液氧煤油发动机碟形金属密封特性

Sealing characteristic of dish-shaped metal seal in LOX/kerosene rocket engine

碟形金属密封是一种精密的封闭式密封结构,在预紧过程和工作过程中表现出强烈的非线性特征,采用试验手段或者线性有限元方法无法对其密封特性进行直观量化研究。为了解决该问题,以1200kN推力液氧煤油发动机中的一种小直径碟形金属密封结构为研究对象,采用非线性弹塑性有限元仿真计算方法,分析了密封结构轴向压缩量、各密封面的密封面积及密封应力随加载载荷的变化规律,研究了碟形密封结构的密封机理和轴向刚度特性。分析结果表明:预紧载荷作用后4个密封面均形成密封面积和密封应力,预紧状态下碟形环发生“S”形变形并出现失稳现象,介质的压力载荷和温度载荷造成各密封面的密封性能下降。

Dish-shaped metal seal is a kind of precise and closed sealing structure,which shows strong non-linear characteristics during the pre-tightening process and working process.It is impossible to quantify its sealing characteristics intuitively by means of experiment or linear finite element method.In order to solve this problem,a small-diameter dish-shaped metal seal in the LOX/kerosene rocket engine with 1 200 kN thrust level was studied in this paper.By conducting the nonlinear elastic-plastic finite element analysis,the compression quantity of sealing structure,the variation regularity of sealing area and sealing stress with loading load were analyzed.Furthermore,the sealing mechanisms and axial rigidity characteristic of the sealing structure were studied.The analysis results show that the sealing area and stress are formed on the four sealing surfaces after preloading.Under the preloading condition,the dish-shaped ring undergoes “S” deformation and the unstable phenomenon occurs.The pressure and temperature loads of the medium cause the decrease of sealing performance on each sealing surface.