共轴式涵道无人机双桨布局气动特性研究

摘要

Irrational double-propellers arrangement in coaxial ducted fan UAV will intensify airflow's escape,resuiting in insufficient lift of UAVs and serious effect on its flight performance.In order to optimize the layout of propellets,improve aerodynamic performance of UAV,the and select RNG k-e turbulence model,the CFD simulation analysis is carried out in view of two-bladed layout's effect on aerodynamic performance of the coaxial twin-screw ducted fan UAV based on fluent software by using SIMPLE algorithm.It is found that increaseing propeller separation space can improve the lift provided by up propeller and down propeller,but when the space is too large,propellers are close to dueted import and export,which causes the suction inlet airflow loss and outlet airflow escape,affects its performance.When the space is fixed and the down propeller moves toward the ducted outlet,the lift force increases and then decreases,and effect of change in up propeller position of lift force can be ignored.By analyzing the influence of different parameters on the layout of the UAV aerodynamic performance,it can provide reference for structural optimization design.%涵道双桨布局不合理会加剧气流逸散,导致无人机升力不足,严重影响飞行性能.为了优化双桨布局,提高无人机气动性能,选择RNG k-e湍流模型,在Fluent软件中采用SIMPLE算法研究了共轴式涵道无人机双桨的布局方式对气动性能的影响.结果表明,双桨桨距增大可以提升双桨升力,但桨距过大时双桨靠近涵道进出口,造成人口吸流损失和出口尾流逸散,影响性能降低;固定桨距下桨出口方向移动时,升力呈先增大后减小的趋势,上桨位置变化对升力的影响可以忽略.结果表明通过分析不同布局参数对无人机气动性能的影响,可为气动特性优化设计提供了参考.