The Experts below are selected from a list of 1209 Experts worldwide ranked by ideXlab platform
Weihua Cai - One of the best experts on this subject based on the ideXlab platform.
-
the pressure drop and heat transfer characteristics of condensation flow with hydrocarbon mixtures in a Spiral Pipe under static and heaving conditions
International Journal of Refrigeration-revue Internationale Du Froid, 2019Co-Authors: Weihua Cai, Yiqiang Jiang, Haochun ZhangAbstract:Abstract A model based on ASNYS CFX was established to explore the pressure drop and heat transfer characteristics of condensation flow with hydrocarbon mixtures in a Spiral Pipe under static and heaving conditions, whose deviations are within ±15% compared to experimental ones. It considered the effects of motion parameters, operating parameters and structural parameters on frictional pressure drop and heat transfer coefficient for three hydrocarbon mixtures. The ranges of mass flux, vapor quality, heat flux, saturation pressure, hydraulic diameter, curvature diameter and inclination angle were 200–800 kg/(m 2 ·s), 0.3–0.9, 10–20 kW/m 2 , 2–4 MPa, 6–14 mm, 1.6–2.4 m and 6–14°, respectively. The results demonstrate that methane/ethane mixture has the best heat transfer and the smallest pressure drop among three mixtures. At static condition, as the vapor quality and mass flux increase and the saturation pressure and hydraulic diameter decrease, there are evident increases in heat transfer and pressure drop, whereas the impacts of curvature diameter, inclination angle and heat flux on them are insignificant. Meanwhile, the heaving motion affects pressure drop and heat transfer and makes it show better overall heat transfer performances, where the comprehensive heat transfer factors ( CHFs ) of 83.33% data points are more than 1. Further, the heaving effects increase with the increasing heaving amplitude and the decreasing heaving cycle.
-
numerical study on condensation heat transfer and pressure drop characteristics of methane upward flow in a Spiral Pipe under sloshing condition
International Journal of Heat and Mass Transfer, 2019Co-Authors: Yiqiang Jiang, Weihua Cai, Haochun ZhangAbstract:Abstract In order to explore condensation flow and heat transfer characteristics in the tube side of Spiral wound heat exchange (SWHE) used in floating liquefied natural gas (FLNG) field, a model was established to simulate methane condensation upward flow in a Spiral Pipe at different sloshing conditions, such as heave, roll and pitch conditions. The simulated results coincide with experiment ones, and the deviations are within ±15%. The effects of various parameters on frictional pressure drop and heat transfer coefficient were discussed in Pipes with curvature ratio of 0.003–0.007. The ranges of Reynolds numbers in vapor and liquid flows are respectively 154,944–697,251 and 18,190–127,331. It was found that at static conditions, both frictional pressure drop and heat transfer coefficient increase with the increase of mass flux and the decrease of saturation pressure and hydraulic diameter; with the increase of vapor quality, the heat transfer coefficient first increases and then decreases whereas the frictional pressure drop continuously increases; the effects of curvature diameter are slight. Meanwhile, in most cases, the sloshing motions can cause a remarkable heat transfer enhancement as well as a small decrease of frictional pressure drop. Further, the effects of heaving motion on flow and heat transfer are more obvious than the others, with the average drag reduction and heat transfer augmentation of 1.51% and 15.70%, respectively. These results are helpful for the understanding condensation characteristics in the Spiral Pipe at sloshing conditions, and for the design of SWHE used in FLNG field.
