Abstract:

The pressure drop characteristics of refrigerant-oil mixture flow boiling inside metal-foam filled tubes were investigated experimentally. The experimental fluid is R410A/VG68 oil, and the oil concentration range is 0—5%. The structure of the metal foam used in the experiments include PPI of 5 and 10, and porosity of 95%. The experimental results show that, as the oil concentration and PPI increases, the pressure drop increases. The incomplete cells nearby tube wall decreases the flow turbulence, resulting in the decrease of pressure drop, with the decrease of tube diameter, the pressure drop in metal-foam filled tubes decreases, which is different from that in smooth or microfin tubes. Based on the experimental data, the pressure drop correlation for refrigerant-oil mixture flow boiling inside metal-foam filled tubes was developed, and it can predict the pressure drop characteristics in metal-foam filled tubes with different diameters.

Key words: metal foam, refrigerant, oil, mixture, pressure drop, two-phase flow, correlation

摘要：

实验研究了含油制冷剂在泡沫金属换热管内流动沸腾的压降特性。实验流体为R410A和VG68油的混合物,油浓度范围为0~5%;泡沫金属结构分别为5 PPI和10 PPI,孔隙率为95%。实验结果表明:随着油浓度和泡沫金属PPI的增大,压降逐渐增加;管壁附近存在不完整的泡沫金属单元,减小了流体扰动,从而导致压降减小;随着管径的减小,泡沫金属内的压降减小,此变化规律与已有常规光管或微肋管内的变化规律不同。基于实验数据开发了泡沫金属管内含油制冷剂流动沸腾的压降关联式,关联式能够预测不同管径泡沫金属内的压降特性。

关键词: 泡沫金属, 制冷剂, 油, 混合物, 压降, 两相流, 关联式