The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform
Xu Cheng - One of the best experts on this subject based on the ideXlab platform.
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experimental study on heat transfer to supercritical water in 2 2 rod bundle with wire wraps
Experimental Thermal and Fluid Science, 2016Co-Authors: Da Liu, Meng Zhao, Xu ChengAbstract:Abstract Experimental studies on heat transfer to supercritical water in 2 × 2 rod bundle with wire wraps are performed at Shanghai Jiaotong University. The test section consists of two channels separated by a square steel assembly box with round corners. Water flows downward in the first channel and then turns upward in the second channel to cool the 2 × 2 rod bundle with wire wraps installed inside the assembly box. The bundle consists of four heater rods of 10 mm in O.D. and 1.18 in. pitch-to-diameter ratio. Experimental parameter ranges cover pressure from 23.0 MPa to 26.0 MPa, mass flux from 400 kg/m 2 s to 1400 kg/m 2 s, heat flux from 300 kW/m 2 to 1000 kW/m 2 and bulk temperature from 280 °C to 500 °C. The Fluid Enthalpy in the first channel increases due to the heat transfer through the assembly box when flowing downward. Heat transfer deterioration is observed in the bundle. The degree of the deterioration is moderated in the developed region due to the mixing by the wire wraps. Significant non-uniformity of circumferential wall-temperature distribution around the heater rods is observed. Effects of various parameters on heat transfer behavior inside the 2 × 2 rod bundle are similar to those observed in a tube. The heat transfer enhancement due to the wire wraps becomes remarkable under a high mass flux condition. The Jackson and Fewster correlation and Bishop et al. correlation give the best predictions when evaluated against the experimental data.
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experimental studies on heat transfer to supercritical water in 2 2 rod bundle with two channels
Nuclear Engineering and Design, 2015Co-Authors: Da Liu, Yao Xiao, Xu ChengAbstract:Abstract The experiment of heat transfer to supercritical water in 2 × 2 rod bundle is performed at Shanghai Jiao Tong University. The test section consists of two channels separated by a square steel assembly box with rounded corners. Water flows downward in the first channel and then turns upward in the second channel to cool the 2 × 2 rod bundle installed inside the assembly box. The bundle consists of four heated rods of 10 mm in O.D. and 1.18 in pitch-to-diameter ratio. The Fluid Enthalpy in the first channel increases due to the heat transfer through the assembly box when flowing downward. The minimum Fluid Enthalpy increase in the first channel appears at the pseudo-critical region due to the small temperature difference between the two channels. Effects of various parameters on heat transfer behavior inside the 2 × 2 rod bundle are similar to those observed in tube or annuli. No special phenomenon in heat transfer is observed during the mass flux and power transient. The steady-state heat transfer correlation is applicable to predict the heat transfer in the mass or power transient sequence. In addition, the importance of several dimensionless numbers and the accuracy of 20 heat transfer correlations are assessed. It is concluded that the buoyancy parameter proposed by Cheng et al. (2009) shows unique effect on heat transfer coefficient. Among the 20 selected heat transfer correlations, the correlations of Jackson and Fewster (1975) and Bishop et al. (1964) give the best predictions when compared with the experimental data.
Da Liu - One of the best experts on this subject based on the ideXlab platform.
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experimental study on heat transfer to supercritical water in 2 2 rod bundle with wire wraps
Experimental Thermal and Fluid Science, 2016Co-Authors: Da Liu, Meng Zhao, Xu ChengAbstract:Abstract Experimental studies on heat transfer to supercritical water in 2 × 2 rod bundle with wire wraps are performed at Shanghai Jiaotong University. The test section consists of two channels separated by a square steel assembly box with round corners. Water flows downward in the first channel and then turns upward in the second channel to cool the 2 × 2 rod bundle with wire wraps installed inside the assembly box. The bundle consists of four heater rods of 10 mm in O.D. and 1.18 in. pitch-to-diameter ratio. Experimental parameter ranges cover pressure from 23.0 MPa to 26.0 MPa, mass flux from 400 kg/m 2 s to 1400 kg/m 2 s, heat flux from 300 kW/m 2 to 1000 kW/m 2 and bulk temperature from 280 °C to 500 °C. The Fluid Enthalpy in the first channel increases due to the heat transfer through the assembly box when flowing downward. Heat transfer deterioration is observed in the bundle. The degree of the deterioration is moderated in the developed region due to the mixing by the wire wraps. Significant non-uniformity of circumferential wall-temperature distribution around the heater rods is observed. Effects of various parameters on heat transfer behavior inside the 2 × 2 rod bundle are similar to those observed in a tube. The heat transfer enhancement due to the wire wraps becomes remarkable under a high mass flux condition. The Jackson and Fewster correlation and Bishop et al. correlation give the best predictions when evaluated against the experimental data.
