Experimental study on condensation heat transfer of R32, R152a and R22 in horizontal minichannels
Experimental study on condensation heat transfer of R32, R152a and R22 in horizontal minichannels
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DOI：
10.1016/j.applthermaleng.2015.07.062
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发表时间：
2015-11
影响因子：
6.4
通讯作者：
Na Liu;Junming Li
中科院分区：
文献类型：
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作者：
Na Liu;Junming Li
对R32、R152 a和R22在圆形（dh= 1.152 mm）和方形（dh= 0.952和1.304 mm）水平微通道内的凝结换热特性进行了实验研究。实验使用的饱和温度为30 °C至50 °C，质量通量为200至800 kg/（m2 s），蒸汽质量为0.1至0.9。实验研究了流动条件（质量流量、蒸汽干度、饱和温度和冷却剂入口温度）、通道直径、通道几何形状和热物理性质对传热系数的影响。结果表明，换热系数随质量流量和干度的增大而增大，随饱和温度和通道直径的减小而减小。冷却剂入口温度对实验结果影响不大。当蒸汽干度小于0.5时，方形通道内的换热系数比圆形通道内的换热系数高。研究表明，从凝结换热特性来看，R32和R152 a是R22的良好替代物。冷凝传热关联式和理论解被用来预测在这项研究中的实验数据。
The heat transfer characteristics of R32, R152a and R22 during condensation were experimentally investigated in a circular (dh= 1.152 mm) and two square (dh= 0.952 and 1.304 mm) horizontal minichannels. The experiments used saturation temperatures from 30 °C to 50 °C, mass fluxes from 200 to 800 kg/(m2s) and vapor qualities from 0.1 to 0.9. The experiments investigated the effects of the flow conditions (mass flux, vapor quality, saturation temperature and coolant inlet temperature), the channel diameter, the channel geometry and the thermophysical properties on the heat transfer coefficients. The results show that the heat transfer coefficients increase with increasing mass flux and vapor quality and decreasing saturation temperature and channel diameter. The coolant inlet temperature has little effect on the experimental results. The heat transfer coefficients in the square minichannel are enhanced by the surface tension for vapor qualities less than 0.5 compared with that in the circular minichannel. The study shows that R32 and R152a are good substitutes for R22 based on the condensation heat transfer characteristics. Condensation heat transfer correlations and a theoretical solution are used to predict the experimental data in this study.