为研究弹流润滑的非牛顿效应,对稳态和时变条件下等温点接触牛顿流体与非牛顿流体的弹流特性差异进行分析。假设润滑剂为Ree—Eyring非牛顿流体。研究卷吸速度、滑滚比、最大赫兹接触压力以及特征剪应力对弹流润滑性能的影响,分析时变条件下非牛顿流体的弹流特性,并与牛顿流体进行比较。结果表明,等温、轻载工况下,速度的增加导致牛顿流体产生较为尖锐的第二压力峰,导致非牛顿流体的接触区入口膜厚增加。且滑滚比越大增加越明显;高速、大滑滚比条件下,载荷越轻非牛顿效应越明显;时变条件下,速度波动对牛顿流体和非牛顿流体都产生较大影响,非牛顿流体的第二压力峰在各个瞬时始终小于牛顿流体。因此,等温点接触弹流润滑条件下,动态效应和非牛顿效应不应忽视。
In order to investigate the non-Newtonian effect of elastohydrodynanuc lubrication (LI-IL), the EHL cnarac- teristics difference between Newtonian fluid and non-Newtonian fluid in steady state and time-varying condition was dis- cussed.The lubricant was assumed to be a Ree-Eyring non-Newtonian fluid, and the effects of entrainment velocity, slide- roll ratio, the maximum Hertzian pressure and the characteristics shearing stress on the EHL performances were studied.The time-dependent EHL performance of non-Newtonian fluid was analyzed, and was compared with that of Newtonian fluid. Re- suits show that, under isothermal and light load conditions, the increasing in the entrainment velocity leads to a sharp sec- ond pressure peak for Newtonian fluid, and the increasing of the entrance film thickness for non-Newtonian fluid, especially under the condition of large slide-roll ratio.Under the condition of high speed and large slide-roll ratio, the lighter the load, the more apparent the non-Newtonian effect. Under the time-varying condition, the entrainment velocity fluctuation has a great influence on both Newtonian and non-Newtonian fluid, the second pressure peak of the non-Newtonian fluid is always smaller than that of the Newtonian fluid at each instant.Therefore, dynamic effects and non-Newtonian effect should not be ignored for the study of isothermal point contact EHL.