制冷剂种类与翅片管换热器管径的匹配特性
Matching Characteristics of Refrigerant Species and Tube Diameters of Heat Exchanger

针对空调用翅片管换热器，本文研究了4种制冷剂在管内的流动阻力及表面传热系数随换热器管径的变化，并通过模拟计算给出了不同制冷剂所对应的最佳换热器管径。并根据实际空调器系统确定相关参数，计算得到管内流动阻力损失从大到小排列依次为：R22、R290、R410A、R32，表面传热系数从大到小排列依次为R32、R410A、R290、R22。在空调器制冷工况，满足换热量需求的条件下，冷凝器的入口压力（压缩机排气压力）越低，系统的效率越高；根据模拟计算，换热量为2 000 W时，随着换热器管径的增大，不同制冷剂所对应的冷凝器入口压力先降后增，得到R22最适宜的换热器管径为7~7.5 mm，R410A与R32为6~6.5 mm，R290为6.5~7 mm。
This study investigates the flow resistance and surface coefficient of the heat transfer of four types of refrigerant with different tube diameters for a finned-tube heat exchanger. The optimum tube diameter for each refrigerant was studied using a developed simulation model. The simulation results show that the flow resistance characteristics of the four refrigerants followed the order of R22 > R290 > R410A > R32, and the comparison of the surface coefficient of the heat transfer followed the opposite trend. For an air conditioner, the system coefficient is known to increase with the decrease in the condenser inlet pressure (compressor exhaust pressure) under a fixed cooling capacity. According to the simulation results, the condenser inlet pressure first decreased and then increased with the increase in the tube diameter of the heat exchanger when the heat transfer capacity was set to 2 000 W. The optimum diameters of the heat exchanger for R22, R410A, R32, and R290 followed the sequences of 7–7.5 mm, 6–6.5 mm, 6–6.5 mm, and 6.5–7 mm