-
evaluation analysis of correlations for predicting void fraction of condensation hydrocarbon refrigerant upward flow in a Spiral Pipe
Applied Thermal Engineering, 2018Co-Authors: Weihua Cai, Weihua Cai, Jie Chen, Haochun Zhang, Yiqiang JiangAbstract:Abstract Accurate prediction of void fraction for condensation hydrocarbon refrigerant upward flow in a Spiral Pipe is very important for the tube-side design of Spiral wound heat exchange (SWHE) using in liquid natural gas (LNG) plants. Although scores of void fraction correlations have been developed until now, most of them are focus on two-phase flow in straight tubes and their applicability to Spiral Pipes needs to be evaluated. In this paper, the condensation void fraction characteristics were numerically investigated based on the verified model. 455 numerical data points of six refrigerants were obtained, under different operating and structural parameters. Based on these data, 96 void fraction correlations were evaluated, which covered the types of homogeneous, slip-ratio, Kαv,H, Lockhart-Martinelli parameter based, drift-flux, general and implicit, and finally the best five correlations were recommended which can well predict condensation void fraction in a Spiral Pipe within ±5% error. This study will provide some constructive instructions to predict void fraction for condensation hydrocarbon refrigerant upward flow in a Spiral Pipe, which is helpful in designing more effective SWHE used in large-scale LNG plants.
-
numerical study on condensation heat transfer and pressure drop characteristics of ethane propane mixture upward flow in a Spiral Pipe
International Journal of Heat and Mass Transfer, 2018Co-Authors: Weihua Cai, Haochun Zhang, Jie Chen, Yiqiang JiangAbstract:Abstract Spiral wound heat exchanges (SWHE) has been the most widely used in large-scale liquid natural gas (LNG) plants. However, few studies have been focused on the condensation heat transfer and pressure drop for hydrocarbon mixture refrigerant in SWHE tube side. In this paper, the condensation heat transfer and pressure drop characteristics for ethane/propane mixture upward flow in a Spiral Pipe were numerically investigated. The numerical model was established and verified based on the existing experimental results and new flow pattern observation experiments. It discussed the variation trends of void fraction, frictional pressure drop, heat transfer coefficient and heat and mass transfer resistance with various parameters, such as, vapor quality, mass flux, heat flux, saturation pressure and inclination angle. Comparing with the existing correlations, the results showed that Steiner’s correlation, modified Fuchs’s correlation, Boyko’s correlation could better predict the void fraction, frictional pressure drop, film heat transfer coefficient with mean absolute deviation of 6.08%, 10.67% and 13.06%, respectively. Meanwhile, modified Silver approach was used to modify the mixed effects of ethane/propane mixture on heat transfer. The study provides some constructive instructions to understand the condensation of zeotropic mixtures in the Spiral Pipe, and is helpful in designing more effective SWHE.
-
numerical study on the flow and heat transfer characteristics of forced convective condensation with propane in a Spiral Pipe
International Journal of Heat and Mass Transfer, 2018Co-Authors: Weihua Cai, Haochun Zhang, Jie Chen, Yiqiang JiangAbstract:Abstract In order to investigate the condensation heat transfer and pressure drop characteristics in tube-side flow of Spiral wound heat exchanger (SWHE), a computational model based on two-fluid multiphase model, k-e turbulence model and thermal phase change model was established considering the gravity and surface tension. Also, a calculation formula for mean interfacial length between vapor phase and liquid phase was deduced and the wall contact angle was discussed. Based on the above model, numerical simulations were carried out on the condensation flow and heat transfer for propane upward flow in a Spiral Pipe. Compared with experimental data, it shows that the errors for the simulation results based on the new model are within ±15% under different operating parameters. Meanwhile, the heat transfer coefficient and frictional pressure drop are mainly influenced by vapor quality, mass flux and saturation pressure while the heat flux almost does not affect them. Comparing with the existing correlations, the improved correlations based on Boyko’s correlation and Fuchs’s correlation have been developed to predict condensation heat transfer coefficients and frictional pressure drop. These results will provide some constructive instructions for the understanding of condensation heat transfer and pressure drop characteristics in the Spiral Pipe, as well as the design and prediction of condensation heat transfer and pressure drop performance in SWHE.
Haochun Zhang - One of the best experts on this subject based on the ideXlab platform.
