, which provides a clearer understanding of the different modes of two-phase flow. Transition lines between the respective flow patterns and regimes on these maps were established based on the experimental data. It was found that the intermittent flow regime becomes larger as the tube hydraulic diameter is decreased. Also, the size of the wavy flow regime decreases for the small diameter tubes, and disappears completely for the 1 × 1 mm square tube. These maps and transition lines can be used to predict the flow pattern or regime that will be established for a given mass flux, quality and tube geometry.
{"title":"Two-Phase Flow Regime Transitions in Microchannel Tubes: The Effect of Hydraulic Diameter","authors":"J. Coleman, S. Garimella","doi":"10.1115/imece2000-1508","DOIUrl":"https://doi.org/10.1115/imece2000-1508","url":null,"abstract":"\u0000 An experimental investigation of two-phase flow mechanisms during condensation of refrigerant R134a in small diameter round and rectangular tubes was conducted. A 4.91 mm round tube, and four round tubes with hydraulic diameters ranging from 1 mm – 4 mm were studied to characterize the influence of tube miniaturization on the flow mechanisms. For each tube under consideration, flow mechanisms were recorded over the entire range of qualities 0 < x < 1, and for five different mass fluxes between 150 kg/m2-s and 750 kg/m2-s. Approximately 50 data points were recorded for each tube to obtain a comprehensive understanding of the effects of geometry, mass flux and quality on the phase-change flow mechanisms. The flow mechanisms were categorized into four different flow regimes: intermittent flow, wavy flow, annular flow, and dispersed flow. In addition, the large amount of data over a wide range of test conditions enabled the delineation of several different flow patterns within each flow regime, which provides a clearer understanding of the different modes of two-phase flow. Transition lines between the respective flow patterns and regimes on these maps were established based on the experimental data. It was found that the intermittent flow regime becomes larger as the tube hydraulic diameter is decreased. Also, the size of the wavy flow regime decreases for the small diameter tubes, and disappears completely for the 1 × 1 mm square tube. These maps and transition lines can be used to predict the flow pattern or regime that will be established for a given mass flux, quality and tube geometry.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132314907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. E. Jih, K. Chen, T. Abraham, V. Siddapureddy, R. Poulson, V. A. Sankaran
As the performance of the advanced electric systems increases, the packaging densities and power requirements will also increase. The reliability of these components will depend on the ability of the packaging system to transport heat away from the device. In this paper, a liquid-cooled coldplate for the inverter of hybrid electric vehicle was designed by using Computational Fluid Dynamics (CFD) technique. The main features of inverter packaging include power module, capacitors, busbar, gate driver, gate power supply, coldplate, sensors, & controllers. How to effectively dissipate the heat from power module to the coldplate is the focus of this study. The 3-phase full bridge power module consists of 12 IGBTs and 12 diodes. The silicon dies of IGBT or diode were soldered to the direct-bonded ceramic (DBC) A1N substrate, and to the copper base plate. Then the whole module was mounted mechanically onto an aluminum coldplate using thermal grease at the interface. The maximum allowable die junction temperature is 125°C. The commercial CFD code, FLUENT, was used here to study the flow field and heat transfer of the coldplate. In order to have confidence in the CFD prediction, the temperature distribution of an inverter assembly was obtained from FLUENT and then verified with the measurement from an infrared camera. Several design options on the coldplate, i.e., diameter & height of fins and shape & pattern of fin arrays, were examined. The effects of coolant flow rate and coolant type on the performance of coldplate were also studied. The overall thermal resistance and pressure drop of the coldplate were used to compare the efficiency of a series of coldplate design. Based on the CFD results, the effect of coldplate pin fins design on the thermal resistance is small. However, the pressure drop of the coldplate is quite sensitive to the design of pin fins. It is also noted that the fin height of coldplate can be reduced by 10% without degrading the performance of coldplate.
