摘要
为研究等温条件下幂函数非牛顿流体的弹流润滑特性,基于Ostwald本构模型,采用普适流体润滑方程来求解非牛顿流体润滑问题,探讨了等温、稳态条件下流变指数、载荷、卷吸速度等参数对点接触弹流润滑特性的影响,并与相同工况下牛顿流体弹流润滑的结果进行了比较.再以某一特定流变指数的流体进行弹流润滑实验测量其膜厚,分析卷吸速度和载荷对膜厚的影响.结果表明:润滑剂的非牛顿性越显著,润滑膜厚会越小,压力分布会越接近Hertz接触应力分布,载荷和卷吸速度对非牛顿流体的润滑膜厚及压力分布的影响比对牛顿流体的影响要小.同工况下,非牛顿流体的膜厚均小于牛顿流体的膜厚.从实验测量结果与数值计算结果对比分析可以得出,卷吸速度和载荷对膜厚的影响趋势基本吻合.
In order to study the elastohydrodynamic lubrication characteristics of power function non-Newtonian fluids under isothermal conditions,based on the Ostwald constitutive model,the non-Newtonian fluid lubrication problem was solved with the universal fluid lubrication equation. The effects of parameters such as rheological index,load,and entrainment velocity on the point contact EHL under isothermal and steady state conditions were discussed. A comparison between the non-Newtonian fluid and the Newtonian fluid was made. Then,the film thickness was measured by elastohydrodynamic lubrication experiment with a certain rheological index,and the effect of the entrainment velocity and the load on the film thickness was analyzed. The results show that when the non-Newtonian properties of the lubricant are more significant,the lubricant film will become less thick,and the pressure distribution will be closer to the Hertz contact stress distribution,and the influence of the load and the entrainment velocity on the lubricant film thickness pressure distribution of non-Newtonian fluids will be smaller than that on the Newtonian fluids. Under the same conditions,the film thickness of non-Newtonian fluid is smaller than that of the Newtonian fluid. From the comparison of the experimental measurement results with the numerical calculation results,it can be concluded that the effect of the entrainment velocity and load on the film thickness is basically consistent.
引文
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