槽底倾斜度对螺旋槽干气密封性能的影响

摘要

An approximate analytical method for calculating the performance of dry gas seals with a tilting groove bottom structure was proposed.An analytical expression of gas film thickness at groove region was established.Based on the narrow groove theory,the pressure governing equation was solved by an approximately analytical method to obtain the pressure distribution of the seal.The opening force,leakage rate and gas film thickness were calculated and compared with those by Fluent software,and they are in good agreement with each other.The results show that the influence of the tilting groove on the sealing performance depends on the initial groove depth.Compared with the even groove bottom case,the tilting groove bottom case has smaller opening force and leakage rate when the initial groove depth is small,but larger opening force and leakage rate when the initial groove depth is large.The greater the tilting degree of groove bottom is,the larger the opening force and leakage rate are.In general,the tilting groove bottom spiral groove dry gas seal has a larger axial film stiffness,the greater the tilting degree of groove bottom,the larger the film stiffness,and the stronger the anti-interference ability.%提出一种可以计算斜底螺旋槽干气密封性能的近似解析方法.构建槽底倾斜螺旋槽干气密封的气膜厚度表达式,基于螺旋槽的窄槽理论,近似解析求解其气膜压力控制微分方程,获得槽底倾斜螺旋槽干气密封端面气膜压力分布,进而获得端面开启力、气体泄漏率和气膜刚度等密封性能,并将结果与Fluent软件计算结果进行对比,两者的结果吻合.计算结果表明:斜底槽对密封开启力和泄漏率的影响规律取决于初始槽深;与平底槽比较,当初始槽深较小时,斜底槽的开启力较小,但泄漏率也较小;当槽深较大时,斜底槽具有较大的气膜开启力,槽底倾斜程度越大,开启力越大,但同时泄漏率也越大;一般地,斜底槽具有较大的轴向气膜刚度,槽底倾斜程度越大,气膜刚度越大,抗干扰能力越强.