内外螺旋三角翅片管管外冷凝传热建模与优化(Ⅱ)——数值分析与优化

MODELING AND OPTIMIZATION OF CONDENSATION HEAT TRANSFER ON THE OUTER SURFACE OF THE VERTICAL IOSF TUBE(Ⅱ) Numerical Analysis & Optimum

为优化ＩＯＳＦ管的管外几何参数，根据所建数学物理模型，对不同换热工况和不同结构参数进行数值分析与模拟优化．研究结果表明：当管长Ｌ＝０．７ｍ、螺旋角β＝１８°、管外径Ｄｏ＝０．０１６ｍ，Ｈ＝０．００１ｍ时，φ＝７６°与Ｎ＝３２是最佳匹配参数，此时有最大平均冷凝换热系数；ＩＯＳＦ管管外螺旋角在β＜２７°的范围内，其管外传热特性与纵槽管基本相当；翅片夹角φ和螺旋槽头数Ｎ是对ＩＯＳＦ管管外冷凝换热产生主要影响的结构参数；局部冷凝换热系数沿管长跌落主要集中在开始的０．５ｍ内，因此排液盘的间距应不大于０．５ｍ。

In order to optimize geometric parameters of tube wall outside the IOSF tube, numerical analysis and simulation optimum for some different structure parameters under different heat transfer working conditions have been investigated according to the developed mathematical physical model. The simulation results show that when the length L is 0.7 m, the spiral angle β is 18°, the outer diameter D 0 is 0.016 m and the height H is 0.001 m, 76° for the φ and 32 for the N are the optimum parameters. In such a case, the maximum value of condensation heat transfer coefficient can be obtained, and the heat transfer ability of the IOSF tube with the spiral angle of fins on the outer side β <27° is almost equal to the vertical grooved tube. The angle φ of the groove among the fins and the starts N of the fins are the main parameters that play an important role in the condensation. The decrease in the local condensation heat transfer coefficient is mainly stated at the range of 0.5 m in the longitudinal direction of the tube. So the distance of the drainage panels for enhancing the average condensation heat transfer coefficient should not exceed 0.5 m.