转静子接触面超声减摩机制及应用研究

The small turbine type rotating machineries are often damaged and the rotor system may lose stability due to rotor-to-stator rub. Aiming at this problem, this project presents to apply the ultrasonic friction-reduction mechanism to rotor system, in order that the rotor-to-stator rub can be eliminated or the friction force be reduced, and the operating stability of the rotor system of this type of rotating machinery be improved. This project will study the levitation mechanism of the squeeze film with complex boundary by applying the athletic differential equation theory, and study the friction-reduction mechanism of the hybrid friction condition by combining tribology theory and contact theory together. It will also study the stability of the ultrasonic imposed rotor system based on the nonlinear dynamics theory, and the ultrasonic parameters matching method by adopting optimization theory. It's expected that the mechanism of levitation and friction-reduction by ultrasonic in the rubbing rotor system will be mastered, and also the responses and time-varying stability principles of the rubbing rotor system with ultrasonic imposing. It's also expected that the influences of parameters on ultrasonic friction-reduction will be mastered, and the ultrasonic parameters matching method to improve the stability of the ultrasonic imposed in rotor system will also be obtained. The project can build the theory basis for the acturally application of the ultrasonic friction-reduction mechanism to the rub reduction of the small scale rotating machinery, and it also means much to the control or restrain of other common faults in rotating machinery.

针对目前涡轮类小型旋转机械转子系统经常发生转静子摩擦，从而造成破坏并影响系统稳定运行的问题，提出将超声减摩机制应用于转子系统的摩擦抑制，即通过超声作用消除摩擦或减少转静子之间的摩擦力，提高该类旋转机械转子系统的运行稳定性。 项目将采用流体运动微分方程理论研究复杂边界挤压膜悬浮机理、结合摩擦和接触理论研究超声激励下混合摩擦面减摩机理、基于非线性动力学理论研究超声作用下转子系统的振动特性和运行稳定性、运用优化方法研究超声减摩转子系统的参数优化匹配。 项目预期将阐明摩擦转子系统中超声悬浮和超声振动减摩的作用机制，掌握超声减摩转子系统的非线性振动特性和时变运行稳定性规律，探明各种参数对超声减摩作用的影响规律，获得实现超声减摩转子系统稳定运行的参数匹配方法。 项目的研究可以为超声减摩在小型旋转机械摩擦抑制中的实际应用奠定理论基础，对旋转机械其他常见故障的控制和抑制也具有重要意义。

针对目前涡轮类小型旋转机械转子系统经常发生转静子摩擦，从而造成破坏并影响系统稳定运行的问题，提出将超声减摩机制应用于转子系统的摩擦抑制，提高该类旋转机械转子系统的运行稳定性。.项目研究了复杂边界挤压膜悬浮机理、混合摩擦面减摩机理，还研究超声作用下转子系统的振动特性和运行稳定性、研究超声减摩转子系统的参数优化匹配问题。主要结果如下：.(1)超声悬浮力可以用来抑制转子系统不平衡振动；正常气压下，超声悬浮力在牛顿级；随着气压增大，悬浮力还能增大。悬浮间隙、超声振幅、超声频率、径向纹理表面粗糙度等对超声悬浮力影响大。.(2)混合摩擦超声轴承的承载能力远大于悬浮时的承载能力，且平均摩擦因数要比材料摩擦因数小很多；摩擦因数随着超声振动频率升高、超声波振幅增大而降低，但转速对摩擦因数变化的影响较小。平均摩擦因数可以小于材料摩擦因数的50%。.(3)超声减摩可以应用于摩擦故障转子系统的振动抑制中，通过改变转子系统的时域响应、热传递量，进而改变系统的稳定区域。对于轻微的摩擦故障，可以消除其热弯曲；对于严重的摩擦转子系统，或者载荷较大的转子系统，超声作用只能在一定程度上防止和减少摩擦热弯曲。.(4)根据研究结果，提出了超声悬浮轴承和超声减摩轴承的参数优化匹配方法和步骤。超声悬浮轴承由三超声振子组成，可以用来替代润滑油或润滑脂，实现超声润滑；超声减摩轴承为全包容式径向超声挤压轴承，可以用来控制转子振动，提高其稳定性。.综上，经过4年的研究，已经建立了转子系统摩擦抑制的超声减摩理论体系。项目的研究为超声减摩在小型旋转机械摩擦抑制中的实际应用奠定理论基础，也对旋转机械其他常见故障的控制和抑制具有参考意义。