小尺度流道换热器流动特性实验研究

Experimental study of flow characteristics in heat exchanger with miniscale channels

在单相强迫对流情况下,对不同当量直径,流道截面形状分别为矩形或三角形的小尺度流道换热器,以水和乙二醇溶液为介质,进行实验研究,并与常规尺度流道换热器的流动特性进行比较,结果表明：小尺度流道内流动阻力系数低于常规尺度流道,矩形流道换热器阻力特性明显优于三角形流道换热器,流动阻力系数f随当量直径的增大而增大,阻力系数与介质Pr数无关,小尺度流道内流体流动的临界雷诺数Rec在700-1200之间。

The experimental study of flow characteristics has been conducted for water and ethylene-glycol solution flowing in the heat exchanger with rectangular or triangular microscale channels that have equivalent diameters of 0.55mm, 0.91mm, 1.38mm and 5mm. The experimental restdts show that flow friction factors of miniscale channels are smaller than that of normal channels, flow characteristics of rectangular channels are evidently better than that of triangular channels, and the flow friction factor decreases along with increasing Reynolds number. Besides, the flow friction factor is independent of Prandfl number, and the critical Reynolds number at which the flow transits to turbulent flow is 700- 1200.