密封面磨损对V形组合密封圈性能的影响_张毅.pdf

第 30 卷第 2 期2023 年 4 月 工程设计学报 Chinese Journal of Engineering DesignVol.30 No.2Apr.2023密封面磨损对V形组合密封圈性能的影响张毅，熊思阳，钟思鹏，熊子杰，杨强（西南石油大学 机电工程学院，四川 成都 610500）摘 要：密封面磨损对V形组合密封圈的密封性能有显著影响。建立了V形组合密封圈的有限元模型，基于V形圈接触压力大的地方磨损较快且磨损较大的区域向空气侧移动的特点，在有限元仿真计算中通过修改V形圈的轮廓来表示V形组合密封圈不同的磨损状态，进而研究密封圈在不同磨损状态下的接触压力分布情况。考虑到V形组合密封圈变形与润滑油膜之间的耦合作用，基于弹性流体动压润滑理论，建立了V形组合密封圈弹流润滑数学模型。基于小变形理论，通过变形影响系数矩阵法得到V形组合密封圈在高压作用下的弹性变形，通过有限差分法求解了密封圈在工作过程中的油膜压力分布和厚度分布，分析了密封面磨损和粗糙度对组合密封圈润滑性能的影响。搭建了V形组合密封圈性能实验台，得到了在轻度和中度磨损状态下密封圈在不同电机转速下的摩擦扭矩和泄漏率，并将实验结果与仿真结果进行对比。结果表明：随着磨损加剧，靠近润滑油一侧油膜的压力和厚度增大；对于已经发生磨损的密封圈，粗糙度的提高会使其油膜压力增大；转速提高会使密封圈所受的摩擦扭矩和泄漏率增大。研究结果为提高V形组合密封圈的性能提供了参考。关键词：弹流润滑模型；磨损；粗糙度；旋转密封圈中图分类号：TQ 336.42 文献标志码：A 文章编号：1006-754X（2023）02-0237-07Effect of sealing surface wear on the performance of V-shaped combined sealing ringZHANG Yi,XIONG Siyang,ZHONG Sipeng,XIONG Zijie,YANG Qiang(School of Mechatronic Engineering,Southwest Petroleum University,Chengdu 610500,China)Abstract：The wear of the sealing surface has a significant impact on the sealing performance of V-shaped combined sealing ring.A finite element model of the V-shaped combined sealing ring was established.Based on the characteristics of rapid wear in areas with high contact pressure and the movement of the area with greater wear towards the air side,the contact pressure distribution of the sealing ring under different wear states was studied by modifying the contour of the V-shaped ring in the finite element simulation process to represent the different wear states of the V-shaped combined seal.Considering the coupling effect between deformation of V-shaped combined sealing ring and lubricating oil film,based on the elastohydrodynamic lubrication theory,an elastohydrodynamic lubrication mathematical model for V-shaped combined sealing ring was established.Based on the small deformation theory,the elastic deformation of the sealing ring under high pressure was obtained by the deformation influence coefficient matrix method.The oil film pressure distribution and thickness distribution in the working process of the sealing ring were solved by the finite difference method,and the influence of the wear and roughness of the sealing surface on the lubrication performance of the combined sealing ring was analyzed.A V-shaped combined sealing ring performance test bench was built to obtain the friction torque and leakage rate of the sealing ring under mild and moderate wear conditions at different motor speeds,and the test results were compared with