沙粒碰撞平板模型的数值仿真研究

发布时间：2018-09-09 19:52

【摘要】：飞机在起飞、着落时,进入发动机的空气含有的尘土、砂石、杂草和冰雪等异物颗粒,而这些异物颗粒进入发动机时,将有可能造成发动机故障,直接影响发动机的可靠性和使用寿命,并间接影响飞机的综合作战能力和飞行安全。本文结合国内外关于粒子碰撞的实验研究及数值计算分析方面的研究成果,借助现代先进的计算方法,针对不同碰撞环境因素的影响下,沙粒与平板碰撞的反弹特性问题,进行讨论和研究,旨在建立完善、可靠的碰撞模型及全面的反弹特性数据库,并取得了一些有用的结论,从而了解沙粒在风扇通道或粒子分离器中的碰撞特性,为指导发动机设计提供依据。首先将沙粒与壁面的碰撞简化为球状粒子与平板的碰撞过程。利用LS-Prepost前处理器建立几何模型、划分网格并设置计算参数。通过ANSYS Mechanical Launcher启动求解器进行碰撞仿真计算。利用LS-Prepost后处理器导出计算结果,并得到了初始条件对反弹特性的影响规律,基于能量分析法和牛顿定律对这些规律进行了分析。初始条件主要包括沙粒的入射速度、角度、密度、平板的材料和平移速度。反弹特性主要包括碰撞时间、沙粒的滑移距离、反弹速度和角度。平板材料分为金属材料和复合材料,两类材料研究思路相同但本构方程不同。其中金属材料有三种,分别为410Steeel、Ti-6Al-4V和2024Al,复合材料为国防工业用橡胶。金属材料为本文研究的重点。将整理后的计算结果导入到数据库,得到反弹特性数据库基础表,以及金属平板移动影响因子的子表。以VC++为平台编写程序,与数据库结合后利用插值法计算出指定初始条件下沙粒的反弹特性。通过实验测定了沙粒碰撞铝合金板和钛合金板时入射角度和反弹角度之间的关系,得到的实验结果与数值仿真的结果误差在合理范围内,从侧面说明了该数值仿真方法的可行性。
[Abstract]:When the plane takes off and lands, the air entering the engine contains particles of foreign matter, such as dust, sand, weeds, and ice and snow, which may cause engine failure when they enter the engine. It directly affects the reliability and service life of the engine, and indirectly affects the integrated combat capability and flight safety of the aircraft. In this paper, with the help of modern advanced calculation methods and combined with the experimental research and numerical analysis of particle collisions at home and abroad, the rebound characteristics of sand particles and flat plates under the influence of different impact environment factors are discussed. The purpose of the discussion and research is to establish a complete and reliable collision model and a comprehensive database of rebound characteristics, and to obtain some useful conclusions to understand the impact characteristics of sand particles in fan channels or particle separators. It provides basis for guiding engine design. Firstly, the collision between sand particles and wall is simplified as the collision process between spherical particles and flat plates. The geometry model is built by using the LS-Prepost preprocessor, the mesh is divided and the calculation parameters are set up. The collision simulation is carried out by ANSYS Mechanical Launcher startup solver. The calculation results are derived by using the post-processor of LS-Prepost and the laws of the effect of initial conditions on the rebound characteristics are obtained. These laws are analyzed based on the energy analysis method and Newton's law. The initial conditions mainly include the incident velocity, angle, density, plate material and translational velocity of sand particles. Rebound characteristics mainly include impact time, sand slip distance, rebound velocity and angle. Plate materials can be divided into metal and composite materials. The two kinds of materials have the same research ideas but different constitutive equations. Among them, there are three kinds of metal materials, 410Steeeler Ti-6Al-4V and 2024Al. the composite is used as rubber for national defense industry. Metal material is the focus of this paper. The calculated results are imported into the database to get the basic table of the rebound characteristic database and the sub-table of the influence factor of metal plate movement. In this paper, a program is written on the platform of VC. After combining with the database, the rebound characteristics of sand particles under specified initial conditions are calculated by using interpolation method. The relationship between incident angle and rebound angle of impact of sand particles on aluminum alloy plate and titanium alloy plate is measured experimentally. The error between the experimental results and the numerical simulation results is within a reasonable range. The feasibility of the numerical simulation method is illustrated from the side.
【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】：2016
【分类号】：V263.3

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