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在内径为2 mm的水平不锈钢微通道内对制冷剂R290的沸腾换热特性进行了实验研究。实验工况为:制冷剂质量流率分别为150和330 kg/(m~2·s),测试段热流密度分别为43和76 k W/m~2,制冷剂干度的范围为0.1-0.7,测试段制冷剂的饱和温度为15和26℃,测试段制冷剂的入口干度范围为0-0.65。在相同干度情况下,将制冷剂进入测试段前未进行预热而获得的换热系数与制冷剂进入测试段前进行预热后获得的换热系数进行了对比。研究结果表明:制冷剂进入测试段前进行预热会使换热系数产生偏差,偏差的平均值达到了14.2%;在实验范围内,随着制冷剂在测试段入口以及制冷剂在测试段内干度的上升,预热所引起的换热系数偏差将逐步下降。
In a horizontal stainless steel microchannel with inner diameter of 2 mm, the boiling heat transfer characteristics of refrigerant R290 were experimentally studied. The experimental conditions were as follows: the mass flow rates of the refrigerant were 150 and 330 kg / (m ~ 2 · s) respectively, the heat flux density in the test section was 43 and 76 kW / m ~ 2 respectively, and the range of refrigerant dryness was 0.1- 0.7, the saturation temperature of the refrigerant in the test section is 15 and 26 ℃, and the inlet dryness of the refrigerant in the test section ranges from 0 to 0.65. Under the same dry condition, the heat transfer coefficient obtained without the preheating of the refrigerant before entering the test section is compared with the heat exchange coefficient obtained after the refrigerant is preheated before entering the test section. The results show that: the refrigerant entering the test section to preheat will make the heat transfer coefficient deviation, the average deviation reached 14.2%; within the experimental range, as the refrigerant in the test section inlet and the refrigerant in the test section Dry rise, preheating caused by heat transfer coefficient deviation will gradually decline.