制冷剂在微通道扁平T型管内的气液两相流相分配特性研究

Study on phase distribution characteristics of gas-liquid two-phase flow in micro-channel flat T-junction

气液两相流在常规T型管内的相分配特性已得到充分研究,但少有文献关注微通道扁平T型管内的两相流分配特性。以两相制冷剂R134a为工质,对扁平T型管内的相分配特性进行了实验研究。实验结果表明,气液两相流在扁平T型管内的液相进口流速增加会使液相分离比减小,气相分离比增大;进口干度增加使液相分离比增大,气相分离比减小;气相进口流速对扁平T型管内泡状流的相分配影响较小。由相分配模型预测值与实验值对比可知,现有的相分配模型还无法准确预测扁平T型管内泡状流的气液相分离比。在进口干度为0.45~0.5时扁平T型管内制冷剂R134a气液相分配比较均匀。

The phase distribution characteristics of gas-liquid two-phase flow in conventional T-junction have been fully studied,but few literatures have paid attention to the distribution characteristics of two-phase flow in micro-channel flat T-junction.Using the two-phase refrigerant R134 a as the working fluid,the phase distribution characteristics in the flat T-junction are studied experimentally.The results show that the increase of the liquidphase inlet flow rate of the two-phase flow in the flat T-junction will decrease the liquid-phase separation ratio and increase the gas-phase separation ratio.The increase of the inlet quality will increase the liquid-phase separation ratio and decrease the gas-phase separation ratio.The gas inlet velocity has little effect on the phase distribution of the bubbly flow in the flat T-junction.It can be seen from the comparison between the predicted phase distribution model and the experimental value that the existing phase distribution model cannot accurately predict the gasliquid separation ratio of the bubbly flow in the flat T-junction.In the experimental conditions,when the inlet dryness is 0.45—0.5,the refrigerant R134 a in the flat T-junction has a relatively uniform gas and liquid distribution.