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heat transfer to supercritical water in a 2 2 rod bundle
Annals of Nuclear Energy, 2015Co-Authors: Da Liu, Meng ZhaoAbstract:Abstract An experimental study on heat transfer to supercritical water flowing in a 2 × 2 rod bundle test section with two channels is carried out at Shanghai Jiao Tong University. The bundle consists of four heated rods with an OD of 10 mm and a pitch-to-diameter ratio of 1.18. The 2 × 2 rod bundle is inserted into a square assembly box with rounded corners by which the test section is separated into two channels. Water flows downward in the first channel between the pressure tube and the assembly box and then turns upward in the second channel inside the assembly box to cool the four heated rods, which are directly heated by DC power. The experimental conditions are as follows: pressure ranging from 23 to 26 MPa, mass flux ranging from 400 to 1200 kg/m 2 s, heat flux between 300 and 1000 kW/m 2 , and bulk Fluid temperatures ranging from 200 to 480 °C. The heat transfer through the assembly box is strongly affected by the temperature difference between the two channels. The minimum Fluid Enthalpy increase in the first channel appears near the pseudo-critical temperature region. Non-uniformity of circumferential wall-temperature distribution around the heated rod is observed. The effects of various parameters on heat transfer behavior inside the 2 × 2 rod bundle are similar to effects observed in tubes. Six developed correlations are compared with the test data. The correlations of Jackson and Fewster (1975) and Bishop et al. (1964) provide the best predictions of the test data among the selected correlations.
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experimental studies on heat transfer to supercritical water in 2 2 rod bundle with two channels
Nuclear Engineering and Design, 2015Co-Authors: Da Liu, Yao Xiao, Xu ChengAbstract:Abstract The experiment of heat transfer to supercritical water in 2 × 2 rod bundle is performed at Shanghai Jiao Tong University. The test section consists of two channels separated by a square steel assembly box with rounded corners. Water flows downward in the first channel and then turns upward in the second channel to cool the 2 × 2 rod bundle installed inside the assembly box. The bundle consists of four heated rods of 10 mm in O.D. and 1.18 in pitch-to-diameter ratio. The Fluid Enthalpy in the first channel increases due to the heat transfer through the assembly box when flowing downward. The minimum Fluid Enthalpy increase in the first channel appears at the pseudo-critical region due to the small temperature difference between the two channels. Effects of various parameters on heat transfer behavior inside the 2 × 2 rod bundle are similar to those observed in tube or annuli. No special phenomenon in heat transfer is observed during the mass flux and power transient. The steady-state heat transfer correlation is applicable to predict the heat transfer in the mass or power transient sequence. In addition, the importance of several dimensionless numbers and the accuracy of 20 heat transfer correlations are assessed. It is concluded that the buoyancy parameter proposed by Cheng et al. (2009) shows unique effect on heat transfer coefficient. Among the 20 selected heat transfer correlations, the correlations of Jackson and Fewster (1975) and Bishop et al. (1964) give the best predictions when compared with the experimental data.
Jianguo Wang - One of the best experts on this subject based on the ideXlab platform.
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comparison of the heat transfer characteristics of supercritical pressure water to that of subcritical pressure water in vertically upward tubes
International Journal of Multiphase Flow, 2011Co-Authors: Jianguo Wang, Tingkuan ChenAbstract:A systematic comparison was made between the forced convection heat transfer characteristics of the supercritical pressure water and that of the subcritical pressure water in vertically-upward tubes. It was found that, severe heat transfer deterioration did not occur in the vertically-upward internally-ribbed tube at supercritical pressures, and the variations in the inside wall temperature with the bulk Fluid Enthalpy experienced three stages, namely, the continuously increasing stage, the smoothly changing stage and another continuously increasing stage at the supercritical pressures; however, at subcritical pressures, there existed at least four stages for the variation of the inside tube wall temperature, i.e., the continuously increasing stage, the basically unchanging stage, the sharply rising stage and another continuously increasing stage. The heat transfer coefficients in the subcritical two-phase region, in which the heat transfer deterioration did not occur, were much greater than those in the heat transfer enhancement region of supercritical pressure water. In the large specific heat region of supercritical pressure water, the enhanced heat transfer was impaired by increasing the heat flux; however, in the subcritical two-phase region, the higher the heat flux, the greater the heat transfer coefficient would be. It was also found that the heat transfer deterioration of supercritical pressure water was similar in mechanism to the DNB (departure from nucleate boiling) at subcritical pressures.
