水平管内强制对流凝结换热的实验研究

AN EXPERIMENTAL INVESTIGATION OF FORCED CONVEC- TIVE CONDENSATION OF REFRIGERANT R-12 IN HORIZONTAL TUBE

一、引言 水平管内的凝结换热,由于其过程的复杂性,至今尚不足以从基本物理定律出发,定量地得出理论解析式,而主要计算关联式均来自实验研究。近三十年来,这方面文献报道较多,但是不同研究者推荐的关联式之间差别很大,有的相差一倍以上。本研究以R-12为工质,在较宽广的流量范围内(G=100—410kg/s·m^2)进行了管内凝结局部换热系数的实验研究。根据实验结果,对五个知名度较高的计算关联式进行了评价,并提出了新的局部换热系数关联式。

Forced convective condensation of refrigerant R-12 condensing in a horizontal tube is investigated experimentally. The test condenser consisted of five 13 mm I. D. by 16 mm O. D. copper tube sections, each 1.08 m long. The experimental results of local heat transfer coefficients are compared with the existing correlations. It's found that the correlation of Traviss ef al [4] predicted the data satisfactorily at high Reynolds numbers, but it is distinctly below this experimental results at low Reynolds numbers. New correlation is suggested and the agreement is within ±15% in the broad range of Reynolds numbers. It can be used for engineering design computation.