密闭容器漏热液氢饱和过程分析

Analysison saturation process of liquid hydrogen with heat leakage in closed container

结合在氢氧火箭发动机及箭体组件试验过程中遇到实际情况,提出了液氢介质在密闭容器内饱和过程状态变化的问题,该问题的分析结果可以用于试验过程的安全评估。首先利用质量和能量守恒方程,对密闭容器内氢介质的饱和状态过程建立了数学模型;根据模型的数学解析结果对饱和过程进行了定性分析,提出了临界充满率的概念,发现了饱和状态过程可以分成完全汽化、完全液化、中间饱和平衡等不同的过程。然后结合一个典型的液氢试验的工程实例,利用数学模型对饱和过程的状态参数进行了计算,计算结果与定性分析非常吻合。最后总结了密闭容器内液氢的饱和状态过程的规律,指出液氢充满率低时液氢可以完全汽化、充满率高时液氢可以膨胀至完全充满;同时指出,对于试验导管90%的充满率下,液氢将膨胀并充满试验腔,容易出现超压破坏风险。

The state variation of the saturation process for the liquid hydrogen in a closed container is presented according to the practical problem in the tests of a hydrogen-oxygen rocket engine and its components. The analysis results of this problem can be used for the safety assessment of the test process. In this paper,the mass and energy conservation equations are used to establish a mathematic model for the saturated condition of hydrogen medium in the closed container. The saturation process is qualitatively analyzed according to the mathematical analysis results of the model,and the conception of critical filling rate is proposed creatively. It is found that the saturation state process can be divided into different processes of complete vaporization,complete liquidation and intermediate saturation equilibrium. Combined with a typical engineering case of liquid hydrogen test,the state parameters of the saturation process are calculated by means of the mathematic model. The calculated results are in good agreementwith the qualitative analysis. The rule of the saturation process of liquid hydrogen in the closed container is summarized. It is indicated that the liquid hydrogen can be completely vaporized when the filling rate of liquid hydrogen is low,and the liquid hydrogen can be fully expanded when the filling rate is high. In addition,the liquid hydrogen will expand and completely fill the test duct when the filling rate of test duct is 90%,which is easy to cause an overpressure damage risk.