采用不同辐射换热模型对液氦传输管线的数值研究

Numerical simulation on the thermal characteristics of LHe transfer lines by using different radiation models

低温传输管线是大型低温制冷设备中的关键部件之一,采用高真空多层绝热方式减少低温传输管线的漏热。基于Fluent计算平台,分别采用DTRM模型、P1模型、ROSSELAND模型、DO模型、S2S模型对真空环境下的液氦传输管线进行了数值模拟。对比解析计算解,确定了适合液氦低温管真空环境下辐射换热的计算模型,并利用S2S模型对低温传输管线的整体结构进行了模拟。模拟分析表明:S2S模型计算得到的管壁面辐射和温度场与解析解较为接近,更适合真空环境下的壁面辐射换热计算;支撑漏热为主要漏热,管壁面间辐射换热占总漏热量比例较小,整体漏热小于1W/m,满足设计需求。

The cryogenic transfer lines are critical components in the large cryogenic refrigeration equipment. Multi -layer in- sulation is used to reduce heat leak in the lines DTRM model, P1 model, ROSSELAND model and DO model were employed to simulate the temperature field of the LHe transfer line in the protection of vacuum environment. Comparison results show that re- sult obtained by $2S model is most reasonable. So the numerical simulation of the LHe transfer was obtained. The results show that the radiation of wall and the temperature field of support and multi - layer insulation agree well with the theoretical predications using S2S model. The heat leak of support accounts for the main factors. While the heat leak of wall radiation is a small proportion. The heat leak of tube is less than 1W/m,which satisfies the requirement of design.