孔隙深度对多孔储液介质摩擦学性能的影响研究

多孔储液介质凭借其独特的孔隙结构可以储存并释放润滑介质，具备良好的自润滑性能. 利用计算流体力学(CFD)方法研究了孔隙深度对多孔储液介质摩擦界面流体压力分布的影响；考虑气-液界面的弯月面力作用，研究了不同孔隙深度的多孔储液介质气-液承载模型以及气-液二相的最小压差分布规律. 基于模拟计算结果，采用3D打印技术制备了不同孔隙深度的多孔储液介质，进一步考察了孔隙深度对其摩擦学性能的影响. CFD模拟结果表明合理设计孔隙深度能够增强多孔储液介质的流体动压润滑效应，孔隙深度较低会使得润滑升力不足，孔隙深度过高又会使得孔隙中流体产生回流循环，削弱楔形效应. 气体进入多孔储液介质摩擦副表面后，在孔隙中形成气-液二相受压承载，其最大承载力随着孔隙深度的增加先升高后趋于平稳，但孔隙深度越小，对润滑作用的积极效果越显著. 摩擦试验表明多孔储液介质的摩擦系数随着孔隙深度的增加呈先降低后增加的趋势，与模拟计算结果一致. 因此合理设计多孔储液介质的孔隙深度，能优化多孔储液介质的润滑性能.Porous liquid-storing media can store and release lubricating media with their unique pore structures, and possess excellent self-lubricating performance. The effects of pore depth on the fluid pressure distribution at the frictional interface of porous liquid-storing media were investigated using Computational Fluid Dynamics (CFD) methods. Considering the meniscus force at the gas-liquid interface, the gas-liquid load-bearing models of porous liquid-storing media with different pore depths and the distribution law of the minimum pressure difference of gas-liquid two-phase flow were studied. Based on the simulation results, porous liquid-storing media with different pore depths were fabricated via 3D printing technology, and the effect of pore depth on their tribological performance was further examined. CFD simulation results indicate that properly designing the pore depth can enhance the hydrodynamic lubrication effect of porous liquid-storing media: insufficient lubricating lift will be caused when the pore depth is too small, while an excessively large pore depth will lead to backflow circulation of fluid inside the pores, weakening the wedge effect. After gas enters the frictional interface of the porous liquid-storing media tribopair, compressed load-bearing of gas-liquid two-phase flow is formed within the pores. The maximum load-bearing capacity first increases with the increase of pore depth and then tends to stabilize, while smaller pore depths bring more pronounced positive effects on lubrication. Friction tests show that the friction coefficient of porous liquid-storing media first decreases and then increases with the increase of pore depth, which is consistent with the simulation results. Therefore, rationally designing the pore depth of porous liquid-storing media can optimize their lubricating performance.