-
the pressure drop and heat transfer characteristics of condensation flow with hydrocarbon mixtures in a Spiral Pipe under static and heaving conditions
International Journal of Refrigeration-revue Internationale Du Froid, 2019Co-Authors: Weihua Cai, Yiqiang Jiang, Haochun ZhangAbstract:Abstract A model based on ASNYS CFX was established to explore the pressure drop and heat transfer characteristics of condensation flow with hydrocarbon mixtures in a Spiral Pipe under static and heaving conditions, whose deviations are within ±15% compared to experimental ones. It considered the effects of motion parameters, operating parameters and structural parameters on frictional pressure drop and heat transfer coefficient for three hydrocarbon mixtures. The ranges of mass flux, vapor quality, heat flux, saturation pressure, hydraulic diameter, curvature diameter and inclination angle were 200–800 kg/(m 2 ·s), 0.3–0.9, 10–20 kW/m 2 , 2–4 MPa, 6–14 mm, 1.6–2.4 m and 6–14°, respectively. The results demonstrate that methane/ethane mixture has the best heat transfer and the smallest pressure drop among three mixtures. At static condition, as the vapor quality and mass flux increase and the saturation pressure and hydraulic diameter decrease, there are evident increases in heat transfer and pressure drop, whereas the impacts of curvature diameter, inclination angle and heat flux on them are insignificant. Meanwhile, the heaving motion affects pressure drop and heat transfer and makes it show better overall heat transfer performances, where the comprehensive heat transfer factors ( CHFs ) of 83.33% data points are more than 1. Further, the heaving effects increase with the increasing heaving amplitude and the decreasing heaving cycle.
-
numerical study on condensation heat transfer and pressure drop characteristics of methane upward flow in a Spiral Pipe under sloshing condition
International Journal of Heat and Mass Transfer, 2019Co-Authors: Yiqiang Jiang, Weihua Cai, Haochun ZhangAbstract:Abstract In order to explore condensation flow and heat transfer characteristics in the tube side of Spiral wound heat exchange (SWHE) used in floating liquefied natural gas (FLNG) field, a model was established to simulate methane condensation upward flow in a Spiral Pipe at different sloshing conditions, such as heave, roll and pitch conditions. The simulated results coincide with experiment ones, and the deviations are within ±15%. The effects of various parameters on frictional pressure drop and heat transfer coefficient were discussed in Pipes with curvature ratio of 0.003–0.007. The ranges of Reynolds numbers in vapor and liquid flows are respectively 154,944–697,251 and 18,190–127,331. It was found that at static conditions, both frictional pressure drop and heat transfer coefficient increase with the increase of mass flux and the decrease of saturation pressure and hydraulic diameter; with the increase of vapor quality, the heat transfer coefficient first increases and then decreases whereas the frictional pressure drop continuously increases; the effects of curvature diameter are slight. Meanwhile, in most cases, the sloshing motions can cause a remarkable heat transfer enhancement as well as a small decrease of frictional pressure drop. Further, the effects of heaving motion on flow and heat transfer are more obvious than the others, with the average drag reduction and heat transfer augmentation of 1.51% and 15.70%, respectively. These results are helpful for the understanding condensation characteristics in the Spiral Pipe at sloshing conditions, and for the design of SWHE used in FLNG field.
-
numerical study on condensation heat transfer and pressure drop characteristics of ethane propane mixture upward flow in a Spiral Pipe
International Journal of Heat and Mass Transfer, 2018Co-Authors: Weihua Cai, Haochun Zhang, Jie Chen, Yiqiang JiangAbstract:Abstract Spiral wound heat exchanges (SWHE) has been the most widely used in large-scale liquid natural gas (LNG) plants. However, few studies have been focused on the condensation heat transfer and pressure drop for hydrocarbon mixture refrigerant in SWHE tube side. In this paper, the condensation heat transfer and pressure drop characteristics for ethane/propane mixture upward flow in a Spiral Pipe were numerically investigated. The numerical model was established and verified based on the existing experimental results and new flow pattern observation experiments. It discussed the variation trends of void fraction, frictional pressure drop, heat transfer coefficient and heat and mass transfer resistance with various parameters, such as, vapor quality, mass flux, heat flux, saturation pressure and inclination angle. Comparing with the existing correlations, the results showed that Steiner’s correlation, modified Fuchs’s correlation, Boyko’s correlation could better predict the void fraction, frictional pressure drop, film heat transfer coefficient with mean absolute deviation of 6.08%, 10.67% and 13.06%, respectively. Meanwhile, modified Silver approach was used to modify the mixed effects of ethane/propane mixture on heat transfer. The study provides some constructive instructions to understand the condensation of zeotropic mixtures in the Spiral Pipe, and is helpful in designing more effective SWHE.
