水平微肋管内流动蒸发换热特性的实验研究

为了研究微肋管结构尺寸及工况等对管内流动蒸发性能的影响，对4种微肋管和1根9.52 mm光管进行了实验，4根微肋管中管外径为9.52 mm和7 mm的各2根，所用工质为R22.实验中质量流速变化范围为90～400kg•m^-2•s^-1，所选工况为：蒸发温度7℃，入口干度15%～20%，出口过热度5～6℃.获得了蒸发换热性能随质量流速的变化，讨论了微肋结构尺寸和管径等对蒸发换热性能的影响.两根9.52mm微肋管的传热系数比光管分别分别提高了130%和180%，而其内表面积只比光管分别增加了40%和70%.

FLOW EVAPORATION HEAT TRANSFER AND PRESSURE DROP IN HORIZONTAL MICRO-FIN TUBES

To investigate the effects of micro-fin geometry and operating conditions on flow evaporation performance of micro-fin tubes, tests were conducted on four micro-fin tubes having different micro-fin geometries and one smooth tube having 9.52mm outside diameter (OD). Two of the micro-fin tubes had 9.52mm OD and the remaining two had 7.0mm OD.The refrigerant used was R22. The experiments were carried out for 90—400kg•m^-2•s^-1 refrigerant mass fluxes at 7℃ evaporation temperature, 15%—20% inlet vapor quality, 5—6℃ outlet superheat degrees. The variations of evaporation performance of micro-fin tubes with refrigerant mass flux were obtained. The effects of micro-fin geometry and tube diameter on performance were discussed. The two 9.52mm OD micro-fin tubes yielded 130% and 180% greater heat transfer coefficients than the smooth tube, while the inside surface areas of the two micro-fin tubes were only 40% and 70% greater than that of the smooth tube.