计入应力偶效应的滑动轴承热流体混合润滑研究

Mixed Thermo-hydrodynamic Analysis of Journal Bearings with Couple Stress Lubricants

考虑含添加剂润滑油的应力偶效应,以倾斜轴承为研究对象,建立动载荷轴承热流体混合润滑模型,探讨倾斜角、表面粗糙度及应力偶效应等参数的耦合作用对轴承润滑性能以及润滑状态的影响规律。结果表明,应力偶效应减弱了热流体润滑轴承最大油膜压力增加的现象,且随着应力偶效应的增强,最大油膜压力的减小幅度逐渐增大;与牛顿流体相对,应力偶流体润滑下轴承的油膜温度降低,高温区域的油膜面积减小,轴颈附近油膜温度下降;增大轴颈倾斜角,流体内部的最大油膜温度增加;当应力偶参数较大时,倾斜角对油膜最大温度以及节点应力偶参数值的影响逐渐减弱;当应力偶参数较小时,增大表面粗糙度,混合润滑与流体动力润滑状态转变的临界转速增加,对应的最小摩擦因数增大。

Considering couple stress effect of lubricant additives,the misaligned bearing is used as the research object,and the mixed thermo-hydrodynamic lubrication model of dynamically loaded bearing is established to explore the coupling effects of misalignment angle,surface roughness and couple stress effect on the lubrication performance and lubrication state.The results show that couple stress effect weakens the phenomenon of increasing the maximum oil film pressure of bearing lubricated with thermal fluid,and the decrease of the maximum oil film pressure gradually increases with the increase of the couple stress effect;compared with the Newtonian fluid,oil film temperature of the bearing with couple stress lubricants decreases,the oil film area in the high temperature area decreases,and the oil film temperature near the journal decreases;increasing the misalignment angle,the maximum oil film temperature inside the fluid increases;with the enhancement of the couple stress effect,the influence of the misalignment angle on the maximum oil film temperature and the value of the nodal couple stress parameter gradually decreases;when the couple stress parameter is small,increasing the surface roughness,the critical speed of the transition between mixed lubrication and hydrodynamic lubrication state increases,and the corresponding minimum friction coefficient increases,and the corresponding minimum friction coefficient increases with the increase of surface roughness.