微弱漏气对液氢管道插拔式法兰漏热的影响

Numerical Investigation on Heat Leak of Plug-in Flange Applied in Liquid Hydrogen Pipeline Influenced by Weak Leakage

针对低温液体输送管道中法兰是最主要漏热源的问题,提出在法兰间隙中产生一定泄漏流量来降低低温插拔式法兰漏热量的设想,通过采用计算流体力学技术建立了三维稳态模型并对模型进行了验证。结果表明,随着泄漏流量的增大,插拔式法兰漏热量和泄漏工质出口温度降低。对于泄漏间隙在0.8~1.2mm之间的法兰,当泄漏流量小于10-5 kg/s时,增大泄漏流量会引起漏热量急剧下降;当泄漏流量大于10-5 kg/s时,泄漏流量上升会导致泄漏工质出口温度急剧降低,且通过增加法兰长度对减少法兰漏热量无作用。所以,合理控制泄漏流量可以降低低温插拔法兰的漏热损失。

Flange is a major source of heat loss in the cryogenic pipeline. A method by generating a specified leakage flux in the gap of flange is proposed to reduce the heat loss of cryogenic plug-in flange, and is verified by a 3-D steady computational model. It is found that with the increasing leakage flux, the heat loss of flange and the outlet temperature of leakage fluid are decreased. For the flange with leakage gap between 0.8 mm and 1.2 mm, as the leakage flux gets less than 10-5 kg/s, the increasing leakage flux leads to a drastic decrease of heat loss. While the leakage flux gets more than 10-5 kg/s, the outlet temperature of leakage fluid is sharply dropped with the increasing leakage flux, and increasing flange length does not affect reducing of heat loss. The heat loss of cryogenic plug-in flange can be decreased by reasonably controlling leakage flux.