【作者】 张伟；

【导师】 王艾伦； 刘排秧；

【作者基本信息】 中南大学 ， 机械（专业学位）， 2023， 硕士

【摘要】 航空发动机燃发转子长期服役于较为复杂的高温、高压、高转速等环境下。由于初始的制造、安装误差以及长期运行后的热变形、摩擦磨损等原因,燃发转子系统不对中问题广泛存在,不对中会引起转子系统振动加剧、油膜偏心率变大以及轴挠曲变形加剧等一系列问题,危害极大。以往关于燃发转子不对中的研究往往忽略了端齿连接结构、弹性支承和挤压油膜阻尼器组合支承等因素,难以满足真实燃发转子不对中振动特性的研究需求。因此,本文以某型涡轴发动机燃发转子为研究对象,开展组合支承-端齿连接燃发转子支点不对中振动特性研究,为涡轴发动机转子系统设计、装配及不对中振动控制提供一定的理论依据和工程指导。主要研究内容及成果如下:(1)对端齿连接结构进行了等效处理,得到了考虑端齿接触效应的端齿等效环材料参数,然后基于Timoshenko梁单元理论建立了对中状态下端齿连接转子动力学模型,并通过有限元软件和实验方法验证了所建模型的准确性,为后文的研究提供了模型基础。通过计算发现当考虑端齿接触效应时,各阶共振转速及峰值都会发生较为明显的变化,研究转子振动特性时不能忽略端齿连接结构的影响。(2)基于上述所建模型,引入转子系统后支点不对中,推导出和支承刚度、考虑端齿连接的转子结构刚度以及支点不对中量相关的支点不对中激励,建立了考虑端齿连接转子挠曲变形的支点不对中动力学模型,得到了端齿连接转子后支点不对中的振动特性,结果表明:支点不对中会使转子出现新的2倍频分量,且会导致在约1/2倍一阶共振转速下出现新的峰值;当后支点不对中量小于150μm时对转子动力学响应的影响较小。研究了不平衡分布对转子支点不对中动力学响应的影响规律,发现不平衡轴向和周向位置的变化2倍频分量的影响很小,主要对1倍频分量大学产生影响。(3)依据π油膜假设和短轴承理论,得到考虑支点不对中因素的非线性挤压油膜力,建立了组合支承-端齿连接转子支点不对中动力学模型,分析了支承刚度对端齿连接转子支点不对中动力学响应的影响规律以及支点不对中量对油膜减振效率的影响规律,最终得到本文转子在满足航空发动机挤压油膜阻尼器偏心率<0.4的设计标准下,后支点的不对中量最大限制值为350μm。图63幅,表8个,参考文献77篇更多还原

【Abstract】 Aero-engine combustion rotors have been in service for a long time in a complex environment of high temperature,high pressure and high speed.Due to initial manufacturing and installation errors,as well as thermal deformation and frictional wear after long-term operation,misalignment of the combustion engine rotor system is a widespread problem,causing a series of problems such as increased rotor system vibration,larger oil film eccentricity and increased shaft deflection and deformation.Previous studies on the misalignment of combustion engine rotors have often ignored factors such as the end-tooth connection structure,elastic support and the combined support of extruded oil film dampers,which make it difficult to meet the research needs of real combustion engine rotor misalignment vibration characteristics.Therefore,this thesis takes a certain type of turboshaft engine combustion rotor as the research object and carries out the research on the misalignment vibration characteristics of combustion rotor pivot point with combined support-end gear connection,so as to provide some theoretical basis and engineering guidance for the design,assembly and misalignment vibration control of turboshaft engine rotor system.The main research contents and results are as follows:(1)The end-tooth connection structure was equated to obtain the end-tooth equivalent ring material parameters considering the end-tooth contact effect,and then a model of the end-tooth connection rotor dynamics in the centered state was established based on Timoshenko beam cell theory.It is found that when the end-tooth contact effect is considered,the resonance speed and peak value of each order will change significantly.(2)Based on the above-mentioned model,a pivot point misalignment excitation related to the pivot point stiffness,the rotor structural stiffness considering the end-tooth connection and the amount of pivot point misalignment is derived,and a pivot point misalignment dynamics model considering the end-tooth connection rotor flexural deformation is established.The results show that the misalignment of the pivot point causes a new 2-fold frequency component in the rotor and leads to a new peak at approximately 1/2 times the first order resonance speed;the effect on the dynamic response of the rotor is small when the rear pivot misalignment is less than 150 μm.The effect of the unbalance distribution on the dynamic response of the rotor pivot misalignment was investigated and it was found that changes in the axial and circumferential position of the unbalance have little effect on the 2-frequency component and mainly on the 1-frequency component of the university.(3)Based on the π oil film hypothesis and short bearing theory,the nonlinear squeeze oil film force considering the misalignment of the pivot point is obtained,and a combined bearing-end tooth connection rotor pivot point misalignment kinetic model is established.The maximum limit of misalignment of the rear pivot point is 350μm under the design standard of eccentricity ε<0.4 of the damper.更多还原