The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Jiping Liu - One of the best experts on this subject based on the ideXlab platform.
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experimental study on the interfacial wave and local Heat Transfer coefficient of stable steam jet condensation in a rectangular mix chamber
International Journal of Heat and Mass Transfer, 2018Co-Authors: Xiao Zong, Jiping Liu, Junjie YanAbstract:Abstract An experimental study on the interfacial wave and local Heat Transfer coefficient of stable steam jet condensation in a rectangular mix chamber was carried out. In experiments, the interfacial wave amplitude was obtained and analyzed, and an empirical correlation predicting the dimensionless wave amplitude was established. To evaluate the local Average Heat Transfer coefficient, a thermal equilibrium model was developed, and the local Average Heat Transfer characteristics were obtained and discussed. The results indicate that the interfacial wave amplitude increases with water mass flux and the axial dimensionless position, decreases with the steam mass flux, and changes little with inlet water temperature. The local Average Heat Transfer coefficients are within the range of 0.98–6.24 MW/m2 °C, and they increase with the interfacial wave amplitude. The interfacial fluctuation could promote the steam jet condensation and corresponding Heat Transfer coefficients.
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experimental study on the condensation of supersonic steam jet submerged in quiescent subcooled water steam plume shape and Heat Transfer
International Journal of Multiphase Flow, 2007Co-Authors: Junjie Yan, Shufeng Shao, Yan Cao, Jiping LiuAbstract:Abstract The condensation of supersonic steam jet submerged in the quiescent subcooled water was investigated experimentally. The results indicated that the shape of steam plume was controlled by the steam exit pressure and water temperature. Six different shapes of steam plume were observed under the present test conditions. Their distribution as a function of the steam exit pressures and water temperatures was given. As the steam mass velocity and water temperature increase, the measured maximum expansion ratio and dimensionless penetration length of steam plume were in the ranges of 1.08–1.95 and 3.05–13.15, respectively. The Average Heat Transfer coefficient of supersonic steam jet condensation was found to be in the range of 0.63–3.44 MW/m2K. An analytical model of steam plume was found and the correlations to predict the maximum expansion ratio, dimensionless penetration length and Average Heat Transfer coefficient were also investigated.
Ximin Zhang - One of the best experts on this subject based on the ideXlab platform.
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experimental study on direct contact condensation of stable steam jet in water flow in a vertical pipe
International Journal of Heat and Mass Transfer, 2013Co-Authors: Liejin Guo, Suifeng Zou, Juanwen Chen, Ximin ZhangAbstract:Abstract Direct contact condensation is widely used in industrial applications due to its highly efficient Heat and mass Transfer. Many experimental and theoretical works have been performed on steam jet condensation in stagnant water in pool. However, the condensation of steam jet in water flow in pipes is not yet fully understood. Here, experiments are performed to study the direct contact condensation of stable steam jet in water flow in a vertical pipe. By using high speed camera and mobile thermocouple probe, we investigate condensation characteristics including the plume shape, plume length, temperature distribution, Average Heat Transfer coefficient, and Average Nusselt number. Five different plume shapes (hemispherical, conical, ellipsoidal, cylinder, and divergent) are identified visually, and their distribution is described in a three-dimensional condensation regime diagram based on steam mass flux, water temperature, and Reynolds number of water flow. The dimensionless plume length and Average Heat Transfer coefficient are found to be within the range of 0.29–4.64 and 0.34–11.36 MW/m 2 K, respectively. Besides, empirical correlations are obtained for the dimensionless plume length, Average Heat Transfer coefficient, and Average Nusselt number as a function of three dimensionless parameters, i.e., dimensionless steam mass flux, condensation driving potential, and Reynolds number of water flow. The dimensionless radial temperature decreases exponentially from the center to the pipe wall and shows good self-similarity.
Junjie Yan - One of the best experts on this subject based on the ideXlab platform.
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experimental study on the interfacial wave and local Heat Transfer coefficient of stable steam jet condensation in a rectangular mix chamber
International Journal of Heat and Mass Transfer, 2018Co-Authors: Xiao Zong, Jiping Liu, Junjie YanAbstract:Abstract An experimental study on the interfacial wave and local Heat Transfer coefficient of stable steam jet condensation in a rectangular mix chamber was carried out. In experiments, the interfacial wave amplitude was obtained and analyzed, and an empirical correlation predicting the dimensionless wave amplitude was established. To evaluate the local Average Heat Transfer coefficient, a thermal equilibrium model was developed, and the local Average Heat Transfer characteristics were obtained and discussed. The results indicate that the interfacial wave amplitude increases with water mass flux and the axial dimensionless position, decreases with the steam mass flux, and changes little with inlet water temperature. The local Average Heat Transfer coefficients are within the range of 0.98–6.24 MW/m2 °C, and they increase with the interfacial wave amplitude. The interfacial fluctuation could promote the steam jet condensation and corresponding Heat Transfer coefficients.
