航空发动机高速滚动轴承动力学行为研究

发布时间：2018-07-07 15:45

本文选题：航空发动机 + 高速滚动轴承　；参考：《哈尔滨工业大学》2013年博士论文

【摘要】：航空发动机不断向大推重比、长寿命和高可靠性方向发展，对航空发动机高速滚动轴承的转速、载荷等指标提出了越来越苛刻的要求。长期工作在高转速和重载荷情况下的滚动轴承常呈现应力过大、温升过高等特点，发生擦伤、烧伤等失效，严重的还会带来轴承卡死抱轴等严重后果。为此，对高速滚动轴承作了大量的结构及材料方面的改进和创新，然而快速提升的苛刻工况条件已经逼近了现有材料的使用极限。同时，航空发动机在工作过程中的高转速巡航以及多工况转换的特点，使得滚动轴承的动态稳定性问题日益凸显，带来保持架断裂、转子系统失稳等严重后果，在此背景下航空发动机高速滚动轴承的全工况包络设计显得不可或缺。因此，对航空发动机高速滚动轴承进行动态性能分析，研究其高速动力学行为，是面向工况进行轴承结构优化、保证轴承工作可靠性和延长轴承寿命的必不可少的共性基础研究课题。本文围绕航空发动机轴承典型苛刻工况条件，通过建模和仿真展开轴承动态性能研究，为轴承性能优化提供依据，为轴承—转子系统可靠性和稳定性增长研究奠定基础。论文通过轴承内部零件间的运动和位置关系分析，建立了零件间的相互作用模型，建立了高速球轴承和滚子轴承的完全动力学模型。采用Newtown-Raphson算法和Runge-Kutta算法结合的方法对动力学模型求解，解决了套圈和滚动体之间高频振动对计算效率的影响，同时保证了动力学结果的精度。分析结果为分析不同工况条件下轴承的动力学行为提供了基础数据。建立的动力学模型适用于油润滑和固体润滑轴承计算，可以分析轴承装配、温差及离心作用影响，可以分析球轴承保持架的椭圆兜孔形式以及滚子轴承的母线轮廓修型影响。针对轴承装配导致的内外圈轴线不对中现象，分析了轴承内外圈偏斜对承载区载荷特性的影响：轴承内外圈偏斜不仅导致承载滚动体发生偏载现象，引起局部接触应力过大，在轴承运转过程中还会因为变刚度振动而影响承载区最大接触应力的波动。随着内外圈偏转角度的增大，轴承接触区内最大接触应力值呈现逐渐上升趋于平稳的状态，，而承载区最大接触应力的波动幅度呈现先减小而后小幅增大的趋势。以改善内外圈偏斜对承载区最大接触应力的影响为目的，兼顾承载区应力波动幅度变化，给出了增加滚子数量及滚子母线对数修型的定量依据。根据建立的高速球轴承和滚子轴承动力学模型，从描述保持架稳定性的保持架质心涡动速度偏差比及反映滚动体整体打滑的保持架滑动率两方面分析了定常工况下高速滚动轴承的动态性能，分析结果可为轴承失效分析提供理论依据。结果表明：转速的增加可以提高保持架的稳定性，但导致滚动体打滑率上升。对于球轴承，控制径向载荷与轴向载荷的比值可以降低轴承滚动体的打滑率并有助于保持架稳定性的提升；对于滚子轴承，径向载荷的增加可以降低滚动体的打滑率，但同时导致保持架稳定性减弱。针对航空发动机工作中的多工况转换特点，分别就发动机启动、加速和加力三种过渡状态，分析了轴承的瞬态动力学行为。结果表明：保持架的稳定性与初始状态关系较大。轴承启动阶段，外引导保持架受滚动体推动，承受载荷较小，但在较长一段时间内处于不稳定状态；轴承加速和加载阶段，保持架受滚动体和引导套圈共同作用，速度或推力的增加会加剧保持架与套圈引导面及滚动体的碰磨。基于航空轴承高速、重载、高温的工况特点，建立了考虑配合、工作温度及高速离心载荷的轴承工作游隙计算模型，分析了轴承不同工况的工作游隙及其对轴承性能的影响。模型和分析结果为轴承配合参数设计提供指导。对建立的动力学计算模型，采用软件集成技术，通过Visual Basic和Matlab混合编程研制了滚动轴承动态性能分析软件。软件功能通过与SHABERTH软件及ADORE软件对典型算例的计算结果对比获得了模型和方法的准确性验证，表明本软件在轴承稳态动力学参数预测及轴承瞬态运动学预测两方面都具有较好的精度。基于考虑轴承微区接触载荷的疲劳寿命计算方法，建立了以疲劳寿命为目标函数，以保持架滑动率、内外圈沟曲率系数和填球角为约束条件的轴承结构参数优化模型。分析了轴承结构参数对轴承稳定性的影响。研究了轴承内外圈相对转动方式对轴承结构优化的影响。分析结果为航空发动机轴承的延寿方法提供了理论基础。针对高速轴承-转子系统的动力学耦合特点，建立了轴承-转子系统的耦合动力学分析模型，初步分析了转子对轴承动力学的影响：转子振动引起的滚动体和套圈间接触应力和相对滑动增大将对轴承疲劳寿命及温升产生不良影响，分析结果为进一步研究重载摩擦副接触微区的微观失效行为提供了基础。
[Abstract]:The aeroengine is constantly developing to the big push weight ratio, long life life and high reliability direction. It has put forward more and more demanding requirements for the speed and load of the aero engine high speed rolling bearing. The rolling bearings working in the condition of high speed and heavy load often present the high stress, high temperature rising, bruise, burn and so on. For this reason, a large number of structural and material improvements and innovations have been made for the high speed rolling bearings. However, the critical conditions for fast lifting have already approximated the limit of the use of the existing materials. At the same time, the high speed cruising and multi working conditions of the aero engine in the working process. The characteristic of conversion makes the dynamic stability of the rolling bearing become more and more prominent, which brings the serious consequences of the fracture of the cage and the instability of the rotor system. In this context, the full envelope design of the high speed rolling bearing of the aeroengine is indispensable. Therefore, the dynamic performance analysis of the high speed rolling bearing of the aero engine is carried out and the height of the aeroengine is studied. The fast dynamic behavior is an essential basic research subject for optimizing bearing structure, ensuring the reliability of bearing and prolonging the life of bearing. In this paper, the dynamic performance of bearing is studied by modeling and simulation, which provides the basis for the optimization of bearing performance. The research on reliability and stability growth of bearing rotor system lays the foundation.
Through the analysis of the motion and position relationship between the inner parts of the bearing, the interaction model between the parts is established and the complete dynamic model of the high speed ball bearing and roller bearing is established. The dynamic model is solved by combining the Newtown-Raphson algorithm with the Runge-Kutta algorithm, and the high frequency vibration between the ring and the rolling body is solved. The analysis results provide basic data for analyzing the dynamic behavior of bearing under different working conditions. The dynamic model is suitable for the calculation of oil lubrication and solid lubrication bearing, which can analyze the effect of bearing assembly, temperature difference and centrifugal effect, and can analyze the ball axis. The form of the elliptical pocket and the modification of the busbar contour of the roller bearing are adopted.
