平行流蒸发器内气液两相流分配均匀性实验研究

平行流蒸发器内气液两相(特别是液相)在各扁管间的分配对其传热性能影响较大,如果各扁管间的气液分配不均匀其传热性能将显著地下降.在不同气-液流量下实验研究了6种不同形式的平行流蒸发器的分支管液体流量分配情况,实验中观察到流型以环状流为主.研究发现,对于竖直向下流动和竖直向上流动,用通过增加管径的方法不能改善液体流量在各分支管的分配,而主管中气液入口的位置对于流量分配均匀性影响较大.

Experimental Study of the Distribution Uniformity of the Gas-liquid Two-phase Flow in a Parallel Flow Evaporator

The distribution of the gas-liquid two-phase flow (especially the liquid phase) in various flat tubes of a parallel flow evaporator exercises a relatively big influence on its heat transfer performance.If the gas and liquid distribution in various flat tubes is not uniform,the above-mentioned performance will deteriorate remarkably.At different gas and liquid flow rates,the authors have experimentally studied the liquid flow distribution in six forms of branch pipes of a parallel flow evaporator.During the test,it has been determined that the annular flow pattern predominates.It has been found that for a vertical descending and ascending flow,the method of increasing the tube diameter can not improve the liquid flow distribution in various branch pipes,but the location of the gas and liquid inlet in the main pipe has a relatively big influence on the uniformity of the flow distribution.