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experimental study on the condensation of supersonic steam jet submerged in quiescent subcooled water steam plume shape and Heat Transfer
International Journal of Multiphase Flow, 2007Co-Authors: Junjie Yan, Shufeng Shao, Yan Cao, Jiping LiuAbstract:Abstract The condensation of supersonic steam jet submerged in the quiescent subcooled water was investigated experimentally. The results indicated that the shape of steam plume was controlled by the steam exit pressure and water temperature. Six different shapes of steam plume were observed under the present test conditions. Their distribution as a function of the steam exit pressures and water temperatures was given. As the steam mass velocity and water temperature increase, the measured maximum expansion ratio and dimensionless penetration length of steam plume were in the ranges of 1.08–1.95 and 3.05–13.15, respectively. The Average Heat Transfer coefficient of supersonic steam jet condensation was found to be in the range of 0.63–3.44 MW/m2K. An analytical model of steam plume was found and the correlations to predict the maximum expansion ratio, dimensionless penetration length and Average Heat Transfer coefficient were also investigated.
Liejin Guo - One of the best experts on this subject based on the ideXlab platform.
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experimental study on direct contact condensation of stable steam jet in water flow in a vertical pipe
International Journal of Heat and Mass Transfer, 2013Co-Authors: Liejin Guo, Suifeng Zou, Juanwen Chen, Ximin ZhangAbstract:Abstract Direct contact condensation is widely used in industrial applications due to its highly efficient Heat and mass Transfer. Many experimental and theoretical works have been performed on steam jet condensation in stagnant water in pool. However, the condensation of steam jet in water flow in pipes is not yet fully understood. Here, experiments are performed to study the direct contact condensation of stable steam jet in water flow in a vertical pipe. By using high speed camera and mobile thermocouple probe, we investigate condensation characteristics including the plume shape, plume length, temperature distribution, Average Heat Transfer coefficient, and Average Nusselt number. Five different plume shapes (hemispherical, conical, ellipsoidal, cylinder, and divergent) are identified visually, and their distribution is described in a three-dimensional condensation regime diagram based on steam mass flux, water temperature, and Reynolds number of water flow. The dimensionless plume length and Average Heat Transfer coefficient are found to be within the range of 0.29–4.64 and 0.34–11.36 MW/m 2 K, respectively. Besides, empirical correlations are obtained for the dimensionless plume length, Average Heat Transfer coefficient, and Average Nusselt number as a function of three dimensionless parameters, i.e., dimensionless steam mass flux, condensation driving potential, and Reynolds number of water flow. The dimensionless radial temperature decreases exponentially from the center to the pipe wall and shows good self-similarity.
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Turbulent Heat Transfer in a horizontal helically coiled tube
Heat Transfer?Asian Research, 1999Co-Authors: Bofeng Bai, Liejin Guo, Ziping Feng, Xuejun ChenAbstract:An experiment has been conducted in detail to study the turbulent Heat Transfer in horizontal helically coiled tubes over a wide range of experimental parameters. We found that the enhancement of Heat Transfer in the coils results from the effects of turbulent and secondary flows. With Reynolds number increasing to a high level, the contribution of the secondary flow becomes less to enhance Heat Transfer, and the Average Heat Transfer coefficient of the coil is closer to that in straight tubes under the same conditions. The local Heat Transfer coefficients are not evenly distributed along both the tube axis and the periphery on the cross section. The local Heat Transfer coefficients on the outside are three or four times those on the inside, which is half of the Average Heat Transfer. A correlation is proposed to describe the distribution of the Heat Transfer coefficients at a cross section. The Average cross-section Heat Transfer coefficients are distributed along the tube axis. The Average value at the outlet section should not be taken as the Average Heat Transfer coefficient. © 1999 Scripta Technica, Heat Trans Asian Res, 28(5): 395–403, 1999
Daeyun Ji - One of the best experts on this subject based on the ideXlab platform.
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enhancement of condensation Heat Transfer in the presence of non condensable gas using steam jet method
International Journal of Heat and Mass Transfer, 2019Co-Authors: Daeyun JiAbstract:Abstract In this study, the use of the steam jet method to destroy the mixed boundary layer of steam and non-condensable gas (NCG) was researched in order to enhance the condensation Heat Transfer performance. An experimental facility was designed and manufactured in which steam was injected vertically into a single aluminum tube. Both the initial chamber pressure related to the amount of NCG and the bulk chamber pressure after the normal steam injection were tested. The time and enhancement parameters were obtained, including the steam jet continuance time, the maximum Heat Transfer enhancement ratio, the Average Heat Transfer enhancement ratio and the Average overall Heat Transfer coefficient. The results of the experiment indicate that after the steam jet injection, the maximum Heat Transfer enhancement ratio increased by at least 137%, and the Average Heat Transfer enhancement ratio increased by at least 118%. In addition, as the NCG mass fraction increased, the values of the continuance time, maximum Heat Transfer enhancement ratio, Average Heat Transfer enhancement ratio, and Average overall Heat Transfer coefficient improved. Thus, it was confirmed that the steam jet injection method, under the conditions of an accident in which a large amount of NCG flows into the condenser, can effectively improve the condensation performance. Finally, the idea of a bundle-type condenser which is applied by the steam jet method was proposed.