In view of the misalignment of the axis of the inner and outer ring caused by the bearing assembly, the effect of the deviation of the inner and outer ring of the bearing on the load characteristics of the bearing area is analyzed. The deviation of the inner and outer ring of the bearing not only causes the loading of the load-bearing roller, which causes the excessive local contact stress, but also affects the largest bearing area in the process of bearing operation because of the variable stiffness vibration. With the increase of the deflection angle of the inner and outer ring, the maximum contact stress in the bearing contact area tends to rise to a steady state, and the fluctuation amplitude of the maximum contact stress in the bearing area decreases first and then increases slightly, in order to improve the influence of the inner and outer ring deflection on the maximum contact stress in the bearing area. Taking account of the variation of the stress fluctuation range in the bearing area, the quantitative basis for increasing the number of rollers and the logarithmic modification of roller busbars is given.
Based on the dynamic model of the high speed ball bearing and roller bearing, the dynamic performance of the high speed rolling bearing is analyzed from two aspects, which describe the deviation ratio of the centering whirl velocity of the cage and the slip rate reflecting the overall skidding of the roller. The analysis results can provide the theoretical basis for the bearing failure analysis. The results show that the increase of the speed can increase the stability of the cage, but the roller skid rate increases. For the ball bearing, the ratio of the radial load to the axial load can reduce the slipping rate of the bearing roller and help to improve the stability of the cage; for the roller bearing, the increase of the radial load can reduce the rolling body. The slipping rate, at the same time, causes the cage stability to weaken.
The transient dynamic behavior of the bearing is analyzed in three transition states, which are engine starting, accelerating and adding force respectively. The results show that the stability of the cage is closely related to the initial state. The external guide cage is driven by the rolling body in the starting stage of the bearing, but the load is less, but the load is less. In a longer period of time, it is in the unstable state; the bearing acceleration and loading stage, the cage is subjected to the joint action of the rolling body and the guide ring, and the increase of speed or thrust will aggravate the rubbing of the cage and the ring guide surface and the rolling body.
Based on the working conditions of high speed, heavy load and high temperature of aero bearing, the calculation model of working clearance of bearing in consideration of coordination, working temperature and high speed centrifugal load is established. The working clearance of bearing and its effect on bearing performance in different working conditions are analyzed. The model and analysis results provide guidance for the design of shaft bearing with parameters.
The dynamic performance analysis software of rolling bearing is developed by the software integration technology and the hybrid programming of Visual Basic and Matlab. The software function proves the accuracy of the model and square method by comparing the calculation results of the typical examples with the SHABERTH software and the ADORE software, indicating that the software is stable in the bearing. Two aspects of state dynamic parameter prediction and bearing transient kinematic prediction have good accuracy.
Based on the fatigue life calculation method considering the contact load of the bearing micro area, the parameter optimization model of bearing structure is established, which takes the fatigue life as the objective function, the cage sliding rate, the inner and outer ring groove curvature coefficient and the ball filling angle as the constraint conditions. The influence of the bearing structure parameters on the bearing stability is analyzed. The relative rotation of the inner and outer ring of the bearing is studied. The analysis results provide a theoretical basis for prolonging the life of aeroengine bearings.
In view of the dynamic coupling characteristics of the high-speed bearing rotor system, a coupling dynamic analysis model of the bearing rotor system is established. The effect of the rotor on the bearing dynamics is preliminarily analyzed. The contact stress between the rolling body and the ring caused by the rotor vibration and the increase of relative sliding will have a bad effect on the fatigue life and temperature rise of the axle bearing. The results provide a basis for further studying the microscopic failure behavior of the contact microzone of heavy friction pairs.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：V232;TH133.33

【参考文献】