混合式动压气体轴承结构优化与可靠性分析

通过将径向、止推螺旋槽动压气体轴承相结合，建立了混合式动压气体轴承的润滑分析模型。阐述了其结构特点与润滑机理，建立轴承无量纲稳态Reynolds控制方程。提出混合式动压气膜压力耦合计算方法，推导气膜压力差分表达式，定义边界条件，构建气膜压力分布的数值计算方法。以最大径向承载力为目标优化结构参数。基于最优结构参数建立轴承气膜有限元模型，运用CFD分析轴承转子系统受不同冲击载荷时径向稳定性变化规律，研究混合式动压气体轴承动态特性与可靠性。搭建混合式动压气体轴承试验台，验证数值计算方法和有限元仿真分析的正确性。结果表明:提出的压力耦合计算方法可以准确地计算分析稳态气膜压力分布、承载力和承载性能，有限元仿真能更好地模拟动态流场变化，计算分析动态承载力、动态特性系数和稳定性。高转速下混合式气体轴承承载力、稳定性较好，对单向阶跃力、单向矩形力的抗冲击能力强，可靠性强。混合式动压气体轴承在优化承载性能与刚度的同时，应考虑抗冲击特性和稳定性以提高轴承的综合性能。 

Structural optimization and reliability analysis of hybrid dynamic pressure gas bearings

By combining radial and thrust spiral groove dynamic pressure gas bearing，the lubrication analysis model of hybrid dynamic pressure gas bearing was established.The structure characteristics and lubrication mechanism of the mixed dynamic pressure gas bearing were expounded，and the dimensionless steady state Reynolds governing equation of the bearing was established.A hybrid dynamic pressure film pressure coupling calculation method was proposed，differential expression of gas film pressure was derived，boundary conditions were defined，and a numerical calculation method of gas film pressure distribution was constructed.The maximum radial bearing capacity was taken as the objective to optimize the structural parameters.Based on the optimal structural parameters，the finite element model of bearing gas film was established，and the radial stability variation law of bearing rotor system under different impact loads was analyzed using CFD，so as to study the dynamic characteristics and reliability of hybrid dynamic pressure gas bearing.The test bed of hybrid dynamic pressure gas bearing was built to verify the correctness of numerical calculation method and finite element simulation analysis.The results showed that the proposed pressure coupling calculation method can accurately calculate and analyze the steady-state gas film pressure distribution，gas film force and bearing capacity，and the finite element simulation can better simulate the dynamic flow field change，and also calculate and analyze the dynamic gas film force，dynamic characteristic coefficient and stability.The good bearing capacity and stability of the mixed gas bearing at high speed have strong impact resistance and reliability to unidirectional step force and unidirectional rectangular force.When the bearing performance and stiffness were optimized，the impact resistance and stability should be considered to improve the comprehensive performance of the hybrid gas bearing.