涡扇发动机低压转子系统振动特性研究

发布时间：2018-04-27 12:19

本文选题：涡扇发动机 + 低压转子系统　；参考：《大连理工大学》2016年硕士论文

【摘要】：近年来,出于国家安全和经济长远发展的考虑,国家对航空发动机的研发越来越重视。“航空发动机与燃气轮机”国家科技重大专项的设立,标志着国家将集中各方面的力量在这一领域寻求突破。低压转子系统是涡扇发动机的重要组成部分,跨距大,质量分布不均,转速高,并采用套齿联接结构联接风扇转子和低压涡轮转子实现动力传输,联接结构依赖具有小间隙的套齿和定位面传递力、扭矩或弯矩,使得联接呈现区间或间隙等非线性特征；由于联接的非线性及转子自身的特殊结构,使得转子系统存在振动突出、振动敏感、振幅不稳,临界转速波动或漂移等问题。本文拟以先进涡扇发动机为研究对象,针对低压转子系统含套齿联接结构开展研究工作。本文主要研究内容和结论包括：1.针对涡扇发动机低压转子的套齿联接结构中的圆柱定位面,推导圆柱接触面周向接触间隙的表达式。然后通过对Hertz接触理论和GW粗糙平面接触模型进行分析,建立了圆柱接触面接触刚度模型。通过仿真得到不同接触力、装配间隙、圆柱接触长度、表面粗糙度等对圆柱接触刚度的影响,并通过实验进行了验证,为低压转子系统建模提供联接结构模型依据。研究结果表明：随着接触力的增加,接触距离减小、接触刚度增加；当接触力较大时,接触刚度变化放缓。小间隙下,接触距离和接触刚度随接触力变化较为敏感；大间隙下,接触距离和接触刚度几乎不随间隙而改变。2.以具有代表意义的涡扇发动机的低压转子系统为对象,考虑了支承结构的弹性特点,并计入套齿联轴器内外两部分的相对运动,研究基于柔度分析的复杂转子系统动力学的建模方法,获得二自由度解析动力学模型,并应用有限元仿真和实验进行了验证。3.基于有限元方法,建立低压转子系统的少自由度有限元动力学模型,采用基于Matlab的动力学求解程序,采用Newmark逐步积分法,研究了低压转子系统的固有特性、不平衡响应及振动敏感性。4.设计并搭建了涡扇发动机低压转子原理实验台,并利用高精度激光对中仪对实验台进行对中调试,使得各支点间的不对中量都控制在合理范围内；对尾部支点进行了动平衡,使得其水平向振动幅值降低了68%,竖直向振动幅值降低了35%；并对基本动力学特性进行了实验测试和分析,对理论分析、数值仿真和实验结果进行了综合对比验证。研究结果对于涡扇发动机转子系统结构设计提供了一种简洁的解析模型,并为其振动控制、故障诊断等提供了参考。
[Abstract]:In recent years, due to the consideration of long-term development of national safety and economy, the country pays more and more attention to the research and development of aeroengine. The establishment of the National Science and Technology Project of Aeroengine and Gas Turbine indicates that the country will concentrate all its efforts to seek a breakthrough in this field. Low pressure rotor system is an important part of turbofan engine, with large span, uneven mass distribution and high rotational speed. The connection structure depends on the transmission force, torque or bending moment of the sleeve teeth and the positioning surface with small clearance, which makes the connection show nonlinear characteristics such as interval or clearance. Because of the nonlinearity of the connection and the special structure of the rotor itself, The rotor system has many problems, such as prominent vibration, sensitive vibration, unstable amplitude, critical speed fluctuation or drift, etc. In this paper, the advanced turbofan engine is taken as the research object. The main contents and conclusions of this paper include: 1. The expression of the circumferential contact clearance of the cylindrical contact surface is derived for the cylindrical positioning surface in the sleeve tooth connection structure of the low-pressure rotor of the turbofan engine. Then the contact stiffness model of cylindrical contact surface is established by analyzing Hertz contact theory and GW rough plane contact model. The effects of different contact force, assembly clearance, cylindrical contact length and surface roughness on the contact stiffness of the cylinder are obtained by simulation. The experimental results are verified to provide the basis of the connection structure model for the modeling of low-voltage rotor system. The results show that the contact distance decreases and the contact stiffness increases with the increase of contact force, and the change of contact stiffness slows down when the contact force is larger. The contact distance and stiffness are more sensitive to the contact force under small gap, and the contact distance and stiffness almost do not change with the gap in large gap. Taking the low-pressure rotor system of the turbofan engine of representative significance as an object, the elastic characteristics of the supporting structure are considered, and the relative motion of the inner and outer parts of the sleeve coupling is taken into account. The dynamic modeling method of complex rotor system based on flexibility analysis is studied, and the analytical dynamic model of two degrees of freedom is obtained, which is verified by finite element simulation and experiment. Based on the finite element method, the finite element dynamic model of low-pressure rotor system is established. The inherent characteristics of low-pressure rotor system are studied by using the dynamic solution program based on Matlab and Newmark step by step integration method. Unbalanced response and vibration sensitivity. 4. This paper designs and builds the experimental platform for the principle of low-pressure rotor of turbofan engine, and makes use of high-precision laser centering instrument to adjust the test table, so that the misalignment between the fulcrum points is controlled within a reasonable range, and the tail fulcrum is dynamically balanced. The horizontal vibration amplitude and vertical vibration amplitude are reduced by 68 and 35, and the basic dynamic characteristics are tested and analyzed. The theoretical analysis, numerical simulation and experimental results are compared and verified. The results provide a concise analytical model for the rotor system structure design of turbofan engine and provide reference for vibration control and fault diagnosis.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V235.13

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