液体火箭发动机低温阀门铝垫片密封性能数值分析

Numerical Analysis on Sealing Performance of Aluminum Gasket for Cryogenic Valve of Liquid Rocket Engine

关键词:  液体火箭发动机  低温阀门  密封垫片  接触压力  温度载荷

Key words:  Liquid rocket engine  Cryogenic valve  Sealing gasket  Contact pressure  Temperature load

摘要:

为研究液体火箭发动机低温阀门铝垫片密封结构在低温工作环境下的密封性能，利用ABAQUS软件建立了该结构的二维轴对称模型，计算了低温工作状态下铝垫片密封表面接触压力的变化，并研究了铝垫片在循环温度载荷作用下接触压力下降的机理。结果表明，在低温工作时，密封垫片与阀门各部件材料线胀系数不同，导致在温度降低时密封面上接触力下降；而铝垫片密封表面上复杂的应力应变状态导致接触压力在温度载荷作用下无法恢复。在温度载荷循环作用下，铝垫片密封面上产生了棘轮效应。垫片的塑性应变在棘轮效应中累积，且最大应力值在棘轮效应中下降；接触力会随着温度载荷循环次数增加逐步降低并在一定周期后保持稳定。提出了采用锥形垫片的结构改进方案，并通过仿真验证了该结构在循环温度载荷作用下保持密封压力的有效性。

Abstract:

In order to study the sealing performance of aluminum gasket sealing structure for cryogenic valve of a liquid rocket engine under low temperature environment， a two-dimensional axisymmetric model of the sealing structure was established by ABAQUS software. Contact pressure of aluminum gasket seal surface under low temperature working condition was calculated， and the mechanism of contact pressure drop of aluminum gasket under cyclic temperature load was studied. The results show that the contact pressure on the sealing surface decreases at low temperature due to the different linear expansion coefficient between the sealing gasket and various parts of the valve， while the complex stress-strain state on the sealing surface of aluminum gasket leads to the failure of contact pressure recovery under temperature load. The ratchet effect is produced on the sealing surface of aluminum gasket under the cyclic temperature load. The plastic strain of the gasket accumulates in the ratcheting effect， and the maximum stress decreases in the ratcheting effect. The contact force decreases gradually with the increase of temperature recycle times， and remains stable after a few period. In addition， an improved structure of sealing gasket by using conical gasket is proposed， and the effectiveness of the structure to maintain the sealing pressure under the cyclic temperature load is verified by simulation.