R290的管内冷凝实验研究

Experimental Study on In-Tube Condensation of R290

用实验与关联式理论计算对比的方法 ,研究了自然工质丙烷在外径 9.5 2mm的铜光管、内螺纹管及内交叉肋管内的冷凝换热特性。冷凝实验的进口压力为 10 79kPa ( 30℃ )和 136 9kPa ( 4 0℃ ) ,质量流速为 10 0 ,15 0 ,2 0 0 ,2 5 0和 2 88kg m2 s,进出口状态均保持饱和状态。为获取平均局部换热系数 ,实验管段为套管式逆流换热器结构 ,分为 1m长四段 ,弯头相连。制冷剂在内管内冷凝 ,而 10 %的乙醇溶液在管间流动。实验结果与大多针对非自然工质 (CFC ,HCFC或HFC)

By a combination of experimental study and theoretical prediction, in-tube condensation tests for natural refrigerant R290 were conducted for smooth, microfin and crosshatched 9.52 mm outside diameter copper tubes. The condensation tests run at inlet pressures of 1079 kPa (30℃) and 1369 kPa (40℃) with the mass velocities of 100, 150, 200, 250 and 288 kg/m 2s. Both the inlet and outlet of refrigerant side were kept at saturated states. To measure the average local heat transfer coefficients, the test section was of counter-flow double-tube type of heat exchanger with refrigerant flowing inside the inner tube while 10 % ethanol water flowing outside. The test section was composed of four 1m-long horizontal tubes connected by three elbows. The experimental data were compared with the predicted results for in-tube evaporation and condensation heat transfer which mainly were developed for non-natural refrigerants (CFCs, HCFCs and HFCs). The condensation data are well reproduced with the existing correlations.