客机通风系统中风扇流量特性数值模拟与研究

Numerical Simulation and Research on Flow Characteristics of Fan in the Ventilation System of Airliners

风扇是飞机通风系统中的重要部件,其工作情况对环控系统的正常工作具有重要影响。以某型风扇为研究对象,在变流量条件下,采用数值模拟方法对各流量下的风扇效率、压升、功率等参数进行计算,对其变化趋势进行分析;结合叶片极限流线图和空间涡量图分析不同流量下风扇的流场情况以及不同流场结构对效率的影响。结果表明:总压效率在一定范围内会随流量增大而增加,当流量达到一定值后再增加流量会使效率急剧降低;流量的变化导致叶片表面静压力以及风扇所受气动力的变化,在低流量下,叶轮所受气动力存在一个最低点;在给定的流量范围内流场中的漩涡结构也会随流量而变化,这主要是因为流量变化引起了攻角的变化。

Fan is an important part of aircraft ventilation system,and its working condition is of an important influence on the normal operation of environmental control system.Taking a fan as the research object,under the condition of variable flow rate,the parameters of fan efficiency,pressure rise,power and so on are calculated by numerical simulation method,and the changing trend is analyzed.Combined with the limit streamline diagram and the spatial vorticity diagram,the flow field of the fan under different flow rates and the effect of different flow structures on efficiency are analyzed.The calculation and analysis show that the total pressure efficiency will increase with the increase of flow rate in a certain range,and when the flow rate reaches a certain value,the increase of flow rate will sharply reduce the efficiency.In addition,the change of flow leads to the change of static pressure on the blade surface and aerodynamic force on the fan.At low flow rate,there is a lowest point of aerodynamic force on the impeller.In a given flow range,the vortex structure in the flow field will also change with the flow,which is mainly due to the change of the angle of attack caused by the change of the flow.