{"title":"Design of Liquid Cooled Coldplate for the Inverter of the Hybrid Electric Vehicle","authors":"C. E. Jih, K. Chen, T. Abraham, V. Siddapureddy, R. Poulson, V. A. Sankaran","doi":"10.1115/imece2000-1540","DOIUrl":"https://doi.org/10.1115/imece2000-1540","url":null,"abstract":"\u0000 As the performance of the advanced electric systems increases, the packaging densities and power requirements will also increase. The reliability of these components will depend on the ability of the packaging system to transport heat away from the device. In this paper, a liquid-cooled coldplate for the inverter of hybrid electric vehicle was designed by using Computational Fluid Dynamics (CFD) technique. The main features of inverter packaging include power module, capacitors, busbar, gate driver, gate power supply, coldplate, sensors, & controllers. How to effectively dissipate the heat from power module to the coldplate is the focus of this study. The 3-phase full bridge power module consists of 12 IGBTs and 12 diodes. The silicon dies of IGBT or diode were soldered to the direct-bonded ceramic (DBC) A1N substrate, and to the copper base plate. Then the whole module was mounted mechanically onto an aluminum coldplate using thermal grease at the interface. The maximum allowable die junction temperature is 125°C. The commercial CFD code, FLUENT, was used here to study the flow field and heat transfer of the coldplate. In order to have confidence in the CFD prediction, the temperature distribution of an inverter assembly was obtained from FLUENT and then verified with the measurement from an infrared camera. Several design options on the coldplate, i.e., diameter & height of fins and shape & pattern of fin arrays, were examined. The effects of coolant flow rate and coolant type on the performance of coldplate were also studied. The overall thermal resistance and pressure drop of the coldplate were used to compare the efficiency of a series of coldplate design. Based on the CFD results, the effect of coldplate pin fins design on the thermal resistance is small. However, the pressure drop of the coldplate is quite sensitive to the design of pin fins. It is also noted that the fin height of coldplate can be reduced by 10% without degrading the performance of coldplate.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120966904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Application of solid/liquid phase change material (PCM) for passive cooling of electronic modules is on the increase. A simplified method of predicting the thermal performance of passive cooling systems is needed for efficient design of thermal storage systems. This paper presents an experimental and approximate analytical method for quick estimation of the rate of thermal transport in solid/liquid PCM during and after the melting process. However, the emphasis of this paper is on the transport phenomena after the melting process is completed. This research is motivated in part by the need for a simplified analytical method of predicting the rate of heat transfer in buoyancy-driven fluids within a partitioned enclosure, and the need for a fundamental understanding of the rate of heat transfer in liquid melt after the phase change phenomena. These needs are of practical importance for efficient design of a thermal energy storage system. The approximate analytical model serves as a quick method of studying the performance of a thermosyphon system.
{"title":"An Analytical and Experimental Model for a Thermosyphon That Employs Solid/Liquid Phase Change Materials","authors":"A. Nnanna, K. T. Harris, A. Haji-sheikh","doi":"10.1115/imece2000-1520","DOIUrl":"https://doi.org/10.1115/imece2000-1520","url":null,"abstract":"\u0000 Application of solid/liquid phase change material (PCM) for passive cooling of electronic modules is on the increase. A simplified method of predicting the thermal performance of passive cooling systems is needed for efficient design of thermal storage systems. This paper presents an experimental and approximate analytical method for quick estimation of the rate of thermal transport in solid/liquid PCM during and after the melting process. However, the emphasis of this paper is on the transport phenomena after the melting process is completed. This research is motivated in part by the need for a simplified analytical method of predicting the rate of heat transfer in buoyancy-driven fluids within a partitioned enclosure, and the need for a fundamental understanding of the rate of heat transfer in liquid melt after the phase change phenomena. These needs are of practical importance for efficient design of a thermal energy storage system. The approximate analytical model serves as a quick method of studying the performance of a thermosyphon system.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126752765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Smith, J. V. Bubb, O. Popp, T. Diller, Stephen J. Hevey
A transient, in-situ method was examined for calibrating thin-film heat flux gauges using experimental data generated from both convection and radiation tests. Also, a comparison is made between this transient method and the standard radiation substitution calibration technique. Six Vatell Corporation HFM-7 type heat flux gauges were mounted on the surface of a 2-D, first-stage turbine rotor blade. These gauges were subjected to radiation from a heat lamp and in a separate experiment to a convective heat flux generated by flow in a transonic cascade wind tunnel. A second set of convective tests were performed using jets of cooled air impinging on the surface of the gauges. Direct measurements were simultaneously taken of both the time-resolved heat flux and surface temperature on the blade. The heat flux input was used to predict a surface temperature response using a one-dimensional, semi-infinite conduction model into a substrate with known thermal properties. The sensitivities of the gauges were determined by correlating the semi-infinite predicted temperature response to the measured temperature response. A finite-difference code was used to model the penetration of the heat flux into the substrate in order to estimate the time for which the semi-infinite assumption was valid. The results from these tests showed that the gauges accurately record both the convection and radiation modes of heat transfer. The radiation and convection tests yielded gauge sensitivities which agreed to within ±11%.
