【摘要】 本文对超临界二氧化碳在竖直细圆管中的对流换热进行了实验研究,研究了入口温度、流体流量、热流密度及浮升力等对换热的影响。结果表明,超临界压力条件下流体的进口温度、流量和热流密度对对流换热有很大的影响。当流量比较大而热流密度比较低时,物性的变化相对较弱,计算结果与实验数据基本吻合;而当流量比较小而热流密度比较高时,物性的变化相当剧烈,计算结果与实验数据有很大差异。更多还原

【Abstract】 Convection heat transfer of CO2 at supercritical pressures in a vertical mini-tube with a diameter of 0.948 mm was investigated experimentally. The tests investigated the effects of inlet temperature, mass flow rate, heat flux and buoyancy on the convection heat transfer. All these parameters significantly influenced the convective heat transfer. For large mass flow rates was large and small heat fluxes, the variation of thermophysical properties was relatively unimportant so the experimental data agreed well with calculated results. However, when the thermophysical property variations were influential, the numerical predictions differed greatly from the experimental data.更多还原