复合中空热管冷凝侧传热特性

Experimental investigation of heat transfer characteristics of condensation section in composite hollow heat pipe

复合中空热管能够有效解决普通重力热管换热设备的酸露点腐蚀问题,在回收低温烟气(<200℃)余热领域有重要的应用。建立了复合中空热管传热实验平台,对复合中空热管冷凝侧传热特性进行了实验研究。实验所用热管管长1080mm,不锈钢材质,工作介质为甲醇;热管蒸发侧和冷凝侧分别采用电加热和水冷却方式,K型热电偶被用于测量管壁温度和冷却水进出口温度,真空压力传感器测量管内蒸气饱和压力;研究了充液率(15%≤V+≤40%)和蒸发侧热流密度(9.48kW/m2≤q≤37.91kW/m2)对冷凝侧传热特性的影响。结果表明:当充液率为20%时,复合中空热管冷凝侧均温性能最好,冷凝侧换热系数最大,传热性能最佳;随着蒸发侧热流密度的增大,复合中空热管有效冷凝长度增大,冷凝侧换热系数增大。实验研究为工业应用提供了基础。

The composite hollow heat pipe can effectively solve the problem of acid dew corrosion of heat exchanger equipment comprising ordinary gravity heat pipe,and has an important application in recycling waste heat of low temperature flue gas. A heat transfer experimental platform of composite hollow heat pipe was established,and the heat transfer characteristics of condensation section were investigated experimentally. A stainless steel tube of total length of 1080mm with methanol was studied. Electrical heating was used in the evaporation section and water cooling was used in the condensation section. Wall temperatures and inlet and outlet temperatures of cooling water were measured with K type thermocouples. Vapor saturation pressure in heat pipe was measured by vacuum pressure sensor. The effect of two parameters ： filling rate （15%≤V^＋≤40%） and evaporator heat flux （9.48kW/m^2≤q≤37.91kW/m^2） on the heat transfer characteristics of condensation section were investigated. When filling rate was 20%, the composite hollow heat pipe had the maximum condensation heat transfer coefficient and showed the best isothermal characteristics of its condensation section and the best heat transfer performance. Besides,with the increase of evaporator heat flux,the effective condensation length of the composite hollow heat pipe and the condensation heat transfer coefficient increased. Experimental investigation provides a basis for industrial applications.