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Daotong Chong - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on the mechanism of pressure oscillation for Steam Jet in stable condensation region
Experimental Thermal and Fluid Science, 2017Co-Authors: Binbin Qiu, Daotong Chong, Junjie Yan, Shripad T RevankarAbstract:Abstract The pressure oscillations for Steam Jet in stable condensation region are investigated experimentally. Steam at pressure 0.2–0.6 MPa is injected into subcooled water at one atmosphere pressure with Steam mass flux ranging from 298 to 865 kg/(m 2 s), with water subcooling from 70 to 40 K. The Steam plume shapes have been recorded and are compared with the pressure oscillation. The pressure oscillation for Steam Jet in stable condensation region is caused by the oscillation of Steam plume length. When the Steam plume length is the longest, the pressure oscillation has negative peak value and vice versa. Based on the experimental data and the change of Steam plume shapes, a new phenomenological model of pressure oscillation is developed. The model also provides a method to obtain the Steam plume length using the pressure oscillation. The prediction errors of the peak pressure oscillation are within ±30% of experimental values.
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research on the Steam Jet length with different nozzle structures
Experimental Thermal and Fluid Science, 2015Co-Authors: Daotong Chong, Quanbin Zhao, Fang Yuan, Wei Wang, Weixiong ChenAbstract:Abstract The effect of nozzle structure on the Steam Jet lengths of submerged condensation in quiescent water is investigated theoretically and experimentally. Two typical nozzles are analyzed and tested. Theoretical analysis shows that nozzle structure has a great influence on the Steam Jet length but was paid little attention before. Then a theoretical model for Steam Jet length with different nozzle structures is proposed based on the expansion and compression wave theory. Theoretical model indicates that Steam Jet length is greatly affected by nozzle structure. The Steam Jet length of straight pipe nozzle is longer than that of orifice nozzle under the same pool water temperature and Steam mass flux, and the Steam Jet length is inverse proportion to the maximum expansion ratio, approximately. Then the theoretical model is verified by the experimental results. Finally, a universal semi-empirical correlation considering the nozzle structure is proposed. The prediction length corresponds to the experimental data very well and the discrepancy is within ±25% for different nozzle structures for the Steam mass flux 400–800 kg·m −2 ·s −1 and water temperature 10–70 °C.
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experimental study on sonic Steam Jet condensation in quiescent subcooled water
Chemical Engineering Science, 2009Co-Authors: Xinzhuang Wu, Wenjun Li, Daotong ChongAbstract:Abstract Condensation heat transfer of sonic Steam Jet in subcooled water was investigated experimentally over a wide range of Steam mass flux and water temperature. Four different Steam plume shapes were observed in present test conditions, and condensation regime map was given based on Steam mass flux and water temperature. Maximum expansion ratio and dimensionless penetration length of the Steam Jet were also obtained in the ranges of 1.04–2.20 and 2.86–14.60, respectively. Then the semi-empirical correlations were given to predict the expansion ratio and penetration length, the results showed good agreement between the predictions and experiments. Moreover, temperature fields in the Steam plume and surrounding water were measured. Axial temperature distributions represented the four typical Steam plumes, and variation of the axial temperature confirmed existence of expansion and compression waves. Finally, surface renewal model was adopted to predict condensation heat transfer coefficients, which were in the range of 0.98–1.45 MW/m 2 K and mainly dependent on the physical property and Steam plume shape, including expansion angle, expansion ratio and penetration length.
Chul-hwa Song - One of the best experts on this subject based on the ideXlab platform.