-
numerical study on the flow and heat transfer characteristics of forced convective condensation with propane in a Spiral Pipe
International Journal of Heat and Mass Transfer, 2018Co-Authors: Weihua Cai, Haochun Zhang, Jie Chen, Yiqiang JiangAbstract:Abstract In order to investigate the condensation heat transfer and pressure drop characteristics in tube-side flow of Spiral wound heat exchanger (SWHE), a computational model based on two-fluid multiphase model, k-e turbulence model and thermal phase change model was established considering the gravity and surface tension. Also, a calculation formula for mean interfacial length between vapor phase and liquid phase was deduced and the wall contact angle was discussed. Based on the above model, numerical simulations were carried out on the condensation flow and heat transfer for propane upward flow in a Spiral Pipe. Compared with experimental data, it shows that the errors for the simulation results based on the new model are within ±15% under different operating parameters. Meanwhile, the heat transfer coefficient and frictional pressure drop are mainly influenced by vapor quality, mass flux and saturation pressure while the heat flux almost does not affect them. Comparing with the existing correlations, the improved correlations based on Boyko’s correlation and Fuchs’s correlation have been developed to predict condensation heat transfer coefficients and frictional pressure drop. These results will provide some constructive instructions for the understanding of condensation heat transfer and pressure drop characteristics in the Spiral Pipe, as well as the design and prediction of condensation heat transfer and pressure drop performance in SWHE.
Yiqiang Jiang - One of the best experts on this subject based on the ideXlab platform.
-
the pressure drop and heat transfer characteristics of condensation flow with hydrocarbon mixtures in a Spiral Pipe under static and heaving conditions
International Journal of Refrigeration-revue Internationale Du Froid, 2019Co-Authors: Weihua Cai, Yiqiang Jiang, Haochun ZhangAbstract:Abstract A model based on ASNYS CFX was established to explore the pressure drop and heat transfer characteristics of condensation flow with hydrocarbon mixtures in a Spiral Pipe under static and heaving conditions, whose deviations are within ±15% compared to experimental ones. It considered the effects of motion parameters, operating parameters and structural parameters on frictional pressure drop and heat transfer coefficient for three hydrocarbon mixtures. The ranges of mass flux, vapor quality, heat flux, saturation pressure, hydraulic diameter, curvature diameter and inclination angle were 200–800 kg/(m 2 ·s), 0.3–0.9, 10–20 kW/m 2 , 2–4 MPa, 6–14 mm, 1.6–2.4 m and 6–14°, respectively. The results demonstrate that methane/ethane mixture has the best heat transfer and the smallest pressure drop among three mixtures. At static condition, as the vapor quality and mass flux increase and the saturation pressure and hydraulic diameter decrease, there are evident increases in heat transfer and pressure drop, whereas the impacts of curvature diameter, inclination angle and heat flux on them are insignificant. Meanwhile, the heaving motion affects pressure drop and heat transfer and makes it show better overall heat transfer performances, where the comprehensive heat transfer factors ( CHFs ) of 83.33% data points are more than 1. Further, the heaving effects increase with the increasing heaving amplitude and the decreasing heaving cycle.
