厚顶箔的箔片动压轴承性能的数值研究

提出了一种具有厚顶箔特征的箔片动压轴承(TTF-GJFB),并对其进行了建模及分析。针对这种型轴承,采用Newton-Raphson迭代法求解静态气膜雷诺润滑方程和箔片受力方程;采用折合系数法和小扰动法,推导了厚顶箔轴承的动态刚度系数与动态阻尼系数。以此为基础,对厚顶箔轴承和传统箔片轴承进行了对比,并对初始轴承间隙、波箔宽度、顶箔质量对厚顶箔轴承动静态特性的影响进行了研究。结果表明:厚顶箔轴承比传统箔片轴承拥有较大的承载力及偏位角,承载力增幅至少为23%;厚顶箔轴承的动态特性与传统箔片轴承有较大差异;厚顶箔轴承的初始间隙会影响偏位角和承载力,小初始间隙在所有偏心率范围内可以提高承载力和减小偏位角;波箔宽度对轴承静态特性的影响较小,但对动态特性的影响较大,在中低激振比范围内,动态系数基本随着箔片宽度的变窄而变小;厚顶箔的质量会在高激振比下对轴承的动态特性产生影响,使得动态刚度系数上升,动态阻尼系数下降。

Numerical investigation of gas journal foil bearing performance with thick top foil

A type of gas journal foil bearing with thick top foil (TTF-GJFB) was presented, and its modeling and analysis were carried out. The Newton-Raphson iterative method was used to solve the Reynolds equation and the force equilibrium equation to predict this novel bearing static performance. The dynamic stiffness and damping coefficients of this bearing were derived and solved by using reduced coefficient method and small perturbation method. Based on those methods, the comparative study of TTF-GJFB and traditional foil bearing was carried out, and the effects of bearing initial clearance, bump foil width and top foil mass on the bearing performance of novel foil bearing were studied. Results showed that TTF-GJFB had higher bearing load capacity and deflection angle than traditional foil bearing. The capacity increase was at least 23%. The dynamic characteristics of TTF-GJFB differed from those of traditional foil bearing. The initial clearance of TTF-GJFB affected the attitude angle and bearing load capacity. The width of the bump foil had great effect on the dynamic characteristics. Within the range of medium and low excitation ratio, the dynamic coefficients decreased with the declining width of the bump foil. The mass of top foil of TTF-GJFB affected the dynamic characteristics of bearing at high excitation ratio, dynamic stiffness coefficient increased and dynamic damping coefficient decreased.