【作者】 张瑞琴；

【导师】 翁建生；

【作者基本信息】 南京航空航天大学 ， 车辆工程， 2009， 硕士

【摘要】 叶轮机气动弹性力学是流固耦合问题的重要分支。流场作用在弹性结构叶片上会产生气动力,气动力使得叶片振动产生变形,结构的变形又会改变流场分布,从而产生新的作用力。当振幅不断增加时,叶片就会产生颤振。本文对平板叶栅进行气动弹性稳定性试验研究,观察到颤振过程,分析了叶片颤振时叶尖上方壁面处压力脉动与叶片振动之间的关系。在对流固耦合原理和数值模拟求解过程进行详细分析的基础上,研究如何使用流体力学软件CFX,结构有限元分析软件ANSYS和两者间的耦合平台进行流固耦合计算。并应用这种方法对试验用平板叶片进行气动弹性数值模拟,得到叶片在不同来流速度下的位移响应和压力脉动响应,与试验结果进行对比,说明了这种方法的可行性。应用同样方法研究了NACA0012直叶片的气动弹性稳定性,得到其关于攻角和来流马赫数的颤振边界,并得出以下结论:叶尖上方壁面处静压响应与振动位移响应的变化趋势相同,并且压力脉动频率与颤振频率一致,均接近叶片的固有频率,这为叶片颤振预测提供了一种新思路。最后,对压气机转子叶片进行气动弹性数值仿真模拟,分析了定常流场特性、叶片耦合振动特性和叶片的动应力。本文所得到的叶片流固耦合问题数值计算方法研究和数值分析的结果,对预测叶片颤振和叶片气动弹性分析有参考价值。更多还原

【Abstract】 The research for turbo-machinery aero-elasticity is an important part of the study of fluid solid coupling. Aero-elasticity is the phenomenon which exhibits distinct reciprocal interactions between aerodynamic force on blades and vibration deformation. Flutter will occur when vibrating amplitude of blades increases continually.In this paper, aero-elasticity stability experiment of a flat plate cascade is carried out. Flutter process is observed and relationship between wall pressure response on top of blade tip and vibrating response of the blade is analyzed. Exhaustive analysis of fluid solid coupling and the process of numeric simulation are presented here. A numeric simulation approach by using CFX, ANSYS and a coupling platform between the two soft wares was applied for studying the fluid solid coupling. The aero-elasticity stability of the flat blade used in the above experiment is simulated using the approach. With different inlet velocities, displacement and pressure response are obtained. Feasibility of this approach is testified by comparing the calculation results with experiment results. Meantime, aero-elasticity stability of NACA0012 straight blade is also simulated by using the same approach. Flutter boundaries of the blade are acquired by correlating attack angle with inlet Mach number. And following conclusions are reached: changing trend of fluid pressure response on top of the blade is consistent with vibrating response of the blade. And both of the response frequencies are the same, which are fairly close to natural frequency of the blade. This provides a new idea of blade flutter prediction. In the end, aero-elasticity stability of compressor rotors is simulated. Steady fluid field characteristic,the vibrating characteristic and stress of the blade are analyzed.In this paper, fluid solid coupling simulation of blades and calculation results are useful for reference on blade flutter prediction and aero-elasticity analysis.更多还原