假塑性流体润滑有限宽向心轴承的热流体动力分析

The Thermohydrodynamic Analysis of Finite Journal Bearings Lubricated with Pseudo-Plastic Lubricants

本文采用的流变模型和简化的热传导边界条件,用有限元法联立求解雷诺方程和能量方程,得到了假塑性流体润滑向心轴承性能的热流体动力分析的数值解。在计算过程中,采用了不完整的上游边界及沿膜厚方向的平均粘度概念。结果表明,采用不完整的上游边界能较好地描述轴承的实际工况,并使在热流体动力分析中用计算确定混合系数η_(mix)值成为可能。研究还表明,考虑热效应时,假塑性流体的粘度指数改善特性对由于剪切减薄特性引起的承载能力下降有着很大的补偿作用。实验结果和理论分析的一致性较好。

Using the rheological model,η=η0γn-1e-βΔT,and the simplified boundary conditions of heat conduct ion,the Reynolds equation and the energy equation were solved simultaneously with Finite Element Method ( FEM ) ,and the numerical solution of the thermohydrodynamic( THD ) performances of journal bearings lubricated with pseudo-plastic lubricants were obtained. During calculation, the concepts of a new upper boundary condition(UBC)of oil flow and the average viscosity across the oil film thickness were used.The resultss howed that the incomplete UBC described the practical operating conditions quite well and made it possible to determine numerically the mixed coefficient ηmix, which was used in THD analysis.The results also showed that the property of improving the Viscosity Index had a great complementary effect on the loss of load capacity produced by shear thinning for the pseudo-plastic lubricants.The agreement between the theoretical and experimental results is quite well.