-
numerical study on condensation heat transfer and pressure drop characteristics of methane upward flow in a Spiral Pipe under sloshing condition
International Journal of Heat and Mass Transfer, 2019Co-Authors: Yiqiang Jiang, Weihua Cai, Haochun ZhangAbstract:Abstract In order to explore condensation flow and heat transfer characteristics in the tube side of Spiral wound heat exchange (SWHE) used in floating liquefied natural gas (FLNG) field, a model was established to simulate methane condensation upward flow in a Spiral Pipe at different sloshing conditions, such as heave, roll and pitch conditions. The simulated results coincide with experiment ones, and the deviations are within ±15%. The effects of various parameters on frictional pressure drop and heat transfer coefficient were discussed in Pipes with curvature ratio of 0.003–0.007. The ranges of Reynolds numbers in vapor and liquid flows are respectively 154,944–697,251 and 18,190–127,331. It was found that at static conditions, both frictional pressure drop and heat transfer coefficient increase with the increase of mass flux and the decrease of saturation pressure and hydraulic diameter; with the increase of vapor quality, the heat transfer coefficient first increases and then decreases whereas the frictional pressure drop continuously increases; the effects of curvature diameter are slight. Meanwhile, in most cases, the sloshing motions can cause a remarkable heat transfer enhancement as well as a small decrease of frictional pressure drop. Further, the effects of heaving motion on flow and heat transfer are more obvious than the others, with the average drag reduction and heat transfer augmentation of 1.51% and 15.70%, respectively. These results are helpful for the understanding condensation characteristics in the Spiral Pipe at sloshing conditions, and for the design of SWHE used in FLNG field.
-
numerical study on condensation heat transfer and pressure drop characteristics of ethane propane mixture upward flow in a Spiral Pipe
International Journal of Heat and Mass Transfer, 2018Co-Authors: Weihua Cai, Haochun Zhang, Jie Chen, Yiqiang JiangAbstract:Abstract Spiral wound heat exchanges (SWHE) has been the most widely used in large-scale liquid natural gas (LNG) plants. However, few studies have been focused on the condensation heat transfer and pressure drop for hydrocarbon mixture refrigerant in SWHE tube side. In this paper, the condensation heat transfer and pressure drop characteristics for ethane/propane mixture upward flow in a Spiral Pipe were numerically investigated. The numerical model was established and verified based on the existing experimental results and new flow pattern observation experiments. It discussed the variation trends of void fraction, frictional pressure drop, heat transfer coefficient and heat and mass transfer resistance with various parameters, such as, vapor quality, mass flux, heat flux, saturation pressure and inclination angle. Comparing with the existing correlations, the results showed that Steiner’s correlation, modified Fuchs’s correlation, Boyko’s correlation could better predict the void fraction, frictional pressure drop, film heat transfer coefficient with mean absolute deviation of 6.08%, 10.67% and 13.06%, respectively. Meanwhile, modified Silver approach was used to modify the mixed effects of ethane/propane mixture on heat transfer. The study provides some constructive instructions to understand the condensation of zeotropic mixtures in the Spiral Pipe, and is helpful in designing more effective SWHE.
-
numerical study on the flow and heat transfer characteristics of forced convective condensation with propane in a Spiral Pipe
International Journal of Heat and Mass Transfer, 2018Co-Authors: Weihua Cai, Haochun Zhang, Jie Chen, Yiqiang JiangAbstract:Abstract In order to investigate the condensation heat transfer and pressure drop characteristics in tube-side flow of Spiral wound heat exchanger (SWHE), a computational model based on two-fluid multiphase model, k-e turbulence model and thermal phase change model was established considering the gravity and surface tension. Also, a calculation formula for mean interfacial length between vapor phase and liquid phase was deduced and the wall contact angle was discussed. Based on the above model, numerical simulations were carried out on the condensation flow and heat transfer for propane upward flow in a Spiral Pipe. Compared with experimental data, it shows that the errors for the simulation results based on the new model are within ±15% under different operating parameters. Meanwhile, the heat transfer coefficient and frictional pressure drop are mainly influenced by vapor quality, mass flux and saturation pressure while the heat flux almost does not affect them. Comparing with the existing correlations, the improved correlations based on Boyko’s correlation and Fuchs’s correlation have been developed to predict condensation heat transfer coefficients and frictional pressure drop. These results will provide some constructive instructions for the understanding of condensation heat transfer and pressure drop characteristics in the Spiral Pipe, as well as the design and prediction of condensation heat transfer and pressure drop performance in SWHE.
