【作者】 王海涛；

【导师】 罗贵火；

【作者基本信息】 南京航空航天大学 ， 航空宇航推进理论与工程， 2010， 硕士

【摘要】 发动机整机振动不仅使发动机的工作状态、发动机附件及仪表的工作状态受到影响,而且会使发动机的结构受到巨大的振动应力,影响发动机工作的可靠性。近年来,有限元计算技术和计算机技术的逐渐发展,为航空发动机整机振动特性的研究提供了必要条件。为保证航空发动机的工作安全、可靠,本文针对某型双转子航空发动机结构特点,进行了整机振动特性相关分析;从转子的临界转速特性分析、机匣振动特性分析到整机振动特性分析,开展了如下相关研究工作:第一,为了使发动机整机振动有限元模型合理可信,本文首先利用有限元理论对发动机机匣模型进行了一定的简化处理,计算了发动机机匣的振动模态及其各主支承处的静刚度与动刚度,比较了两者之间的差别。研究结果表明:由于发动机机匣在工作转速内固有模态的影响,考虑机匣及支承结构动刚度计算的转子临界转速更加合理、可靠,也表明了整机振动分析的必要性。第二,针对本文研究的航空发动机结构特点,分别分析了高、低压转子考虑机匣及其支承静、动刚度模型下的临界转速特性。第三,利用传递矩阵法计算了发动机高、低压转子临界转速,并与有限元模型进行了对比。研究结果表明:在相同支承刚度下,传递矩阵法与有限元法计算结果误差在10%以内,计算结果可信。第四,建立了某型航空发动机整机振动分析模型,进行了整机振动特性分析,分析了双转子耦合效应对系统临界转速的影响,研究了螺栓连接、不同支承刚度、不同转速比对系统临界转速的影响。研究结果表明:对于本文研究的双转子航空发动机,运用整机模型计算其转子的临界转速更加合理,其计算结果更接近于实际。更多还原

【Abstract】 The whole aero-engine vibration not only influences the working state of engine,accessories and instrument, but also brings engine structure huge vibration stress, so research on the whole body vibration of aero-engine is essential. According to the development of technology of the FEM software and computer, calculating the whole body vibration of aero-engine is becoming possible. In order to ensure aero-engine working safety and reliability, the finite element model of the whole aero-engine is built and used to analyse the whole body vibration, basing on its structural characteristic. The research work is carried out from analysis of the rotor critical speed and the vibration of casing to analysis of the whole body vibration, it is as follows:Firstly, in oreder to insure bilievable of the model of whole body aero-engine, the finite element calculation model of engine-casing is reasearched using some base theory, the static rigidity and dynamic rigidity of casing is analyzed with model. The calculating result of the critical speed of the rotor indicates that dynamic rigidity model is more reasonable than static rigidity model, owing to the caing natural modal appearing area of the working speed.Secondly, according to properties of the aero-engine structure, the characteristics of critical speeds are calculated separately adopting static rigidity and dynamic rigidity model of the low-pressure and the high-pressure rotor in the article.Thirdly, the critical speeds of the low-pressure and the high-pressure rotor are calculated with the transfer matrix method, and the calculating results are compared with the finite element model. It indicates the results of both methods are close; the errors within 10% and the calculating results reliabilities.Fourthly, the finite element model of the whole aero-engine is built and used to analyse the whole body vibration. The influence of the critical speed with the coupled effect between the dual-rotor is analyzed, and the influence with the different supporter’s stiffness、the different speed ratio and bolt connection is researched in the article. It is found that, the calculating results of the critical speeds with the whole aero-engine model are reasonable, and close to reality.更多还原