竖直圆管中超临界压力CO2在低雷诺数下对流换热研究

本文对竖直圆管中超临界压力二氧化碳在低雷诺数条件下的对流换热进行了实验研究和数值模拟。实验中分析了不同入口温度、热流密度以及流动方向等对超临界CO2流动和换热的影响。实验结果与计算结果的比较表明:在热流密度较小的情况下实验结果与数值计算结果基本吻合;而在热流密度较大的情况下,由于浮升力的影响,流动可能提前从层流转变为湍流,使换热强化。

CONVECTION HEAT TRANSFER OF CO2 AT SUPERCRITICAL PRESSURES AND LOW REYNOLDS NUMBER IN A VERTICAL TUBE

Convection heat transfer of CO2 at supercritical pressures in a vertical tube at low Re was investigated experimentally and numerically. The tests investigated the effects of inlet temperature, heat flux and flow direction on the convection heat transfer. For small heat fluxes, the experimental data agreed well with the numerical results. However, for relatively large heat fluxes, the measured heat transfer coefficients were higher than prechited by laminar flow analysis probably because the flow transitioned early from laminar to turbulent due to the influence of buoyancy.