冷凝面形状影响含空气蒸汽冷凝特性数值分析

Numerical analysis of the effect of condensation shape on steam-air condensation characteristics

为评估蒸汽在不同形状壁面的冷凝特性,本文基于不同壁面(单管、平板、圆柱、球形)在压力为0.1~1.6 MPa、空气质量分数为0.1~0.9、过冷度为10~80℃的参数范围,开展了含空气蒸汽冷凝数值分析。结果表明:冷凝面形状对蒸汽冷凝特性有显著影响,主要可分为曲率效应和结构效应的影响。基于2种效应提出了曲率强化因子和结构强化因子,发现曲率强化因子与压力、过冷度呈负相关关系,与空气质量分数呈正相关关系;结构强化因子与压力、过冷度、空气质量分数均呈正相关关系。曲率效应引发的强化效果最大可达16%,结构效应引发的强化作用最大可达32%。此外,单管换热性能最佳,圆柱与平板其次,球形面换热性能最低。

To evaluate the condensation heat transfer characteristics of steam for various condensation wall,the present work conducted numerical simulations based on various wall(single tube,plate,cylinder,spherical)in the parameter range of pressure from 0.1 to 1.6 MPa,air mass fraction from 0.1 to 0.9 and sub-cooling from 10 to 80℃.The results indicate that the condensation shape has an obvious effect on the condensation characteristics.It can be mainly divided into the curvature effect and the structure effect.Based on the two effects,the curvature enhancement factor and the structure enhancement factor are proposed.The curvature enhancement factor has a negative correlation with pressure and subcooling,and a positive correlation with air mass fraction.The structure enhancement factor is positively correlated with pressure,subcooling,and air mass fraction.The maximum enhancement effect caused by the curvature effect can reach 16%,and the maximum enhancement effect caused by the structure effect can reach 32%.In addition,the heat transfer performance of the single tube is optimal,followed by cylinder and plate,and the heat transfer performance of the spherical surface is the worst.