矩形微通道内两相流摩擦压降特性及计算方法

Frictional pressure drop and calculating method of two-phase flow in rectangular microchannel

使用表面张力不同的纯水和乙醇作为液体,用氮气作为气体,在水平矩形微通道(d_(h)=0.29 mm)中开展两相流摩擦压降的实验研究,对通道进出口的压力进行了测量。结合流型说明了表面张力对摩擦压降产生的影响,并将实验压降值与均相流模型和分相流模型的预测值进行了对比,结果表明:在低压降区域,均相流模型预测值与实验值符合较好。针对于微小通道提出的分相流模型中,Zhang关系式预测结果与实验值符合稍好,但预测值整体大于实验值。根据实验分析中Chisholm系数C和L-M系数X之间存在的规律,同时考虑分液相雷诺数(Re_(L))、邦德数(Bo),对Chisholm关系式进行修正,修正计算式能很好预测实验结果。

The two-phase frictional pressure drop in microchannel was experimentally investigated.Using nitrogen as the gas-phase medium and the liquid with different surface tensions(pure water,ethanol)as the liquid-phase medium,experiments were conducted in horizontal rectangular microchannels with 0.29 mm inner diameter,during which the pressure at the inlet and outlet of the channel was measured.The influence of the surface tension on the frictional pressure drop was explained by the flow pattern.By comparing the experimental date with those predicted of homogeneous and separated flow model,the results show that the homogeneous flow model fits well with the experimental data in the regions of low pressure drop.Zhang correlation based on the separated flow model in microchannels show a good agreement with our experiment,but has higher values than the experimental data.According to the regular relation between the parameter C and parameter X,the modified correction of Chisholm C method was given by considering liquid Reynolds number(Re_(L))and Bond number(Bo),and it fits well with the experimental data.