硬物对发动机风扇叶片损伤规律的仿真研究

发布时间：2018-10-13 14:35

【摘要】：在发动机风扇叶片外物损伤研究中,为获得硬物初次撞击到风扇叶片的数据及撞击后叶片损伤凹坑的深度和宽度。本文借助计算流体动力学模拟技术模拟不同初始条件下硬物在发动机流场中从地面起动至初次撞击到风扇叶片的运动轨迹,并获得撞击到风扇叶片上的位置、速度以及方向,进而建立硬物撞击风扇叶片的碰撞模型,模拟不同初始条件下硬物对发动机风扇叶片损伤产生凹坑的深度与宽度,具体研究方法如下:(1)通过分析硬物的物理性质,根据牛顿第二定律对硬物在流场中运动时进行受力分析,建立硬物运动的微分方程,通过积分求解获得硬物在流场中?t后位置坐标的迭代公式,根据迭代公式以及流场内任意点的气动参数计算确定硬物吸入发动机的运动轨迹;对硬物撞击风扇叶片速度进行估算,得出硬物撞击风扇叶片的速度估算值。(2)建立了发动机整级风扇叶片、轮毂、整流罩以及发动机气体流场的三维几何模型,对流场进行仿真并获得了气体流场仿真模型,再采用颗粒离散相模型对硬物在流场中的运动轨迹进行仿真。通过改变硬物在流场中的初始条件来获得硬物吸入发动机的不同运动轨迹图以及撞击到风扇叶片上的位置、速度和方向。(3)建立了硬物撞击风扇叶片的计算模型,确定材料参数并进行了大量的碰撞动态仿真。分析硬物撞击发动机风扇叶片进气边损伤产生凹坑的尺寸与硬物撞击叶片速度、直径、密度以及撞击风扇叶片位置的关系。仿真结果表明:尽管硬物在流场中的初始位置相差较多,但吸至进气道口时几乎已为相同位置,撞击到风扇叶片的位置都比较集中,大多集中在YOZ截面中心线下方靠近叶尖位置。硬物对发动机风扇叶片进气边损伤产生凹坑的尺寸与硬物直径、密度、撞击叶片相对速度的增加呈一定的线性关系,可以认为随着凹坑深度的增大,凹坑宽度也随之变大,不过凹坑的宽深比有略微增大的趋势。仿真结果为航空发动机风扇叶片的损伤试验提供理论依据。
[Abstract]:In order to obtain the data of the first impact of the hard object on the fan blade and the depth and width of the damage pit of the blade after the impact, the external damage of the engine fan blade is studied. In this paper, by means of computational fluid dynamics simulation technique, the motion track of hard objects in different initial conditions from ground start to initial impact to fan blade is simulated, and the position, velocity and direction of impact on fan blade are obtained. Then, the impact model of hard object impingement fan blade is established, and the depth and width of crater caused by hard object damage to fan blade under different initial conditions are simulated. The specific research methods are as follows: (1) by analyzing the physical properties of hard object, According to Newton's second law, the force of hard object in flow field is analyzed, the differential equation of hard object motion is established, and the iterative formula of the position of hard object in flow field after t is obtained by integral solution. According to the iterative formula and the aerodynamic parameter calculation of any point in the flow field, the motion track of the hard object suction engine is determined, and the velocity of the hard object impinging on the fan blade is estimated. The velocity estimation of the rigid object impingement fan blade is obtained. (2) the three-dimensional geometry model of the whole stage fan blade, hub, fairing and engine gas flow field is established, the flow field is simulated and the simulation model of the gas flow field is obtained. Then the particle discrete phase model is used to simulate the motion trajectory of hard objects in the flow field. By changing the initial conditions of the hard object in the flow field, the different motion trajectories of the hard object suction engine and the position, velocity and direction of impingement on the fan blade are obtained. (3) the calculation model of the hard object impinging on the fan blade is established. Material parameters are determined and a large number of dynamic collision simulations are carried out. The relationship between the size of the crater and the velocity, diameter, density and the position of the impingement fan blade is analyzed. The simulation results show that although the initial position of the hard object in the flow field is quite different, it is almost in the same position at the inlet of the inlet, and the position of impingement on the fan blade is relatively concentrated. Most of them are located near the tip of YOZ section. The size of the crater caused by the damage of the inlet edge of the engine fan blade is linearly related to the increase of the relative velocity of the rigid object, the density and the relative velocity of the impingement blade. It can be concluded that with the increase of the depth of the pit, the width of the pit also increases. However, there is a slight increase in the width to depth ratio of the pit. The simulation results provide the theoretical basis for the damage test of the fan blade of aero-engine.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V232.4

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