斜翅型冷凝强化换热管传热性能的实验研究

对一种斜翅型外翅片带内螺纹的冷凝强化换热管进行传热性能的实验研究。管外冷凝换热的制冷剂为R134a,管内对流换热的介质为水。分别在定热流密度与定水流速的条件下进行一系列工况的实验,得到相应的实验数据。在定热流密度条件下,利用Wilson图解法得到管内的换热系数数据及相应的计算关联式。在定水流速的条件下,利用分离方法得到管外冷凝换热系数数据及相应的计算关联式。将强化管换热系数数据与光管换热系数的理论计算值进行了比较,结果表明:冷凝强化换热管管内对流换热的强化倍率为2.4,管外凝结换热系数随壁面过冷度的增加而增大,管外凝结换热的强化倍率为:1.78～3.92。

Experimental study on characteristics of condensation heat transfer of oblique - fin tube

The experiment study was carried out on characteristics of Condensing enhanced heat transfer of a kind of oblique-fin tube with internal spiral.R134a was used as the refrigerant outside of the tube and cooling water was used as the medium inside of the tube.The experimental data were obtained under the condition of constant heat flux and under the condition of constant water velocity.The inside heat transfer coefficient data and related calculated correlations were achieved by using the Wilson plot method under the condition of constant heat flux.The outside heat transfer coefficient data and related calculated correlations were achieved by using Separation method under the condition of constant water velocity.Theoretical value of heat transfer coefficient of smooth tube was compared with the experimental value of the enhanced tube.The result shows that the inside heat transfer coefficient of the enhanced tube was 2.4 times as large as that of the smooth tube;the outside heat transfer coefficient of the enhanced tube increased with the increase of the wall’s supercool;the outside heat transfer coefficient of the enhanced tube was 1.78 to 3.92 times as large as that of the smooth tube.