基于流体压润滑理论的农用潜水泵机械密封性能的研究

Study on Sealing Performance of Submersible Pumps with Hydrodynamic Mechanical Seal

[目的]探讨动压槽的槽深、槽数对农用潜水泵机械泄漏量、液膜刚度等密封性能的影响。[方法]在潜水泵机械密封的设计上应用流体动压润滑理论,通过密封端面的斜直线槽产生流体动压效应,以提高密封装置的寿命。应用CFD技术建立密封的几何模型并进行数值模拟,以确保密封具有较小的泄漏量和较大的液膜刚度为优化准则,探讨动压槽的槽深、槽数等结构参数对泄漏量、液膜刚度等最佳密封性能参数的影响。[结果]外装式内侧斜直线槽密封具有明显的流体动压效应,能产生较大刚度的液膜,可实现密封端面非接触,减少摩擦磨损,能抵抗较为剧烈的外界工况变化;内侧斜直线槽能产生上游泵送效应,密封泄漏量小,当槽数为30,槽深为5～8μm时,密封综合性能最佳。[结论]斜直线槽密封具有泄漏量小、液膜刚度大等优点。

[ Objective ] The study aimed to discuss the influence of the depth and number of hydrodynamic groove on the sealing performance such as the leakage and liquid film stiffness of agricultural submersible pump. [ Method ] The hydrodynamic lubrication theory was applied on the design for the mechanical seal of the submersible pump and the hydrodynamic pressure effect could be produced through the skew line groove of the sealing surface to increase the life of the sealing device. The CFD technology was applied to establish the geometrical model and simulate the sealing performance so as to ensure the sealing process with a smaller seal leakage and larger liquid film stiffness as the optimal criteria and discuss the best sealing performance parameters of the depth and number of hydrodynamic groove to the leakage and liquid film stiffness etc. [ Result ] The externally mounted seal with inside skew line groove showed the obvious fluid dynamatic pressure effect and could generate the liquid film with the larger stiffness, which could set the seal surfaces apart, reduce the friction wear and could resist the more violent external condition change. The inside skew line groove could produce the upstream pumping effect and had samll seal leakage quantity, and when the groove number was 30 and the groove depth was 5 -8 μm, the seal comprehensive effect was best. [ Conclusion] The seal with the skew line groove had the advantages of small seal leakage quantity and great liquid film stiffness, etc.