{"title":"A Comparison of Radiation Versus Convection Calibration of Thin-Film Heat Flux Gauges","authors":"D. Smith, J. V. Bubb, O. Popp, T. Diller, Stephen J. Hevey","doi":"10.1115/imece1999-1106","DOIUrl":"https://doi.org/10.1115/imece1999-1106","url":null,"abstract":"\u0000 A transient, in-situ method was examined for calibrating thin-film heat flux gauges using experimental data generated from both convection and radiation tests. Also, a comparison is made between this transient method and the standard radiation substitution calibration technique. Six Vatell Corporation HFM-7 type heat flux gauges were mounted on the surface of a 2-D, first-stage turbine rotor blade. These gauges were subjected to radiation from a heat lamp and in a separate experiment to a convective heat flux generated by flow in a transonic cascade wind tunnel. A second set of convective tests were performed using jets of cooled air impinging on the surface of the gauges. Direct measurements were simultaneously taken of both the time-resolved heat flux and surface temperature on the blade. The heat flux input was used to predict a surface temperature response using a one-dimensional, semi-infinite conduction model into a substrate with known thermal properties. The sensitivities of the gauges were determined by correlating the semi-infinite predicted temperature response to the measured temperature response. A finite-difference code was used to model the penetration of the heat flux into the substrate in order to estimate the time for which the semi-infinite assumption was valid. The results from these tests showed that the gauges accurately record both the convection and radiation modes of heat transfer. The radiation and convection tests yielded gauge sensitivities which agreed to within ±11%.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116791563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this study is to model the heat transfer and fluid flow in a tunnel pasteurizer, which can be used to predict the operation status of the pasteurization process. This modeling is very useful when some changes must be made to the design, operation, or the types of products to be pasteurized. Moreover, the model can be used to provide valuable data for the optimization of the pasteurization design. In the modeling two approaches have been adopted. One is the Lumped Parameter Method (LPM), which is used to model the whole pasteurization system, including pipes, zones and heat exchangers. The other one is the Computational Fluid Dynamics (CFD) technology for calculations of the heat transfer and fluid flow rates in the heat exchanger tank. A steady state model in a tunnel pasteurizer has been developed by using the LPM. The temperatures of the spray water and the products in the pasteurization process were calculated by employing this model. The comparisons showed reasonably good agreements between the predicted results and the experimental data. The pressure variations along the regenerative loops were also calculated. With the CFD technology, the numerical calculations of heat transfer and fluid flow have been performed on the temperature distribution in the cylindrical heat exchanger tank that provides a hot water through the top and a cold water through the bottom of tank. There are two outlets. In the heat exchanger tank, the tube arrays are set along the azimuth direction of the tank. This is a thermally stratified layered water tank that can control the four zones of the water temperatures.
{"title":"Numerical Modeling of Turbulent Heat Transfer and Fluid Flow in a Tunnel Pasteurization Process","authors":"Y. Zheng, R. Amano","doi":"10.1115/imece1999-1122","DOIUrl":"https://doi.org/10.1115/imece1999-1122","url":null,"abstract":"\u0000 The purpose of this study is to model the heat transfer and fluid flow in a tunnel pasteurizer, which can be used to predict the operation status of the pasteurization process. This modeling is very useful when some changes must be made to the design, operation, or the types of products to be pasteurized. Moreover, the model can be used to provide valuable data for the optimization of the pasteurization design.\u0000 In the modeling two approaches have been adopted. One is the Lumped Parameter Method (LPM), which is used to model the whole pasteurization system, including pipes, zones and heat exchangers. The other one is the Computational Fluid Dynamics (CFD) technology for calculations of the heat transfer and fluid flow rates in the heat exchanger tank. A steady state model in a tunnel pasteurizer has been developed by using the LPM. The temperatures of the spray water and the products in the pasteurization process were calculated by employing this model. The comparisons showed reasonably good agreements between the predicted results and the experimental data. The pressure variations along the regenerative loops were also calculated. With the CFD technology, the numerical calculations of heat transfer and fluid flow have been performed on the temperature distribution in the cylindrical heat exchanger tank that provides a hot water through the top and a cold water through the bottom of tank. There are two outlets. In the heat exchanger tank, the tube arrays are set along the azimuth direction of the tank. This is a thermally stratified layered water tank that can control the four zones of the water temperatures.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125054360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the most destructive forces in large urban fires is the occurrence of fire whirls. Despite the relatively recent experimental and numerical simulation studies on the global behaviors of small-scale whirling fires, much of the whirling fire phenomena still remain unknown. The purpose of this experimental study is to examine closely the detailed structures of the velocity and temperature fields in a stable whirling flame generated in a vertical square channel with symmetrical corner gaps by both physical measurements using conventional means and by quantitative observations using both a high-speed motion camera and a thermographic infrared camera. The results showed a rather complex non-uniform velocity and temperature field in the lower half of the whirling flame and could provide an important basis to validate the fire field models for the study of real large-scale fire whirls.
