离心压缩机失谐叶轮动力学特征

发布时间：2018-03-12 09:06

本文选题：离心压缩机　切入点：裂纹　出处：《大连理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：离心压缩机在国民经济和工业生产的许多领域中一直占有举足轻重的地位。叶轮是离心压缩机非常重要的机构,其动力特性的优劣直接影响压缩机是否安全平稳的运行,而叶轮上的叶片在高速转动的过程中由于本身制造的微小差异和外部环境等因素的影响,会逐渐产生细微裂纹,这种叶片特性的微小变化(即失谐)可能会使叶片产生较大的受迫振动,应力也会明显增加,增加的应力可能会导致结构强度的破坏,加速离心压缩机的老化破损。这种失谐所诱发的事故在旋转类机械事故中经常出现。本文通过建立质量弹簧模型来模拟离心压缩机叶轮的动力学特性,建立动力学方程后,根据方程来推导两种裂纹不同深度时叶轮上的叶片所对应的刚度,寻找其中的变化规律。然后,利用ANSYS建立叶轮的有限元模型,得到了无裂纹叶片的刚度和叶片之间的耦合刚度。最后,通过适当简化,利用AMESim软件建立了与实际模型相对应的集中参数模型,同时在时域和频域中进行相应的计算。本文最后归纳总结了裂纹深度、裂纹组合、耦合刚度等对于系统固有频率及振动响应的影响,其中裂纹深度对叶轮固有频率及振幅影响显著,分析结果对于进一步根据模态及振动响应判断离心压缩机叶轮损伤提供了理论依据。
[Abstract]:Centrifugal compressor has been playing an important role in many fields of national economy and industrial production. Impeller is a very important mechanism of centrifugal compressor. In the process of high speed rotation of the blade on the impeller, due to the small difference of the blade made by itself and the influence of the external environment and other factors, the slight cracks will be gradually produced in the process of rotating the impeller at high speed. A slight change in the blade characteristics (i.e. detuning) may cause a larger forced vibration of the blade and a significant increase in the stress, which may lead to the destruction of the structural strength. Aging and breakage of accelerated centrifugal compressor. Accidents caused by detuning often occur in rotating mechanical accidents. In this paper, the mass spring model is established to simulate the dynamic characteristics of the impeller of centrifugal compressor. After the establishment of the dynamic equation, the stiffness of the blade on the impeller with two kinds of cracks at different depths is deduced according to the equation. Then the finite element model of impeller is established by using ANSYS to obtain the stiffness of crack free blade and the coupling stiffness between blades. The lumped parameter model corresponding to the actual model is established by using AMESim software, and the corresponding calculation is carried out in the time domain and the frequency domain at the same time. Finally, the effects of crack depth, crack combination and coupling stiffness on the natural frequency and vibration response of the system are summarized, among which the crack depth has a significant effect on the inherent frequency and amplitude of the impeller. The results provide theoretical basis for judging impeller damage of centrifugal compressor according to modal and vibration response.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH452

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