一种冷凝强化换热管传热性能的试验研究

Experimental Study on Heat Transfer on an Enhanced Condensation Tube

以目前广泛使用的R22为工质,对一种冷凝强化换热管管外冷凝换热性能进行了实验研究。管内以乙二醇为冷却介质。在恒定热流密度、变乙二醇流速与乙二醇流速不变条件下,改变乙二醇进口温度得到一系列实验数据,再通过威尔逊(Wilson)图解法同时得到管内外换热关联式。给出了不同管内流速时管外冷凝换热性能对比图。该冷凝强化换热管管外冷凝换热性能与普通光管相比,传热强化倍率为4.48。由于管内表面有细微的凹凸形状,使管内对流换热系数达到光滑管的1.33倍。

The experiment on condensation heat transfer outside an enhanced tube was conducted. Glycol was applied to be the cooling medium in the tube and R22 was adopted to be the refrigerant in the experiment. The experimental data were obtained by changing the inlet temperature of glycol under the condition of constant heat flux, constant glycol flow rate or different glycol flow rate. The inside and outside heat transfer coefficient correlations were achieved by the Wilson Plot method. The outside heat transfer coefficient of the enhanced tube was 4.48 times as large as that of a smooth tube. In addition, the inside heat transfer coefficient was 1.33 times as large as that of the smooth tube because of the inner surface with a small convex shape.