the simulation results.The doi:10.3785/j.issn.1006-754X.2023.00.017收稿日期：20220427 修订日期：20220524本刊网址在线期刊：http:/ 毅(1983)，男，河南南阳人，讲师，博士，从事智能钻采工具和极端工况下动态密封润滑研究，E-mail:,http:/orcid.org/0000-0002-1650-3898工程设计学报第 30 卷 results showed that as wear intensified,the pressure and thickness of the oil film near the lubricating oil side increased;for seals that had already undergone wear,an increase in roughness would increase the oil film pressure;an increase in motor speed would increase the frictional torque and leakage rate of the sealing ring.The research results provide a reference for improving the performance of V-shaped combined sealing ring.Key words：elastohydrodynamic lubrication model;wear;roughness;rotary seal ringV形组合密封圈应用于许多工业领域，如常用于航空执行器、高压油缸和钻井工具等的高压密封1。密封圈磨损对密封结构的性能有着重要影响2，很多学者对密封圈进行了研究。如：欧阳小平等3基于混合润滑模型，分析了V形组合密封圈的工作参数对其密封性能的影响；Hai等4对V形组合密封圈的径向载荷进行了模拟，指出精确划分动密封磨损区域的网格可以提高计算精度；Sui等5通过数值模拟得到了旋转密封圈的接触压力分布，并通过实验验证了模拟结果。为了进一步研究密封圈磨损对其润滑性能的影响，Burkhart等6-9基于实验结果编制了程序，对动密封的磨损进行了研究。在动密封弹流润滑模型方面，杨化林等10-11通过建立润滑数学模型，计算了密封圈工作时润滑油的泄漏率；Nikas等12通过实验对密封圈的润滑模型进行了修正。此外，有学者研究了密封圈粗糙度对其润滑性能的影响。如：Salant等13建立了考虑粗糙度的往复密封润滑模型，分析了粗糙度对油膜状态及密封圈磨损的影响；Hajjam等14通过对唇形密封圈的性能分析，证实了粗糙度对动密封的润滑特性有很大影响。目前，学者们主要研究了粗糙度对密封圈润滑状态的影响及在实际使用中旋转密封圈的磨损过程，而没有分析密封面磨损对V形组合密封圈润滑状态的影响。在实际工况下，密封面的磨损对密封圈润滑状态有明显的影响。因此，本文根据V形组合密封圈接触应力的分布来判断密封面磨损情况，并拟合磨损后密封面的轮廓曲线，再通过数值模拟来研究密封面磨损影响下V形组合密封圈的性能，最后通过实验来验证仿真结果的正确性。1 V形组合密封圈润滑模型 V形组合密封圈的结构如图1所示。1.1密封圈润滑油膜的形成机理根据弹性流体动压润滑理论，当轴旋转时，由于弹流动压效应，密封区域会形成高压润滑油膜，如图2所示。图中x、y、z向分别为密封圈与轴实际接触区域周向、轴向及油膜厚度方向。润滑油膜可以减小密封区域接触面的摩擦力15。1.2流体润滑方程为了便于润滑数学模型的建立与求解，根据V形组合密封圈的实际工况，作出如下假设：1）不考虑接触面法向速度对油膜压力的影响；2）密封区域完全是弹性体；3）润滑油是不可压缩的。在上述假设下，忽略密封区域的膨胀效应和挤压效应，则V形组合密封圈的雷诺方程可以简化为：x(h3px)+y(h3py)=6vxhx(1)式中：h为密封间隙中油膜厚度，m；p为密封间隙中润滑油的压力，Pa；为润滑油黏度，Pas；vx为润滑油周向的速度，m/s。雷诺边界条件和质量守恒边界条件通常用于弹流润滑模型的研究16。根据V形组合密封圈的工况，定义雷诺边界条件为:|p()x,yin=psp()x,yout=pap()x,y|x=0=p()x,y|x=lp()x,y 0(2)图1V形组合密封圈的结构Fig.1Structure of V-shaped combined sealing ring图2V形组合密封圈润滑油膜示意Fig.2Schematic of lubricating oil film of V-shaped combined sealing ring 238第 2 期张毅，等：密封面磨损对V形组合密封圈性能的影响式中：yin,yout为y轴边界坐标值；pa为标准大气压，Pa；ps为密封压力，Pa；l为V形密封圈与轴实际接触区域周向的长度。对式(1)进行无量纲化处理，得到:X(H31PX)+2Y(H31PY)=VxHX(3)式中：X=x/l,0X1;Y=y/b,0Y1，b为V形密封圈与轴实际接触区域轴向的长度；P=p/p0，p0为油膜初始压力；H=h/h0，h0为油膜初始厚度；1=/0，0为标准大气压下的润滑油黏度；为接触区域长宽比，=l/b；Vx=6vxl0/(h20p0)。1.3油膜厚度计算根据弹流润滑理论，油膜厚度主要与密封区域的弹性变形和密封接触区域的表面粗糙度有关。油膜厚度为17：h=ushaft+useal-u0+Ra(4)式中：ushaft为轴表面变形量，由于旋转轴的刚度远大于V形圈的刚度，可设ushaft=0；useal为V形圈的变形量；u0为施加介质压力前V形圈的初始压缩变形量；Ra为密封圈的表面粗糙度。1.4密封圈所受摩擦力计算V 形组合密封圈周向的剪切应力x可以表示为17：x=vxz(5)密封圈所受摩擦力F为：F=x|z=h