Rotor-to-Stator Friction Simulation with Nonconstant Stiffness of the Contact Surfaces and Small Clearance between Them

IF 0.5 4区 工程技术 Q4 ENGINEERING, MECHANICAL
A. N. Nikiforov
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Abstract

Analytical and numerical modeling approaches for the contact-working system of turbo- and electric machines have been developed. The simulation allows determining some dynamic characteristics and loads in the rotor–stator system when there is a loss in clearance between them and there occurs subsequent motions with impacts or without separation from each other. In the system, the rotor and stator are deformable, the stiffness of rubbing surfaces is variable, and the working clearance between them is extremely small (50–500 times less than the rotor radius at the contact point). It is shown that the effect of the absolute elasticity for stator generates a significant change in natural oscillations of the coupled rotor–stator system, that is, a significant change in its eigenfrequencies and eigenmodes. It is noted that the elastic deformation of rubbing surfaces leads to a nonlinear increase in their contact stiffness, which consists of quasi-static and dynamic components. The consequences of an extremely small clearance are an elastic deformation of the contact surfaces commensurate with it (up to half the clearance size at the point of contact) during whirling with slipping of rotor over stator, as well as the disappearance of pure rolling, which is accompanied by the actual absence of rotary speeds even at low frequencies of contact whirling. The resulting diagrams of changes in the contact stiffness and whirling frequencies and the XY trajectories can serve as sources of initial information for identifying the operation of a real rotary machine on the threshold of a dangerous whirling with slipping and whipping and for further studies of contact oscillations of rotors.

Abstract Image

具有接触面非恒定刚度和小间隙的转子-定子摩擦仿真
已经开发了涡轮和电机接触工作系统的分析和数值建模方法。模拟允许确定转子-定子系统中的一些动态特性和负载,当它们之间存在间隙损失,并且随后发生有冲击或没有相互分离的运动时。在该系统中,转子和定子是可变形的,摩擦表面的刚度是可变的,并且它们之间的工作间隙非常小(比接触点处的转子半径小50–500倍)。研究表明,定子的绝对弹性效应会使转子-定子耦合系统的固有振荡发生显著变化,即其本征频率和本征模发生显著变化。值得注意的是,摩擦表面的弹性变形导致其接触刚度的非线性增加,接触刚度由准静态和动态分量组成。极小间隙的后果是,在转子在定子上滑动的旋转过程中,与之相当的接触表面发生弹性变形(高达接触点处间隙大小的一半),以及纯滚动的消失,即使在接触旋转的低频率下,也会伴随着实际的转速缺失。由此产生的接触刚度和旋转频率以及XY轨迹的变化图可以作为初始信息源,用于识别真实旋转机器在具有打滑和抖动的危险旋转阈值上的操作,以及用于进一步研究转子的接触振荡。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Journal of Friction and Wear
Journal of Friction and Wear ENGINEERING, MECHANICAL-MATERIALS SCIENCE, MULTIDISCIPLINARY
CiteScore
1.50
自引率
28.60%
发文量
21
审稿时长
6-12 weeks
期刊介绍: Journal of Friction and Wear is intended to bring together researchers and practitioners working in tribology. It provides novel information on science, practice, and technology of lubrication, wear prevention, and friction control. Papers cover tribological problems of physics, chemistry, materials science, and mechanical engineering, discussing issues from a fundamental or technological point of view.
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