基于逾渗理论的液体火箭发动机管路接头密封性能研究  

Research on Sealing Performance of Pipe Joint of Liquid Rocket Engine Based on Percolation Theory

作　　者：金辉 赵有磊 尚现伟 金平[1] 蔡国飙[1] JIN Hui;ZHAO You-lei;SHANG Xian-wei;JIN Ping;CAI Guo-biao(School of Astronautics,Beijing University,Beijing 102206,China;Beijing Aerospace Propulsion Institute,Beijing 100076,China)

机构地区：[1]北京航空航天大学宇航学院,北京102206 [2]北京航天动力研究所,北京100076

出　　处：《强度与环境》2022年第6期1-10,共10页Structure & Environment Engineering

摘　　要：液体火箭发动机管路接头发生密封失效将给发动机带来巨大的安全隐患,深入认识管路接头的密封区域形成机理和建立密封性能的评价方法,有助于提高发动机工作的可靠性。构建微尺度下具有Gauss分布特征的粗糙面有限元接触模型,基于逾渗理论寻找临界接触压力这一密封性能评价指标的具体数值。以37°的DN6球形管路接头为研究对象,建立宏观尺度有限元接触模型,分析预紧力、介质压力和材料搭配对接头密封性能的影响。结果表明:表面粗糙度将增大粗糙面的高度差,自相长度可增加粗糙表面的连续性。临界接触压力为520MPa,应用该指标评价密封性能和45MPa高压气密试验得到的结果相吻合。在接头的拧紧过程中,接头密封性能与预紧力呈线性关系,并且存在满足密封性能的最小预紧力。在预紧力不变的条件下,接头只能承受一定范围内的介质压力。不同屈服强度的材料搭配有助于提高管路接头的密封性能。The sealing failure of pipe joint of liquid rocket engines will bring huge potential safety hazards to the engine.A deep understanding of the formation mechanism of the sealing area of pipe joint and the establishment of evaluation methods for sealing performance will help improve the reliability of the engine.A rough surface finite element contact model with Gauss distribution characteristics at the microscale is constructed,and the specific value of the critical contact pressure,the sealing performance evaluation index,is found based on the percolation theory.Taking the 37°DN6 sphere pipe joint as the research object,a macro-scale finite element contact model was established to analyze the influence of tightening force,medium pressure and material matching on the sealing performance of the joint.The results show that the surface roughness will increase the height difference of the rough surface,and the autocorrelation length can increase the continuity of the rough surface.The critical contact pressure is 520MPa,and the application of this index to evaluate the sealing performance is consistent with the results obtained from the 45MPa high-pressure test.During the assembly process of the joint,the sealing performance of the joint has a linear relationship with the tightening force,and there is a minimum tightening force that meets the sealing performance.Under the condition of constant preload,the joint can only withstand medium pressure within a certain range.The combination of materials with different yield strengths helps to improve the sealing performance of the pipe joint.

关 键 词：液体火箭发动机管路接头 密封性能 粗糙面 逾渗理论 临界接触压力 

分 类 号：V431[航空宇航科学与技术—航空宇航推进理论与工程]