Meng Zhao - One of the best experts on this subject based on the ideXlab platform.
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experimental study on heat transfer to supercritical water in 2 2 rod bundle with wire wraps
Experimental Thermal and Fluid Science, 2016Co-Authors: Da Liu, Meng Zhao, Xu ChengAbstract:Abstract Experimental studies on heat transfer to supercritical water in 2 × 2 rod bundle with wire wraps are performed at Shanghai Jiaotong University. The test section consists of two channels separated by a square steel assembly box with round corners. Water flows downward in the first channel and then turns upward in the second channel to cool the 2 × 2 rod bundle with wire wraps installed inside the assembly box. The bundle consists of four heater rods of 10 mm in O.D. and 1.18 in. pitch-to-diameter ratio. Experimental parameter ranges cover pressure from 23.0 MPa to 26.0 MPa, mass flux from 400 kg/m 2 s to 1400 kg/m 2 s, heat flux from 300 kW/m 2 to 1000 kW/m 2 and bulk temperature from 280 °C to 500 °C. The Fluid Enthalpy in the first channel increases due to the heat transfer through the assembly box when flowing downward. Heat transfer deterioration is observed in the bundle. The degree of the deterioration is moderated in the developed region due to the mixing by the wire wraps. Significant non-uniformity of circumferential wall-temperature distribution around the heater rods is observed. Effects of various parameters on heat transfer behavior inside the 2 × 2 rod bundle are similar to those observed in a tube. The heat transfer enhancement due to the wire wraps becomes remarkable under a high mass flux condition. The Jackson and Fewster correlation and Bishop et al. correlation give the best predictions when evaluated against the experimental data.
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heat transfer to supercritical water in a 2 2 rod bundle
Annals of Nuclear Energy, 2015Co-Authors: Da Liu, Meng ZhaoAbstract:Abstract An experimental study on heat transfer to supercritical water flowing in a 2 × 2 rod bundle test section with two channels is carried out at Shanghai Jiao Tong University. The bundle consists of four heated rods with an OD of 10 mm and a pitch-to-diameter ratio of 1.18. The 2 × 2 rod bundle is inserted into a square assembly box with rounded corners by which the test section is separated into two channels. Water flows downward in the first channel between the pressure tube and the assembly box and then turns upward in the second channel inside the assembly box to cool the four heated rods, which are directly heated by DC power. The experimental conditions are as follows: pressure ranging from 23 to 26 MPa, mass flux ranging from 400 to 1200 kg/m 2 s, heat flux between 300 and 1000 kW/m 2 , and bulk Fluid temperatures ranging from 200 to 480 °C. The heat transfer through the assembly box is strongly affected by the temperature difference between the two channels. The minimum Fluid Enthalpy increase in the first channel appears near the pseudo-critical temperature region. Non-uniformity of circumferential wall-temperature distribution around the heated rod is observed. The effects of various parameters on heat transfer behavior inside the 2 × 2 rod bundle are similar to effects observed in tubes. Six developed correlations are compared with the test data. The correlations of Jackson and Fewster (1975) and Bishop et al. (1964) provide the best predictions of the test data among the selected correlations.
Tingkuan Chen - One of the best experts on this subject based on the ideXlab platform.
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comparison of the heat transfer characteristics of supercritical pressure water to that of subcritical pressure water in vertically upward tubes
International Journal of Multiphase Flow, 2011Co-Authors: Jianguo Wang, Tingkuan ChenAbstract:A systematic comparison was made between the forced convection heat transfer characteristics of the supercritical pressure water and that of the subcritical pressure water in vertically-upward tubes. It was found that, severe heat transfer deterioration did not occur in the vertically-upward internally-ribbed tube at supercritical pressures, and the variations in the inside wall temperature with the bulk Fluid Enthalpy experienced three stages, namely, the continuously increasing stage, the smoothly changing stage and another continuously increasing stage at the supercritical pressures; however, at subcritical pressures, there existed at least four stages for the variation of the inside tube wall temperature, i.e., the continuously increasing stage, the basically unchanging stage, the sharply rising stage and another continuously increasing stage. The heat transfer coefficients in the subcritical two-phase region, in which the heat transfer deterioration did not occur, were much greater than those in the heat transfer enhancement region of supercritical pressure water. In the large specific heat region of supercritical pressure water, the enhanced heat transfer was impaired by increasing the heat flux; however, in the subcritical two-phase region, the higher the heat flux, the greater the heat transfer coefficient would be. It was also found that the heat transfer deterioration of supercritical pressure water was similar in mechanism to the DNB (departure from nucleate boiling) at subcritical pressures.