螺旋槽端面密封的刚度特性

Stiffness characteristics of spiral grooved face seals

为了解决螺旋槽端面密封在不同环境下的刚度设计问题,对其刚度特性进行了数值计算和影响因素分析.采用Possion方程定解的贴体坐标生成计算网格,将螺旋槽不规则曲线边界转换为规则矩形边界.将Reynolds方程转换到计算平面,采用基于贴体坐标系的有限差分方法对Reynolds方程进行数值求解,得到螺旋槽密封刚度特性数值模型,并分析了内外径比和转速对密封刚度特性的影响.结果表明:当其他参数固定,内外径比为0.5～0.6时,流体膜具有最大的刚度;随着密封外径的增大,刚度整体有所提高,内外径比对刚度的影响更为显著;流体膜刚度随转速的升高而线性增大,并且内外径比为0.5～0.6时,刚度增大幅度最大;对于窄面密封,当扰动随转速成比例提高而导致密封刚度不足时,必须提高内外径比才能保证密封的正常工作.

To solve the stiffness design problems of spiral grooved face seals in different working conditions,the stiffness coefficient was numerically calculated,and the influencing factors of stiffness were analyzed.The Possion′s equation was used to generate boundary-fitted coordinate（BFC） grid system,and spiral curvilinear grid system was obtained with a coincident boundary of irregular physical area.Applying finite difference method（FDM） based on BFC,the Reynolds equation was discretized and numerically calculated in the computational plane.The effects of rotational speed and the ratio of inner radius over the outer radius on stiffness were analyzed.It was found that the lubricant film obtained the biggest stiffness coefficient when the radius ratio was 0.5～0.6 on the condition that the test parameters were fixed.With outer radius increasing,the stiffness increased and the effect of radius ratio was more significant.The stiffness coefficient increased linearly with increasing rotational speed,and a maximum coefficient was observed when the radius ratio was 0.5～0.6.For the narrow face seals,when stiffness coefficient was deficient which is caused from an increased perturbation that is proportional to the rotational speed,a larger radius ratio will be necessary to ensure the seals work properly.