考虑对流换热系数的非对称斜齿轮喷油润滑分析研究

Analysis and Research of Asymmetric Helical Gear Oil Injection Lubrication Considering Convective Heat Transfer Coefficient

针对非对称斜齿轮喷油润滑啮入侧喷油和啮出侧喷油两种喷油方式,运用计算流体动力学方法进行了研究。基于有限元方法得到了喷油润滑仿真模型的热边界条件;在CFX流体仿真软件中对非对称斜齿轮喷油润滑进行仿真计算,得到了喷油参数在不同喷油方法下对齿面对流换热系数的影响规律。啮入侧喷油润滑方法下,润滑油黏度增大,齿面平均对流换热系数将随着减小,但减小的趋势变缓;啮出侧喷油润滑方法下,随着润滑油黏度的增大,齿面平均对流换热系数逐渐减小,但减小的程度越来越缓慢,说明齿面平均对流换热系数受到润滑油黏度的影响越来越小。啮入侧喷油方法和啮出侧喷油方法下的齿面对流换热系数均随着喷油速度的增大而增大,线性变化明显。说明喷油速度对齿面平均对流换热系数的影响较明显。啮入侧喷油润滑方法和啮出侧喷油润滑方法在相同润滑油黏度和相同喷油速度条件下,啮入侧喷油方法时的齿面对流换热系数较大。

The computational fluid dynamic(CFD)method is used to study the two injection modes of the non-symmetrical helical gear injection,namely,the injection mode of the entry side and the injection mode of the exit side.The thermal boundary conditions of the injection lubrication simulation model are obtained based on the finite element method.The simulation calculation of the injection lubrication of the asymmetric helical gear is carried out in the CFX fluid simulation software,and the influence rules of the injection parameters on the flow heat transfer coefficient of the tooth face under different injection methods are obtained.Under the meth⁃od of oil injection lubrication on the meshing entry side,the average convective heat transfer coefficient of tooth surface decreases with the increase of lubricating oil viscosity,but the decreasing trend is slow.Under the meth⁃od of oil injection lubrication on the meshing exit side,the average convective heat transfer coefficient of the tooth surface will gradually decrease as the viscosity of the lubricating oil increases,but the decreasing degree gets slower gradually.It shows that the average convective heat transfer coefficient of the tooth surface is less and less affected by the viscosity of the lubricating oil.The tooth-to-surface flow heat transfer coefficients of the two oil injection methods,the meshing entry side oil injection method and the meshing exit side oil injection method,both increase with the increase of the fuel injection speed,and the linear change is obvious.The effect of oil injection velocity on the average convective heat transfer coefficient of tooth surface is obvious.Under the conditions of the same lubricating oil viscosity and the same oil injection speed,the meshing entry side oil injec⁃tion lubrication method and the meshing exit side oil injection lubrication method have a larger tooth flow heat transfer coefficient during the meshing entry side oil injection method.