水平新型微肋管内流动冷凝换热及流阻特性

Flow condensation heat transfer and pressure drop in horizontal micro-fin tubes

为研究微肋管结构尺寸及工况等对管内流动冷凝性能的影响,采用R22为工质对4种结构的微肋管和1根f 9.52 mm光管进行了实验. 根据实验结果分析了质量流速、微肋结构尺寸和管径等对冷凝换热性能的影响. 实验结果表明,两根f 9.52 mm微肋管的换热系数分别比光管提高了90% 和120%,而其内表面积只比光管增加了40% 和70%.

To investigate the effects of micro-fin geometries and operating conditions on flow condensation performance of micro-fin tubes, tests were conducted on four micro-fin tubes having different micro-fin geometries and one smooth tube having 9.52 mm outside diameter (OD). Two of the micro-fin tubes have 9.52 mm OD and the other two have 7.0 mm OD. The refrigerant used is R22. The experiments were carried out for 90~400 kg/(m2·s) refrigerant mass fluxes at 45℃ condensation temperature, 30~45℃ inlet superheat degrees, 3℃ outlet sub-cooling degrees. The variations of condensation performance of micro-fin tubes with refrigerant mass flux are obtained. The effects of micro-fin geometries and tube diameter on the performance are discussed. The two 9.52 mm OD micro-fin tubes yield 90% and 120% greater heat transfer coefficients than the smooth tube, while the inside surface areas of the two micro-fin tubes are only 40% and 70% greater than that of the smooth tube.