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condensation dynamics of submerged Steam Jet in subcooled water
International Journal of Multiphase Flow, 2012Co-Authors: Soon Joon Hong, Goon Cherl Park, Chul-hwa SongAbstract:Abstract Condensation oscillation of submerged Steam Jet in water pool was investigated. From the experiments it was found that the dominant frequency of condensation oscillation was proportional to Steam mass flux for Steam mass flux under 300 kg/m2 s and inversely proportional for over 300 kg/m2 s. The frequency was always inversely proportional to pool temperature. For the high Steam mass flux region (over 300 kg/m2 s), one-dimensional mechanistic model was developed based on the balance of the kinetic energy that the Steam Jet gives and the pool water receives, adopting the submerged turbulent Jet theory. The proposed model excellently predicted the dominant frequencies for the Steam mass flux 300–900 kg/m2 s and water temperature 35–75 °C. For the higher water temperature, the developed model also could predict the dominant frequencies by adjusting the ratio of Jet expansion coefficients of vapor dominant region and liquid dominant region.
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Direct Contact Condensation of Steam Jet in a Pool
Advances in heat transfer, 2011Co-Authors: Chul-hwa Song, Yeon-sik KimAbstract:Abstract The phenomena of direct contact condensation (DCC) of a Steam Jet discharged in a water pool occur due to the actuation of Steam discharging devices submerged in a pool in many industrial processes. There are practically two kinds of technical concerns to consider. The first is the thermal mixing in the water pool, and the other is the thermo-hydraulically induced mechanical loads acting on the structures of relevant systems. The two concerns are interrelated with each other and can be well described only if the local behavior of condensing Steam Jets and the resultant turbulent Jet in a pool is well understood. In this paper, the DCC-related thermo-fluid dynamic features are discussed focusing on these two concerns. The fundamental characteristics of condensing Steam Jets, such as local characteristics of condensing Jets and the resultant turbulent Jet, are reviewed, both of which importantly affect the macroscopic circulation motion in a pool. Here the local behavior of condensing Jets includes the shapes of Steam Jet cavity, temperature and pressure profiles in a Steam Jet region, Jet expansion and penetration length, interfacial mass and heat transfer around the cavity, dynamic aspect of Steam Jet condensation, and the condensation regime map. Then a global motion analysis of thermal mixing in a pool is discussed from the viewpoints of the local hot spot and the thermal stratification with some practical applications to engineering design in mind.
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Overall Review of Steam Jet Condensation in a Next Generation Reactor Water Pool
Heat Transfer Volume 4, 2003Co-Authors: Yeon-sik Kim, Chul-hwa SongAbstract:In the advanced nuclear power plants including APR1400, the SDVS has been adopted to increase plant safety using the concept of a feed-and-bleed operation. In the case of the TLOFW(total loss of feedwater) in a PWR(pressurized water reactor), the POSRV(power operated safety relief valve) located at the top of the pressurizer is expected to open due to the pressurization of the reactor coolant system and discharge Steam and/or water mixture into the water pool, where the mixture is condensed. During the condensation of the mixture, thermal-hydraulic loads such as pressure and temperature variations are induced in the pool structure. For pool structure design, such thermal-hydraulic aspects should be considered. Understanding the phenomena of submerged Steam Jet condensation in a water pool is helpful for system designers to design proper pool structures, spargers, and supports etc. This paper reviews and evaluates Steam Jet condensation in a water pool for the physical phenomena of Steam condensation including condensation regime map, heat transfer coefficient, Steam plume, Steam Jet condensation load, and Steam Jet induced flow.Copyright © 2003 by ASME
Xinzhuang Wu - One of the best experts on this subject based on the ideXlab platform.
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condensation regime diagram for supersonic sonic Steam Jet in subcooled water
Nuclear Engineering and Design, 2009Co-Authors: Xinzhuang Wu, Wenjun LiAbstract:Abstract This study was designed to determine the behaviour of the flow patterns of supersonic and sonic Steam Jet condensation in subcooled water. The effects of Steam mass flux, water temperature and pressure ratio on the flow pattern were discussed. The results indicated that the flow pattern was not only affected by Steam mass flux and water temperature, but also affected significantly by pressure ratio. The expansion and contraction ratios of the Steam plume were influenced significantly by pressure ratio, and a correlation for predicting the expansion and contraction ratio was given based on the theoretical expansion ratio of sonic Steam Jet. At relatively low Steam mass flux and high water temperature, the transition of flow pattern from stable Jet to unstable Jet was observed, and a criterion of stable–unstable Jet transition was given. Moreover, the three-dimensional condensation regime maps, including stable Steam plume shapes and unstable Jet, for sonic and supersonic Steam Jet under different conditions were discussed. Four different shapes of the Steam plume occurred in sonic Steam Jet regime map, and six different shapes of the Steam plume occurred in supersonic Steam Jet regime map. The regime maps were also validated against the previous experiments.