Sunghak Lee - One of the best experts on this subject based on the ideXlab platform.
-
effects of microstructure and Pipe forming strain on yield strength before and after Spiral Pipe forming of api x70 and x80 linePipe steel sheets
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Seok Su Sohn, Seung Youb Han, Jin Ho Bae, Hyoung Seop Kim, Sunghak LeeAbstract:Abstract API X70 and X80 linePipe steel sheets were shaped in the form of Pipe with different strains (thickness/diameter ratio) by Spiral Pipe forming. Tension specimens taken from steel sheets or Pipes at an interval of 2.5 mm were tested, and their yielding behavior, yield strength, and yield ratio before and after forming were analyzed. In the Pipes, the continuous yielding and low yield ratios were shown in the inner side, whereas the discontinuous yielding and high yield ratios were shown in the outer side. This was because the Bauschinger effect and the strain hardening effect were mainly dominant in the inner and outer sides, respectively. The overall yield strength after Spiral piping was defined by the competing effect of the strain hardening and the Bauschinger effect. The competing effects depended on the microstructure and the Pipe forming strains. The low-temperature transformation microstructures were preferred for achieving the larger increase of overall yield strength after Pipe forming. For a specific microstructure an optimization of the yield strength can also be achieved by controlling the Pipe forming strain in order to maximize the strain hardening effect and to minimize the Bauschinger effect.
Seok Su Sohn - One of the best experts on this subject based on the ideXlab platform.
-
Effects of microstructure and Pipe forming strain on yield strength before and after Spiral Pipe forming of API X70 and X80 linePipe steel sheets
'Elsevier BV', 2018Co-Authors: Seok Su Sohn, Seung Youb Han, Jin Ho Bae, Hs KimAbstract:API X70 and X80 linePipe steel sheets were shaped in the form of Pipe with different strains (thickness/diameter ratio) by Spiral Pipe forming. Tension specimens taken from steel sheets or Pipes at an interval of 2.5 mm were tested, and their yielding behavior, yield strength, and yield ratio before and after forming were analyzed. In the Pipes, the continuous yielding and low yield ratios were shown in the inner side, whereas the discontinuous yielding and high yield ratios were shown in the outer side. This was because the Bauschinger effect and the strain hardening effect were mainly dominant in the inner and outer sides, respectively. The overall yield strength after Spiral piping was defined by the competing effect of the strain hardening and the Bauschinger effect. The competing effects depended on the microstructure and the Pipe forming strains. The low-temperature transformation microstructures were preferred for achieving the larger increase of overall yield strength after Pipe forming. For a specific microstructure an optimization of the yield strength can also be achieved by controlling the Pipe forming strain in order to maximize the strain hardening effect and to minimize the Bauschinger effect. (C) 2013 Elsevier B.V. All rights reserved.X1121
-
effects of microstructure and Pipe forming strain on yield strength before and after Spiral Pipe forming of api x70 and x80 linePipe steel sheets
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Seok Su Sohn, Seung Youb Han, Jin Ho Bae, Hyoung Seop Kim, Sunghak LeeAbstract:Abstract API X70 and X80 linePipe steel sheets were shaped in the form of Pipe with different strains (thickness/diameter ratio) by Spiral Pipe forming. Tension specimens taken from steel sheets or Pipes at an interval of 2.5 mm were tested, and their yielding behavior, yield strength, and yield ratio before and after forming were analyzed. In the Pipes, the continuous yielding and low yield ratios were shown in the inner side, whereas the discontinuous yielding and high yield ratios were shown in the outer side. This was because the Bauschinger effect and the strain hardening effect were mainly dominant in the inner and outer sides, respectively. The overall yield strength after Spiral piping was defined by the competing effect of the strain hardening and the Bauschinger effect. The competing effects depended on the microstructure and the Pipe forming strains. The low-temperature transformation microstructures were preferred for achieving the larger increase of overall yield strength after Pipe forming. For a specific microstructure an optimization of the yield strength can also be achieved by controlling the Pipe forming strain in order to maximize the strain hardening effect and to minimize the Bauschinger effect.