动力对全机水滴收集率的影响计算

针对飞机在飞行中遭遇过冷水滴撞击并结冰现象,建立了适合于发动机带动力情况下结冰过程水滴收集率计算的三维数值方法和计算程序.其基本思路为:采用多块技术与SIMPLE方法计算空气流场,以流场分布的计算结果为基础,求解水滴相的控制方程,进而获得物体表面的水滴收集率.空气相控制方程和水滴相控制方程均写成典型输运方程的形式,采用一致的有限体积法离散求解,方便了计算程序的编制.对某型运输机巡航构型有/无动力条件的水滴收集率进行了比较计算,获得了不同直径水滴在飞机表面的撞击特征以及水滴收集率在飞机机翼、平尾、垂尾和发动机进气道唇口上的分布规律.研究表明:(1)发动机是否带动力对机翼、平尾、垂尾的水滴收集率基本无影响;(2)飞机带动力主要影响发动机进气道唇口处的水滴收集率,带动力后唇口的收集率比无动力情况高,水滴撞击范围增大,在进行防除冰研究和设计时需引起重视.

Numerical simulation of thrust effect on droplet collection efficiency in airplane icing

A three dimensional numerical method for the calculation of the droplet collection efficiency in the process of icing for an airplane with thrust is presented.The flowfield of air is computed by multiple blocks grid and SIMPLE method based on the obtained distribution,the governing equations of water phase are solved, and then the droplet collection efficiency is obtained.Both governing equations of gas and water phase are written in the form of typical transport equations, and are solved with a same finite volume method, which makes the development of numerical code easier.The droplet collection efficiency on a transport airplane cruise configuration with thrust or without thrust is computed, and the impingement characteristics of different diameter droplets are obtained, then the distribution of droplet collection efficiency on the airplane are yielded.The results show that the thrust effect of airplane on droplet collection coefficient on the wing,the vertical tail and the stabilizer is not obviously and can be ignored.However,the main effect of airplane with thrust on droplet collection coefficient occurs on the leading edge of the nacelle.The collection efficiency of airplane with thrust is higher than that without thrust on the leading edge of the nacelle,the droplet impact range of airplane with thrust is bigger than that of no thrust.