【摘要】 本文对超临界压力二氧化碳在烧结多孔介质的竖直圆管中的对流换热进行了实验研究。分析了入口温度超过准临界温度、颗粒直径为0．2-0．28 mm的多孔圆管中,压力、流量、热流密度以及流动方向对超临界二氧化碳对流换热的影响。结果表明,准临界点附近剧烈变物性的影响使得超临界二氧化碳在多孔结构中的对流换热非常复杂。对流换热随着温度远离准临界温度和热流密度的增加不断减弱;流量对对流换热的影响比较复杂。在准临界温度附近,浮升力对换热有一定的影响。更多还原

【Abstract】 Convection heat transfer of supercritical CO2 in a vertical sintered porous tube was investigated experimentally. The effects of pressure, mass flow rate, heat flux and flow direction on convection heat transfer were investigated in the sintered porous tube with particle diameter 0.2~0.28mm when the inlet temperature was over the pseudocritical temperature. The results show that the convection heat transfer of supercritical CO2 in porous media is very complicated because of the strongly variations of the thermophysical properties near the pseudocritical temperature. Convection heat transfer decreases with the fluid temperature away from the pseudocritical temperature and with the increase of heat flux. The effect of mass flow rate on convection heat transfer is complicated. The buoyancy affects obviously the convection heat transfer near the pseudocritical temperature.更多还原