Experimental Investigation On Heat Transfer Of Supercritical Pressure Water Flowing In Sub-channel With Triangle Distribution Of SCWR

Supercritical water cooled reactor(SCWR) is one of the six new fourth-generation nuclear reactors, which are the most important research and development of GIF. The thermal-hydraulic of reactor is the key of SCWR, the paper investigates the heat transfer of sub-channel with triangle distribution of SCWR through the experimental method, which provide the test data and prediction method of heat transfer characteristics to thermodynamic criterion and design of SCWR. The research has great engineering application values and theoretical significances for SCWR.Heat transfer and flow resistance of supercritical pressure water investigated within the sub-channel with triangle distribution, which was formed that the diameter D of fuel rods was 8mm and the pitch-to-diameter ratio P/D was 1.4. Within the range of pressure from 23 to 28 MPa, inner wall heat flux from 200 to 800 k W/m2, and mass velocity from 700 to 1300 kg/(m2×s), this paper researched the temperature distribution in the axial direction and the typical heat transfer characteristics of sub-channel with triangle distribution, analyzed the impacts of system parameters on the heat transfer characteristics, fitted the correlation of heat transfer of supercritical pressure water in the sub-channel with triangle distribution. The experimental data were analyzed, which were compared with the classic correlations.Through the experimental investigation on heat transfer of supercritical pressure water flowing in sub-channel with triangle distribution of SCWR, the temperature of the sub-channel with triangle distribution in the axial direction is gradually increased. Because of the heat transfer enhancement, the temperature of the sub-channel with triangle distribution increases slowly and the heat transfer coefficient has the peak at the large specific heat region. When the pressure and the mass velocity are the same, with an increase in heat flux, the wall temperature increases and the peak of heat transfer coefficient decreases. When the mass velocity and heat flux are the same, the wall temperature increases and he peak of heattransfer coefficient decreases as the pressure increases. The mass velocity can enhance the heat transfer, with the increase in mass velocity, the wall temperature decreases and the heat transfer coefficient increases. The heat transfer coefficient is less influential by the heat flux and the pressure in the low enthalpy range. However, with the bulk enthalpy entering into the large specific heat region, the heat transfer coefficient is greatly influenced by heat flux and pressure. The peak of the heat transfer coefficient decrease greatly as heat flux and pressure increases. When the bulk enthalpy passes the large specific heat region, the influence of heat transfer coefficient begins to decrease by heat flux and pressure. The result also shows that the heat transfer characteristics will change or heat transfer enhancement will be weakened beyond the certain range, when the heat flux reaches 800 k W/m2, the temperature of the wall and the heat transfer coefficient get abnormal, and heat transfer coefficient has no peak. When the pressure reaches 28 MPa, the heat transfer enhancement is weakened in the large specific heat region. When the mass velocity increased to a certain extent, the heat transfer enhancement is worse than the low mass velocity.Based on the experimental investigation on heat transfer of supercritical pressure water flowing in sub-channel with triangle distribution of SCWR, two new correlations were obtained by fitting the test data to predict the heat transfer of supercritical pressure water flowing in sub-channel with triangle distribution in the high enthalpy area and low enthalpy value area, The two fitting correlations’ calculation results fit for the experimental data quite well. The supercritical heat transfer correlations were assessed against the current set of data in the experimental investigation, it was found that the classic correlations give the bad prediction and the prediction results is too large. Jackson correlation and Bishop correlation give the better prediction.The support of The National Natural Science Foundation of China and the Plan of Innovative Talents in Universities of Henan Province(NO.2012HASTIT018) is gratefully acknowledged.