涂层表面上湿热空气对流冷凝传热的实验研究

Experimental Investigation on Coating Surface on the Convection-condensation Heat Transfer of Hot Humidity Air

采用加湿热空气模拟燃气锅炉的尾部烟气,通过热管换热器进行对流冷凝传热实验研究;并利用十八烷基硫醇形成的分子自组装膜对热管表面进行改性,从而强化冷凝传热。实验在较大的加湿热空气温度(70～120℃)和水蒸气体积分数(0%～20%)范围内进行,主要研究了对流冷凝传热的影响因素和分子自组装膜的强化效果。实验结果表明:水蒸气体积分数、加湿热空气的质量流量和入口温度是影响对流冷凝传热的主要因素,拥有分子自组装膜的改性表面对冷凝传热有极好的强化作用。

A modified surface of heat pipe was prepared with n-octadecyl mercaptan self-assembled monolayers （SAMs）. In order to investigate the characteristics of convection-condensation heat transfer of the heat pipe heat exchanger and heat transfer enhancement after modification, vapor-air mixture generated by a boiler was used to simulate the flue gas experimentally. The experiment focused on factors that may affect the performance of the convectioncondensation heat transfer and the efficiency of heat transfer enhancement in the presence of SAMs. The experiment was conducted under the condition of temperature ranged from 70 ℃ to 120 ℃ and of vapor volume fraction ranged from 0 to 20%. The results are shown below： the vapor volume fraction, the mass flow rate and the inlet temperature of the vapor-air mixture are the main factors that influence the performance of the convection-condensation heat transfer; the surface of heat pipe modified with SAMs has a great effect on the enhancement of heat transfer.