飞机在穿越云层飞行时,云层中的过冷水滴撞击到飞机表面,会发生结冰现象,飞机结冰对飞行安全造成很大的危害,因此飞机结冰的研究历来受到世界各国的重视.飞机结冰是一个复杂的传热传质现象,涉及到流体力学、传热学以及空气动力学等多个领域,由于国内不具备冰风洞试验条件,飞机防/除冰系统设计中往往依赖于工程估算,本文采用数值模拟对飞机结冰现象进行了研究,这可以一定程度上弥补试验条件欠缺的不足,这方面的工作国内尚处于起步阶段.When an aircraft flies through the clouds, the impact of the super cooled water droplets in the clouds on the surface of the aircraft will create an ice-up phenomenon; icing on aircraft is a grave danger to aviation safety, so the research of aircraft icing has always been the world’s focus of attention. Icing on aircraft is a complex heat and mass transfer phenomenon, it involves many fields such as fluid mechanics, heat transfer, air dynamics etc. As there is a lack of icing tunnel experiment conditions in China, the prevention and deicing system designs often have to rely on engineering estimations. This paper adopts the method of numerical simulations to study the phenomenon of icing on aircraft; this can make up for the lack of testing conditions to a certain extent, and this kind of work in China is still in the infant stage.
本文的研究工作主要有以下几个方面:
1)简述了飞机结冰现象及其主要研究方法,着重介绍了飞机结冰数值模拟研究的发展状况;
2)在对发生飞机结冰现象的飞行和气象条件分析的基础上,确定了采用求解N-S 方程来计算结冰时的空气流场,选用了适用于飞机结冰研究的湍流模型.
3)对建立水滴运动方程的欧拉型方法进行了研究,在合理的假设和简化的基础上,建立了适用于飞机结冰研究的空气/过冷水滴两相流控制方程.根据飞机结冰气象条件的特点,研究了方程的求解方法.
4)对热载荷模型进行了研究,分析讨论了各个热流的求法.
5)利用本文提出的方法,进行了机翼结冰的数值模拟,通过FLUENT加载用户自定义函数(UDF),计算得到防冰表面的各项热流密度,并对其进行分析.
6)对本文的工作进行了总结The research of this paper mainly consists of the following aspects:1. It briefly describes the aircraft icing phenomenon and its major research methodology; it emphatically presents the development situation of the numerical simulation of icing on aircraft;2. Based on the analysis of flight and meteorological conditions when aircraft icing occurs, the use of solution of N-S equations is confirmed for calculating the airflow field when icing is formed, and the turbulence model suitable for the aircraft icing research is selected;3. Study is conducted on the Eulerian Method for setting up the droplet trajectory equation; the air and super cooled waterdroplet two-phase flow control equation is established on the basis of reasonable hypothesis and simplification, and based on the characteristics of weather conditions when aircraft icing occurs, the method of solving the equation is studied;4. Research is conducted on the thermal load model, and the solutions of the various heat flux are analyzed and discussed; 5. By applying the method proposed by this paper, numerical simulation of icing on the aircraft wings is conducted, and through the FLUENT loaded User Defined Function (UDF), the various heat flux densities on the surface of icing prevention are obtained, and analysis is conducted on them.6. Finally, the work of this paper is summarized.