涵道风扇外形参数对气动特性的影响

以某涵道风扇为原型,从理论上分析涵道扩张角对涵道风扇气动特性的影响。运用滑移网格模型,采用三维不可压黏性Navier-Stokes控制方程,利用SST k-ω湍流模型,计算两叶桨气动特性,并与试验结果对比,验证该方法的可行性。分别计算涵道风扇在悬停状态下,3000~8500 r/min转速范围内,涵道唇口外形、扩张角和涵道高度对气动特性的影响,并对流场进行分析。椭圆形唇口的涵道风扇总拉力系数小,气动效率低;当涵道扩张角在8.2°附近时,功率系数相对最小,随着扩张角增大,在桨盘下方靠近涵道壁面附近出现气流分离;涵道拉力系数对涵道风扇高度的变化敏感度低,随着高度增加功率系数略有下降。

The influence analysis of ducted fan profile parameters on aerodynamic characteristics

The influence of ducted fan profile parameters to aerodynamic characteristics was investigated in this paper. Firstly, it calculated the thrust produced by different part of ducted fan which was affected by diffuser angle based on the momentum theory and Bernoulli equation. At the same time, the three-dimensional incompressible viscous Navier-Stokes equations and SST k-omega turbulence model were used to simulate the complex flow of a 2-blade propeller, which was based on the sliding mesh method. To demonstrate the feasibility of the method, the result was compared with experimental data. Then, it analyzed the influence of the lip shape, diffuser angle and the height of ducted fan on aerodynamic characteristics and flow field, on the condition of hovering. The thrust coefficient produced by ducted fan with the elliptical lip was small, and its aerodynamic efficiency was very low. The power coefficient was the smallest when the diffuser angle was 8.2deg. The flow separation would emerge near the duct under the propeller disk, with the increase of diffuser angle. The sensitivity of thrust coefficient to the change ducted fan height was low. The power coefficient descended slightly with the increase of height.