R134a在多孔扁管内沸腾换热试验研究

Experimental Study on Boiling Heat Transfer of R134a in Multi-port Extruded Tube

采用试验的方法对制冷剂R134a在多孔扁管内的沸腾换热特性进行研究，搭建沸腾换热试验系统，以R134a为工质对当量直径为0．63mm的多孔扁管的沸腾换热特性进行研究，试验中质量流率范围为116．5～466．0kg·m^-2·s^-1，热流密度范围为13～52．7kW／m^2。试验结果与适用于微小尺寸通道的沸腾换热公式的计算值对比可知，沸腾换热系数试验值与Bertsch公式计算值吻合度较高，且只在大质量流率时，试验值才与Cooper公式和LiuandWinterton公式计算值接近。

The boiling heat transfer characteristics of a multi-port extruded tube are experimentally inves- tigated. To test the boiling heat transfer characteristics of the tube in equivalent diameter 0.63 ram, a boiling heat transfer test system with refrigerant R134a is built as the working medium. Tests are per- formed witha mass flux of 116.5-466.0 kg·m^-2·s^-1 anda heat flux of 13--52.7 kW/m^2. The ex- perimental results are compared with the calculation results of the formulas that suit for boiling heat transfer in small size channel. It shows that the experimental data of boiling heat transfer coefficient fit well with the calculations of Bertsch correlation, and only in the big mass flux, the data are close to the calculations of the Cooper correlation and Liu and Winterton correlation.