摘要
为了研究边界滑移对上游泵送机械密封性能的影响,建立液膜三维几何模型和计算模型,基于Navier线性滑移模型对液膜壁面边界条件进行修正,采用商用软件Fluent的SIMPLEC算法及层流模型求解三维Navier-Stokes方程,并分析相对滑移量对液膜静压分布、开启力、摩擦扭矩、泄漏量的影响规律.结果表明:相对于边界滑移发生的位置,滑移速度的大小对密封性能的影响更大;当相对滑移量较小时,存在边界滑移与无滑移的模拟结果无明显区别,能很好地解释宏观无滑移边界假设的应用,当相对滑移量较大时液膜动压效应随滑移的增加而减弱,开启力、摩擦扭矩、泄漏量都随边界滑移的增加而减小;相对于开启力的降低,边界滑移的减阻和降低泄漏的效果更为明显;当开启力较小,应避免边界滑移发生;当开启力足够大时,加工成超疏水表面形成边界滑移,可极大地减少摩擦扭矩,降低能耗.
To study effects of boundary slip on performance of upstream pumping mechanical seal,the geometric and computational models of fluid film are built.The Navier-Stokes equations of the fluid film flow are solved in Fluent by employing SIMPLEC algorithm and finite volume method.The boundary conditions are modified with the Navier linear slip model and the effects of boundary slip on the film pressure distribution,opening force,friction torque and fluid leakage are analyzed.The results show that the slip velocity has a greater influence than the location of slip occurrence.When the slip velocity is tinier,the results of simulation are almost the same as the data without slip,indicating the non-slip assumption for macro flow of a fluid is reasonable.However,when the slip is larger,the dy-namic effect of fluid film is weakened and the opening force,friction torque and fluid leakage are decreased with the increasing slip velocity.Additionally,the reduction in both friction torque and leakage is more significant than that in opening force.If the opening force is smaller,the boundary slip shouldBe avoided.If the opening force is large enough,the boundaries shouldBe made super hydrophobic to introduce boundary slip effect so as to reduce the friction torque,eventually to save energy consumption.The results are useful to the design of an upstream pumping mechanical seal.
出处
《排灌机械工程学报》
EI
CSCD
北大核心
2015年第1期55-60,共6页
Journal of Drainage and Irrigation Machinery Engineering
基金
国家自然科学基金资助项目(51279067)
航空科学基金资助项目(201328R3001)
关键词
上游泵送
机械密封
边界滑移
开启力
摩擦扭矩
upstream pumping
mechanical seals
boundary slip
opening force
friction torque