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experimental study on sonic Steam Jet condensation in quiescent subcooled water
Chemical Engineering Science, 2009Co-Authors: Xinzhuang Wu, Wenjun Li, Daotong ChongAbstract:Abstract Condensation heat transfer of sonic Steam Jet in subcooled water was investigated experimentally over a wide range of Steam mass flux and water temperature. Four different Steam plume shapes were observed in present test conditions, and condensation regime map was given based on Steam mass flux and water temperature. Maximum expansion ratio and dimensionless penetration length of the Steam Jet were also obtained in the ranges of 1.04–2.20 and 2.86–14.60, respectively. Then the semi-empirical correlations were given to predict the expansion ratio and penetration length, the results showed good agreement between the predictions and experiments. Moreover, temperature fields in the Steam plume and surrounding water were measured. Axial temperature distributions represented the four typical Steam plumes, and variation of the axial temperature confirmed existence of expansion and compression waves. Finally, surface renewal model was adopted to predict condensation heat transfer coefficients, which were in the range of 0.98–1.45 MW/m 2 K and mainly dependent on the physical property and Steam plume shape, including expansion angle, expansion ratio and penetration length.
Wenjun Li - One of the best experts on this subject based on the ideXlab platform.
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condensation regime diagram for supersonic sonic Steam Jet in subcooled water
Nuclear Engineering and Design, 2009Co-Authors: Xinzhuang Wu, Wenjun LiAbstract:Abstract This study was designed to determine the behaviour of the flow patterns of supersonic and sonic Steam Jet condensation in subcooled water. The effects of Steam mass flux, water temperature and pressure ratio on the flow pattern were discussed. The results indicated that the flow pattern was not only affected by Steam mass flux and water temperature, but also affected significantly by pressure ratio. The expansion and contraction ratios of the Steam plume were influenced significantly by pressure ratio, and a correlation for predicting the expansion and contraction ratio was given based on the theoretical expansion ratio of sonic Steam Jet. At relatively low Steam mass flux and high water temperature, the transition of flow pattern from stable Jet to unstable Jet was observed, and a criterion of stable–unstable Jet transition was given. Moreover, the three-dimensional condensation regime maps, including stable Steam plume shapes and unstable Jet, for sonic and supersonic Steam Jet under different conditions were discussed. Four different shapes of the Steam plume occurred in sonic Steam Jet regime map, and six different shapes of the Steam plume occurred in supersonic Steam Jet regime map. The regime maps were also validated against the previous experiments.
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experimental study on sonic Steam Jet condensation in quiescent subcooled water
Chemical Engineering Science, 2009Co-Authors: Xinzhuang Wu, Wenjun Li, Daotong ChongAbstract:Abstract Condensation heat transfer of sonic Steam Jet in subcooled water was investigated experimentally over a wide range of Steam mass flux and water temperature. Four different Steam plume shapes were observed in present test conditions, and condensation regime map was given based on Steam mass flux and water temperature. Maximum expansion ratio and dimensionless penetration length of the Steam Jet were also obtained in the ranges of 1.04–2.20 and 2.86–14.60, respectively. Then the semi-empirical correlations were given to predict the expansion ratio and penetration length, the results showed good agreement between the predictions and experiments. Moreover, temperature fields in the Steam plume and surrounding water were measured. Axial temperature distributions represented the four typical Steam plumes, and variation of the axial temperature confirmed existence of expansion and compression waves. Finally, surface renewal model was adopted to predict condensation heat transfer coefficients, which were in the range of 0.98–1.45 MW/m 2 K and mainly dependent on the physical property and Steam plume shape, including expansion angle, expansion ratio and penetration length.
