圆管内氦氙混合气体与超临界二氧化碳换热特性对比分析OA北大核心CSTPCD

The miniaturization and high compactness of reactor systems are the research focus of multipurpose ener-gy supply on land.However,energy conversion with direct thermal-dynamic cycles poses extremely high require-ments for the choice of coolants.In this work,the heat transfer characteristics in a circular tube are calculated by numerical simulation method to compare the physical properties of two coolants and analyze the effects of different heating power,inlet velocity,and inlet temperature on the coolant heat transfer coefficient,thus clarifying the suit-ability of working fluids for helium-xenon(He-Xe)gas mixtures and supercritical carbon dioxide(S-CO2).In this paper,an empirical model of heat transfer in a circular tube filled with two coolants is proposed.The results show that the convective heat transfer coefficient is relatively high when the heating power of the reactor exceeds 100 kW/m2 and the inlet flow rate is greater than 10 m/s.Furthermore,there exists a maximum when the inlet temperature of the helium-xenon mixture is about 1 000～1 200 K,and the supercritical carbon dioxide is about 550～600 K.Finally,in the high Reynolds number region(Re>104),the D-B type fitting relationship of the two coolants is in good agreement with the calculated values.The calculation in this paper can provide data and model basis for the development of new reactors.