R134a在微通道内的流动沸腾两相压降特性研究

Study on Pressure Drop Characteristics of Two-phase Flow Boiling of R134a in Microchannel

通过实验研究了制冷剂R134a在两种微通道尺寸下(0.5 mm和1 mm)的两相压降特性。其中,质量通量G范围为500~2500 kg/(m2·s),热通量q范围为15~147 kW/m2,饱和温度Tsat范围为15~37℃。研究评估了5种已有压降模型,与实验数据进行了比较。结果表明,摩擦压力梯度随干度的升高呈现出先增大后减小的趋势。其中,1 mm管实验结果与Kim和Mudawar的模型吻合较好,但0.5 mm管预测值高于实验值。相比于1 mm管,0.5 mm管压力波动较大,并导致压降数值分布更分散。

The two-phase pressure drop characteristics of R134a were studied experimentally.The experimental data cover two types of channels(inner diameter:0.5mm and 1mm)with G from 500 to 2500 kg/(m2·s),q from 15 to 147 kW/m2,and Tsat from 15 to 37℃.Five existing pressure drop models were evaluated,and the predicted results were compared with experimental data.The results show that the gradient of friction pressure drop presents a trend of increasing firstly and then decreasing with the vapor quality.The results of the 1 mm tube are in good agreement with the model of Kim and Mudawar,but the pressure drops of 0.5 mm tube are overestimated by the model.Compared with the 1 mm tube,the pressure fluctuation of the 0.5 mm tube is larger,and the pressure drop value distribution is more dispersed.