叶片流固耦合振动分析方法研究

发布时间：2018-05-09 01:32

本文选题：平板叶片 + 流固耦合　；参考：《南京航空航天大学》2012年硕士论文

【摘要】：在叶轮机械中,引起叶片振动的因素很多。其中作用在叶片上的流体扰动力是激发振动的最重要因素。在叶片振动过程中,一般通过分析坎贝尔图来预测叶片工作时的共振状态,但是在航空发动机工作范围内仅仅依靠坎贝尔图中的几个共振点来判断发动机工作中出现的危险状况及共振现象是远远不够的,在共振点外的工作区域,发动机叶片仍会有振动现象,因此只能通过分析作用于叶片致使其产生振动的气体激振力才是最有效的方法,直接求解并控制叶片的振动响应(位移和应力),从而分析造成叶片破坏的因素。叶片周围存在着气体,而这些气体力的分布情况决定着叶片振动时的速度、位移的变化规律,然而叶片振动过程中又会影响到叶片周围气体力的分布,促使流场中的结构体发生形变。因此必须把气体和结构体两个相互影响因素考虑进去,才能准确把握叶片真实振动的细节问题。本文在总结气弹动力学研究方法的基础上,重点研究了基于多步流固耦合下气体激振力预测方法及以Workbench/CFX为仿真工具,运用多步耦合的方法对平板叶片进行了振动响应分析。主要具体工作内容如下： 1)提出了一种流固耦合下叶片气体激振力预测方法。以平板叶片为研究对象,对有静子平板叶片时的转子平板叶片、无静子平板叶片时的转子平板叶片以及其周围的流体域进行建模,来模拟尾流激振的情况,利用Workbench和CFX仿真计算软件,进行流固耦合的数值模拟计算,得到平板叶片表面气动力收敛情况下的值,根据所得气动力值与叶片形变的关系建立最终稳定时尾流激振下激振力的表达式。 2)在建立最终尾流激振力表达式的基础上,研究了流固耦合下叶片强迫振动分析方法,并对考虑流固耦合与不考虑流固耦合下转子平板叶片的的强迫振动响应计算结果进行对比与分析。 3)调整静子叶片前的进气角,对流固耦合下转子平板叶片进行了谐响应分析,获得了在不同进气角下平板叶片振动响应的变化规律。 4)在上述研究的基础上,分析了流固耦合下静子叶片进气角对转子叶片动力稳定性的影响。
[Abstract]:In impeller machinery, there are many factors causing blade vibration. The fluid disturbance force acting on the blade is the most important factor to excite vibration. In the process of blade vibration, the resonance state of blade is usually predicted by analyzing Campbell diagram. However, it is far from enough to judge the dangerous condition and resonance phenomenon in the work of the aeroengine only by several common vibration points in Campbell diagram, and the working area outside the common vibration point is far from enough. There is still vibration in the blade of the engine, so the most effective method is to analyze the gas excitation force that causes the blade to vibrate. The vibration response (displacement and stress) of the blade is directly solved and controlled, and the factors causing the blade failure are analyzed. There are gases around the blade, and the distribution of these gas forces determines the speed and displacement of the blade vibration, but the blade vibration process will affect the distribution of the gas force around the blade. Causes the structure in the flow field to deform. Therefore, gas and structure must be taken into account in order to accurately grasp the details of the real vibration of the blade. On the basis of summarizing the research methods of aero-elastic dynamics, this paper focuses on the prediction method of gas excitation force based on multi-step fluid-solid coupling and the vibration response analysis of flat plate blade using Workbench/CFX as simulation tool. The main contents of the work are as follows: 1) A prediction method of blade gas excitation force under fluid-solid coupling is proposed. Taking flat blade as research object, the rotor plate blade with stator blade, rotor plate blade with no stator blade and its surrounding fluid domain are modeled to simulate the wake induced vibration. By using Workbench and CFX software, the numerical simulation of fluid-solid coupling is carried out, and the results of aerodynamic convergence on the surface of flat blade are obtained. According to the relationship between the aerodynamic value and blade deformation, the expression of the induced force under the wake excitation is established. 2) based on the final expression of wake excitation force, the analysis method of blade forced vibration under fluid-solid coupling is studied. The calculation results of forced vibration response of rotor plate blade considering fluid-solid coupling and non-fluid-solid coupling are compared and analyzed. 3) by adjusting the inlet angle of the stator blade, the harmonic response of the rotor plate blade is analyzed under convection-solid coupling, and the variation law of the plate blade vibration response under different inlet angles is obtained. 4) on the basis of the above research, the influence of inlet angle of stator blade on the dynamic stability of rotor blade under fluid-solid coupling is analyzed.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH113.1

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