不同体系对流传热膜系数测定的实验研究

选用牛顿冷却定律作为对流传热实验的测试原理,通过建立不同体系的传热系统,即水蒸汽—空气传热系统、乙醇水溶液蒸汽—空气传热系统,分别对普通管换热器和强化管换热器进行了强制对流传热实验研究。确定了在相应条件下冷流体对流传热膜系数的关联式。普通管换热器对流传热膜系数的关联式:Nu=0.01473Re0.61Pr0.4;强化管换热器对流传热膜系数的关联式:Nu=0.0251Re0.821Pr0.4;其计算值与实验结果符合良好。此实验方法可以测出蒸汽冷凝膜系数和管内对流传热系数。

Measurement of Film Heat Transfer Coefficient with Convection of Different Systems: An Experimental Study

Under the guidance of Newton's Cooling Law and with steam-air and ethanol aqueous solution + steam-air heat transfer systems,heat-transfer experiments with forced convection were conducted on heat exchangers with common pipes and intensified pipes.It is concluded that the film heat transfer coefficient with common pipes is: Nu= 0.014 73Re0.61Pr0.4;and that for intensified pipes is: Nu= 0.025 1Re0.821Pr0.4.The calculation data conform well with experimental results.By this method,the film condensation coefficient of steam and the coefficient of conduit convection heat transfer may also be determined.