二维翼型积冰生长过程的数值模拟计算

发布时间：2018-07-28 06:57

【摘要】：随着我国科学技术与国民经济的高速发展，飞机作为必要的交通工具进入了人们的生活，已经成为人们生活的一部分。飞机给人们带来方便、快捷和舒适的生活，也带来了一定的风险，飞行安全时刻敲醒警钟。其中，飞机结冰造成的飞行风险占据显著地位，已经成为危害飞行安全的头号因素。飞机在穿过云层飞行的过程中，当遇到结冰气象条件时，会在机体表面就会形成积冰。这些结冰云层里面存在着未冻结的液态小水滴，他们分布在云层里面，当飞机高速穿过结冰云层时，这些小水滴与飞机发生碰撞，打破了他们原来保持的稳定，部分液态小水滴就会瞬间变成细小的冰颗粒，附着在翼型表面上，使得飞机出现结冰现象。飞机结冰是伴随着蒸发、对流、摩擦、热传导、气动加热等一系列的质量和能量变化的复杂过程。本文介绍了与飞机结冰相关的一些基本概念，简要概括了结冰对飞机飞行性能和操纵性能等方面的影响。概括了飞机结冰现象的一些研究方法。应用Fluent软件求解二元翼型周围的绕流情况，应用求解偏微分方程的方法对二维翼型进行网格划分，利用翼型算例对流场的算法进行了验证。研究了水滴在流场中的运动情况，阐述了水滴冲击翼型的相关概念，特别分析了水滴撞击特性的影响因素，应用Lagrange法建立了水滴的运动方程，根据数值求解的方法（Runge-Kutta），得到了翼型上下表面水滴的撞击极限，进而得到水滴的运动轨迹。建立了二维翼型的Messinger结冰数学模型，根据假设建立并求解了翼型表面的质量平衡方程和能量守恒方程，考虑了结冰表面粗糙度对翼型结冰的影响，给出了翼型表面积冰形状的确定方法。最后对NACA0012翼型的三个结冰算例进行了数值模拟计算，将模拟的结果与实验给出的结果展开比较分析，结果基本符合实验结果中积冰生长趋势，证明了本文算法是有效的和可行的，同时，从对升力与阻力方面的影响出发，简要说明了翼型表面结冰后气动特性的改变。
[Abstract]:With the rapid development of science and technology and national economy in China, aircraft, as a necessary means of transportation, has become a part of people's life. Aircraft brings people a convenient, fast and comfortable life, but also brings certain risks. Among them, the flight risk caused by aircraft icing occupies a prominent position and has become the number one factor that endangers flight safety. As the plane travels through the clouds, ice accumulates on the body's surface when it encounters icy weather conditions. There are small, unfrozen droplets of liquid water in these frozen clouds, and they are distributed in the clouds, and as the plane passes through the frozen clouds at high speed, the droplets collide with the plane, disrupting the stability they once maintained. Some small liquid droplets will instantly become small ice particles, attached to the surface of the airfoil, causing the aircraft ice phenomenon. Aircraft icing is a complex process of mass and energy changes, such as evaporation, convection, friction, heat conduction, aerodynamic heating, etc. In this paper, some basic concepts related to aircraft icing are introduced, and the effects of icing on aircraft flight performance and maneuverability are briefly summarized. Some research methods of aircraft ice phenomenon are summarized. The flow around a binary airfoil is solved by using Fluent software. The method of solving partial differential equation is used to mesh the two-dimensional airfoil, and the algorithm of flow field is verified by an example of airfoil. In this paper, the motion of water droplets in the flow field is studied, the related concepts of water droplet impingement airfoils are expounded, and the influence factors of water droplet impact characteristics are analyzed, and the equation of motion of water droplets is established by using Lagrange method. According to the numerical solution method (Runge-Kutta), the impact limit of the water droplets on the upper and lower surfaces of the airfoil is obtained, and then the trajectory of the water droplets is obtained. The Messinger icing mathematical model of two dimensional airfoil is established. The mass balance equation and energy conservation equation of airfoil surface are established and solved according to the hypothesis. The influence of icing surface roughness on airfoil icing is considered. The method of determining the ice shape of airfoil surface area is given. Finally, three ice forming examples of NACA0012 airfoil are numerically simulated and compared with the experimental results. The results basically accord with the trend of ice accumulation in the experimental results. It is proved that the proposed algorithm is effective and feasible. At the same time, the change of aerodynamic characteristics after icing on airfoil surface is briefly explained from the effect on lift and resistance.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：V328

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