界面极限滑移条件下的液膜密封流场平均速度分布规律  

Average Velocity Distribution of Liquid Film Seal Flow Field under Boundary Limit Slip Conditions

作　　者：曹志康 胡琼 卢迪 肖洋 陈阳 王衍 黄茜茜 陆雨佳 CAO Zhikang;HU Qiong;LU Di;XIAO Yang;CHEN Yang;WANG Yan;HUANG Xixi;LU Yujia(School of Mechanical Engineering,Jiangsu Ocean University,Lianyungang Jiangsu 222005,China;National Key Laboratory of Science and Technology on Helicopter Transmission,Nanjing University of Aeronautics&Astronautics,Nanjing Jiangsu 210016,China)

机构地区：[1]江苏海洋大学机械工程学院,江苏连云港222005 [2]南京航空航天大学直升机传动技术重点实验室,江苏南京210016

出　　处：《润滑与密封》2023年第5期42-51,共10页Lubrication Engineering

基　　金：国家自然科学基金项目(52105187)。

摘　　要：为研究液膜密封流场平均速度分布规律,及其与流-固界面剪切应力之间的关系,基于Couette流动模型建立存在边界速度滑移时的密封间隙流场速度计算模型,采用Mixture均相模型和Schnerr-Sauer空化模型,通过数值模拟考察界面无滑移(滑移速度为0)和无剪切(滑移速度最大)2种极限情况下不同转速时液膜轴向不同位置处的微流场径向、切向和轴向速度分布,并建立流体型槽界面剪切力-速度拟合模型。研究结果显示:液膜的切向速度远大于径向和轴向速度,三维合成速度分布规律主要由切向速度决定;流场在槽区内近台阶轴向1μm范围内压力梯度发生突变,但非槽区和槽区流场相对独立,非槽区可视为简单Couette流动,槽区为逆压梯度Couette流动;流-固界面粘附剪切应力的大小与液膜边界速度滑移密切相关,槽区界面剪切应力变小时,边界滑移速度和槽内外流场各方向速度均变大,且转速越高,数值越大;在不高于10000 r/min时,空化效应对整体平均速度场的影响较小,但速度更高时,需量化空化效应,并对剪切应力-速度拟合模型进行修正。In order to study the average velocity distribution law of liquid film seal flow field and its relationship with the shear stress of liquid-solid interface,the velocity calculation model of seal gap flow field with boundary velocity slip was established based on Couette flow model.By using the mixture homogeneous model and Schnerr-Sauer cavitation model,the radial,tangential and axial velocity distributions of the micro flow field at different axial positions of the liquid film at different speeds were investigated by numerical simulation under the two limit conditions of no slip(zero slip velocity)and no shear(maximum slip velocity)at the interface.The shear stress-velocity fitting model of the fluid groove interface was established.The results show that the tangential velocity of the liquid film is much larger than the radial and axial velocity,and the three-dimensional synthetic velocity distribution is mainly determined by the tangential velocity.The pres sure gradient of the flow field changes abruptly within 1μm of the step in the groove region,but the flow fields in the non-groove region and the groove region are relatively independent,and the former can be regarded as simple Couette flow and the latter is reverse pressure gradient Couette flow.The magnitude of the adhesive shear stress at the fluid-solid interface is closely related to the boundary velocity slip of the liquid film,and when the interfacial shear stress in the groove region becomes smaller,the boundary slip velocity and the velocity in all directions of the flow field inside and outside the groove become larger,and the higher the speed,the greater the value.When it is not higher than 10000 r/min,the cavitation effect has little impact on the overall average velocity field,but when the velocity is higher,it is necessary to quantify the cavitation effect and modify the shear stress-velocity fitting model.

关 键 词：液膜密封 界面剪切 速度滑移 空化 微流场 

分 类 号：TH117[机械工程—机械设计及理论]