{"title":"Measurements of Fire Whirls From a Single Flame in a Vertical Square Channel With Symmetrical Corner Gaps","authors":"K. Satoh","doi":"10.1115/imece1999-1116","DOIUrl":"https://doi.org/10.1115/imece1999-1116","url":null,"abstract":"\u0000 One of the most destructive forces in large urban fires is the occurrence of fire whirls. Despite the relatively recent experimental and numerical simulation studies on the global behaviors of small-scale whirling fires, much of the whirling fire phenomena still remain unknown. The purpose of this experimental study is to examine closely the detailed structures of the velocity and temperature fields in a stable whirling flame generated in a vertical square channel with symmetrical corner gaps by both physical measurements using conventional means and by quantitative observations using both a high-speed motion camera and a thermographic infrared camera. The results showed a rather complex non-uniform velocity and temperature field in the lower half of the whirling flame and could provide an important basis to validate the fire field models for the study of real large-scale fire whirls.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126193378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Measurements and monitoring of flow patterns are one of the most important parameters in many industrial processes such as mass transfer in all types of reactors, heat exchangers, and tribo systems. The objective of this paper is to report and analyze the experimental data obtained in the process of development of Computer-Aided Measurement System of flow patterns based on in-situ mixture dynamic parameters. The measurement systems of in-situ parameters are interfaced with a Computer-Aided-Data-Acquisition-System (CADAS). The developed apparatus allowed measurement of the in-situ flow parameters of the mixture simultaneously including concentration and pressures monitored in large and small time scales. Using a previously developed computer-aided-measurement system and electronic sensors, experimental data of in-situ spatial concentration, in-situ gas/liquid velocities, pressures, and other parameters were obtained for steady-state conditions in an adiabatic two phase air-water flow system which consisted of a small square vertical channel.
{"title":"Experimental Laboratory Research on Computer-Aided System for Determining Fluid Flow Patterns in Air-Water Two-Phase Flow","authors":"J. Keska, Michael D. Smith, Quinn F. Dolan","doi":"10.1115/imece1999-1132","DOIUrl":"https://doi.org/10.1115/imece1999-1132","url":null,"abstract":"\u0000 Measurements and monitoring of flow patterns are one of the most important parameters in many industrial processes such as mass transfer in all types of reactors, heat exchangers, and tribo systems. The objective of this paper is to report and analyze the experimental data obtained in the process of development of Computer-Aided Measurement System of flow patterns based on in-situ mixture dynamic parameters. The measurement systems of in-situ parameters are interfaced with a Computer-Aided-Data-Acquisition-System (CADAS). The developed apparatus allowed measurement of the in-situ flow parameters of the mixture simultaneously including concentration and pressures monitored in large and small time scales. Using a previously developed computer-aided-measurement system and electronic sensors, experimental data of in-situ spatial concentration, in-situ gas/liquid velocities, pressures, and other parameters were obtained for steady-state conditions in an adiabatic two phase air-water flow system which consisted of a small square vertical channel.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125428961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The particle image velocimetry measurement technique was used to measure the whole-volume, three-dimensional, transient velocity field generated by a single air bubble rising in stagnant water in a small diameter pipe. The three-dimensional flow field was reconstructed using a stereoscopic technique. Conditional averages of the velocity fields for the situations when the bubble rises close to the center of the pipe, and close to the pipe wall were determined, and the turbulent motion generated in the continuous liquid phase for both situations was studied.
{"title":"Experimental Study of the Transient Turbulence Generated by a Bubble Using PIV","authors":"J. Ortíz-Villafuerte, W. Schmidl, Y. Hassan","doi":"10.1115/imece1999-1131","DOIUrl":"https://doi.org/10.1115/imece1999-1131","url":null,"abstract":"\u0000 The particle image velocimetry measurement technique was used to measure the whole-volume, three-dimensional, transient velocity field generated by a single air bubble rising in stagnant water in a small diameter pipe. The three-dimensional flow field was reconstructed using a stereoscopic technique. Conditional averages of the velocity fields for the situations when the bubble rises close to the center of the pipe, and close to the pipe wall were determined, and the turbulent motion generated in the continuous liquid phase for both situations was studied.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129310340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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