Junjie Yan - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on the mechanism of pressure oscillation for Steam Jet in stable condensation region
Experimental Thermal and Fluid Science, 2017Co-Authors: Binbin Qiu, Daotong Chong, Junjie Yan, Shripad T RevankarAbstract:Abstract The pressure oscillations for Steam Jet in stable condensation region are investigated experimentally. Steam at pressure 0.2–0.6 MPa is injected into subcooled water at one atmosphere pressure with Steam mass flux ranging from 298 to 865 kg/(m 2 s), with water subcooling from 70 to 40 K. The Steam plume shapes have been recorded and are compared with the pressure oscillation. The pressure oscillation for Steam Jet in stable condensation region is caused by the oscillation of Steam plume length. When the Steam plume length is the longest, the pressure oscillation has negative peak value and vice versa. Based on the experimental data and the change of Steam plume shapes, a new phenomenological model of pressure oscillation is developed. The model also provides a method to obtain the Steam plume length using the pressure oscillation. The prediction errors of the peak pressure oscillation are within ±30% of experimental values.
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Experimental study on the stable Steam Jet in subcooled water flow in a rectangular mix chamber
Experimental Thermal and Fluid Science, 2016Co-Authors: Xiao Zong, Jiping Liu, Xiaoping Yang, Yi Chen, Junjie YanAbstract:Abstract Two-phase Flow Steam Injector (TFSI) was a simple device without moving parts, which had been used in several industrial applications. As an important process of the TFSI, Steam-water Direct Contact Condensation (DCC) in stagnant water pool had been widely investigated. DCC had different features when occurring in a confined channel in water flow, which is more similar to the DCC process of that in TFSI. In present work, direct contact condensation of stable Steam Jet in subcooled water flow in a rectangular mix chamber was investigated experimentally. Rectangular Steam and water nozzles were adopted to form a quasi-planar structural flow flied and two different stable Steam Jets including conical Jet and ellipsoidal Jet were observed. The transition from stable Steam Jet to divergent Jet was observed and the transition criterion was also established. A three-dimensional regime diagram was presented and discussed based on Steam mass flux, water mass flux and inlet water temperature. In addition, temperature and pressure distributions on the bottom wall center for stable Steam Jet were measured. The peaks in temperature distributions evidenced the compression wave, whilst the nadirs in pressure distributions were evidence to the expansion wave. Furthermore, average heat transfer coefficients predicted by interfacial transport model due to turbulent intensity were in the range of 3.83–6.24 MW/m 2 K, which were in the same order of magnitude with previous investigations, and the discrepancies between predicted and experimental values were within ±30%.
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Condensation regime diagram for supersonic/sonic Steam Jet in subcooled water
Nuclear Engineering and Design, 2009Co-Authors: Junjie Yan, Dong-dong Pan, Guang-yao LiuAbstract:Abstract This study was designed to determine the behaviour of the flow patterns of supersonic and sonic Steam Jet condensation in subcooled water. The effects of Steam mass flux, water temperature and pressure ratio on the flow pattern were discussed. The results indicated that the flow pattern was not only affected by Steam mass flux and water temperature, but also affected significantly by pressure ratio. The expansion and contraction ratios of the Steam plume were influenced significantly by pressure ratio, and a correlation for predicting the expansion and contraction ratio was given based on the theoretical expansion ratio of sonic Steam Jet. At relatively low Steam mass flux and high water temperature, the transition of flow pattern from stable Jet to unstable Jet was observed, and a criterion of stable–unstable Jet transition was given. Moreover, the three-dimensional condensation regime maps, including stable Steam plume shapes and unstable Jet, for sonic and supersonic Steam Jet under different conditions were discussed. Four different shapes of the Steam plume occurred in sonic Steam Jet regime map, and six different shapes of the Steam plume occurred in supersonic Steam Jet regime map. The regime maps were also validated against the previous experiments.
