斯特林机帽式密封性能分析及回归参数优化设计

Analysis of Cap-sealing Performance of Stirling Engine and Optimization Design of Regression Parameter

为改善斯特林机活塞杆帽式密封性能,首先采用数值仿真分析了5 MPa工质压力下其静、动态力学特性,从而获取了O型圈内径尺寸L_(N)、C型环径向壁厚T和装配过盈量S这3个关键结构参数对密封性能的影响规律。在此基础上,利用回归设计法以配伍面最大接触压力平稳且密封可靠为优化目标,对密封结构的上述3个关键参数进行优化设计以确定其最佳匹配方案,最后通过密封试验台验证了本文优化设计方法的准确性和普适性。结果表明:活塞杆与C型环密封面中间区域上最大接触压力随L_(N)和S的增大而增大,但随T的增大而减小;通过估计回归系数和方差分析(ANOVA)发现,L_(N)对密封性能影响最为显著、S次之、T影响最小;L_(N)和T、L_(N)和S交互项对响应显著,而T和S交互项对响应不显著;当L_(N)为13.745 mm、T为0.40 mm和S为0.020 mm时,优化密封件对应的正行程最大接触压力为9.01 MPa、回程为9.75 MPa,较工程在用密封件(L_(N)=13.780 mm、T=0.50 mm、S=0 mm)最大接触压力分别降低了14.7%和25.5%。实验进一步验证了优化密封件的密封性能和使用寿命均优于工程在用密封件,并且在不同工质压力下优化密封件的接触压力均匀性更好,减摩延寿效果显著,充分证明本文性能分析与优化设计方法准确有效。

To improve the performance of the piston rod cap seal of Stirling engine,the initial step involves analyzing the static and dynamic mechanical characteristics under a 5 MPa operating pressure through numerical simulation,aiming to elucidate the governing factors.This analys-is helps identify the impact of three critical structural parameters on the sealing performance:the O-ring inner diameter(L_(N)),the C-ring radial wall thickness(T),and the assembly interference(S).Therefore,the regression design method is employed to optimize these parameters to achieve the best solution that ensures a smooth and reliable seal with maximum contact pressure on the mating surface.The optimization method's accuracy and universality are subsequently confirmed using a seal test bench.The findings indicate that the maximum contact pressure on the piston rod and C-ring’s middle sealing surface increases with L_(N)and S but decreases with T.The regression analysis and ANOVArevealed that L_(N)signific-antly influences sealing performance,followed by S,while T has the least impact.Significant interaction effects are observed between L_(N)and T and L_(N)and S,whereas the interactions between T and S are insignificant.At L_(N)of 13.745 mm,T of 0.40 mm,and S of 0.020 mm,the optimized seal exhibits a maximum contact pressure of 9.01 MPa during forward travel and 9.75 MPa during return travel.These pressures are 14.7%and 25.5%lower,respectively,compared to the seals currently used in the project(L_(N)=13.78 mm,T=0.5 mm,S=0 mm).The experiments further veri-fy that the optimized seal outperforms the current engineering seals regarding sealing performance and service life.In addition,the optimized seal demonstrates improved contact pressure uniformity under varying operating pressures,significantly reducing friction and extending service life.These results validate the effectiveness of the performance analysis and optimization design method discussed in this study.