航空电机自冷风扇安装效应气动影响研究

Analysis on influence of self-fan cooling motor on fan aerodynamics

随着多电/全电飞机发展,飞机二次能源电气化程度越来越高。作为电气系统核心部件的电机呈现出小体积、高功率密度的趋势,紧凑电机的散热问题越发严重,自驱风扇冷却系统目前被航空电机广泛使用。以某型航空起发电机轴流风扇冷却系统为研究对象,采用三维计算流体仿真方法分析了孤立风扇以及电机安装后风扇-电机耦合模型中风扇流场和气动特性变化,同时还研究了风扇与电机轴向间距变化的气动性能影响。计算结果表明,电机与风扇部件之间的紧密耦合极大影响了风扇内的流动结构,使得风扇出口截面产生畸变势影响,风扇流场出现叶根回流和叶中通道涡以及角区分离面积扩张,并且随着电机与风扇轴向间距的增加,电机对风扇内流动的影响逐渐接近为流量堵塞效果。

With the development of multi electric/all electric aircraft,the degree of aircraft secondary energy electrification is becoming higher and higher.As the core component of the electrical system,the motor presents the trend of small volume and high-power density.The heat dissipation problem of compact motor is becoming more and more serious.At present,the self-driven fan cooling system is widely used in aircraft motors.In this paper,the axial fan cooling system of an aero generator is taken as the research object,and the changes of fan flow field and aerodynamic characteristics in the fan motor coupling model of the isolated fan and the installed motor are analyzed by using three-dimensional computational fluid simulation.At the same time,the influence of the change of the axial distance between the fan and the motor on the aerodynamic performance is also studied.The analysis of the simulation results shows that the close coupling between the motor and the fan components greatly affects the flow structure in the fan,resulting in the distortion potential effect on the fan outlet section.The fan flow field appears the blade root reflux,the channel vortex in the blade and the expansion of the corner separation area.With the increase of the axial distance between the motor and the fan,the influence of the motor on the flow in the fan gradually approaches the flow blocking effect.