基于格子Boltzmann方法的动压气体轴承黏性热耗散研究

箔片气体轴承微间隙内的流场常处于滑移区，甚至过渡区，会出现一些微观效应，其热特性的研究采用宏观方法已不再合适。为研究不同工况下动压气体轴承间隙热特性变化规律，基于格子Boltzmann方法建立包含黏性热耗散项的径向轴承间隙传热数值模型；采用总能形式的双分布函数热模型，通过有限差分离散将其应用到贴体网格中，同时引入速度滑移和温度阶跃边界条件，通过数值计算得到不同参数下的轴承间隙气膜温度分布，并分析了不同埃克特数（Ec）、偏心率和转速条件以及温度阶跃对黏性热耗散的影响。结果表明，当Ec数、偏心率和转速增大时，气膜最高温度增加，两侧的温度阶跃增加；温度阶跃效应的忽略均会导致黏性热耗散量不同程度的低估。

Research on Viscous Heat Dissipation of Gas-Lubricated Journal Bearings Using the Lattice Boltzmann Method

The flow field in the micro-gap of foil gas bearing is often in the slip zone,even in the transition zone,and there will be some micro-effects,so it is no longer appropriate to use the macro method to study its thermal characteristics.To study the variation law of thermal characteristics in the clearance of gas-lubricated journal bearings under different working conditions,a numerical model of radial bearing clearance heat transfer including viscous heat dissipation was established based on the lattice Boltzmann method.The double distribution function thermal model in the form of total energy was adopted and applied to the body-fitted mesh through finite difference discretization,and the velocity slip and temperature jump boundary conditions were introduced to calculation the gas film temperature distribution in bearing clearance under different parameters by numerical simulation.The effects of different Eckert( Ec ) numbers,eccentricity ratios,rotational speed conditions,and temperature jump on viscous heat dissipation were analyzed.The results show that when the Ec number,eccentricity ratio,and rotational speed increase,the maximum temperature of the gas film increases,and the temperature jump on both sides increases.The neglect of the temperature jump effect will lead to different degrees of underestimation of the viscous heat dissipation.