强制对流深冷翅片管表面霜层生长行为研究

Study on frosting behavior of cryogenic finned tube under forced-draft conditions

耦合欧拉模型和相变传质速率模型,建立强制对流深冷工况下空浴式翅片管表面霜层生长的热质传递模型,利用CFD模拟研究强制对流深冷翅片管表面霜层生长行为,分析空气流速、空气温度、空气相对湿度对翅片管表面结霜的影响。结果表明:对于翅片管表面温度143 K的深冷工况下,常温湿空气强制横掠深冷翅片管时,迎风面翅片上的霜层生长速率大于背风面。结霜60分钟时,空气流速每提高1 m/s,则翅片管表面霜层平均厚度增加12.8%;空气温度每提高5 K,则翅片管表面霜层平均厚度减少5.47%;空气相对湿度每提高20%,则翅片管表面平均霜层厚度增加18.63%。

A heat and mass transfer model based on coupling Euler model and phase change mass transfer model was developed to study the cryogenic frosting mechanism on an air-based finned tube under forced convection.The frosting behavior on the finned tube surface under forced-draft conditions was investigated numerically by using the CFD method.The effects of air velocity,temperature and relative humidity on the frosting behavior were analyzed,respectively.The results show that under the cryogenic condition that the surface temperature of finned tube is 143 K,the frost growth rate on the windward side of the tube is greater than that on the leeward side when the cold air is forced to cross the cryogenic finned tube.In the case of frosting for 60 minutes,the frost layer thickness is increased by 12.8%on average with a 1 m/s increasement in the air velocity,by 5.47%with a decrease of 5 K on the air temperature and by 18.63%with 20%of increasement in the relative humidity of air,respectively.