低雷诺数条件下超临界压力CO_2换热实验研究

Experimental Investigation of Convection Heat Transfer of CO_2 at Supercritical Pressures in a Vertical Circular Tube at Low Re

在低雷诺数条件下(Rein=1970和750),对超临界压力CO2在垂直圆管(d=2 mm)内向上流动和向下流动时的对流换热进行了实验研究。实验结果表明:当Rein=1970时,在热流密度较高的情况下,在管子的入口处向上流动会出现局部壁面温度峰值和谷值,而在向下流动时未观察到此类似现象;当Rein=750时,向上、向下流动壁面温度的变化趋势和换热规律类似。

Convection heat transfer during upward flow of CO2 at supercritical pressures in a vertical circular tube （d=2mm） at low Reynolds numbers ranged from 750 to 1 970 has been experimentally investigated. The results show that the local wall temperature decrease was observed in upward flow at low heat fluxes and the local wall temperature peak at high heat fluxes with upward flow for Re=1970 which were not observed. The trend of wall temperature and the regularity of heat transfer are similar for upward and downward flows.