环境压力对低温容器蒸发流量的理论分析和试验验证

Theoretical and experimental investigation of atmospheric pressure on mass flow rate for cryogenic vessel during boil-off

建立了用于计算低温容器蒸发流量的数学模型,得出了蒸发流量与环境温度、环境压力之间的关系。结果显示,瞬时蒸发流量变化不但受到环境压力影响,同时还受到环境压力变化率以及容器内液体量的影响。提出了衡量环境压力变化对蒸发流量影响程度的无因次量,讨论了在不同漏热、不同装载量情况下环境压力变化的影响程度。以液氮为工质,对35立方米高真空多层绝热低温容器在不同地点进行了试验,试验结果与计算结果符合较好。

A thermodynamic model describing the mass flow rate of high-vacuum-multilayer-insulation cryogenic vessel during boil-off was developed.The dependence of the transient mass flow rate on atmospheric temperature and pressure was revealed.The results showed that the transient mass flow rate during boil-off depends not only on the atmospheric pressure,but also on the change rate of atmospheric pressure and the mass inventory in the vessel.A dimensionless parameter evaluating the importance of the effect of pressure variation relative to the mass flow with different heat leak and fill-rate,respectively,was provided.Finally,the boil-off experiments using liquid nitrogen in a 35 cubic meters with high-vacuum multilayer-insulation in different locations were conducted,verification according to the comparison between evaluated calculations and measured quantities was made.