基于小扰动理论的桨叶叶素气动载荷计算方法

Calculation method of blade element aerodynamic loads based on small perturbation theory

针对直升机飞行仿真应用,采用小扰动理论建立了桨叶叶素气动载荷计算方法。该计算方法集成了弹性桨叶挥舞-摆振-扭转模态,耦合了旋翼动态入流、非定常动态失速气动模型和旋翼配平模型。整个算法采用标准的状态空间格式。为验证算法,以UH-60A直升机为例,在低速和高速2种定常飞行情况下,研究了偏航流效应对旋翼气功性能的影响,结果表明高速飞行时偏航流效应对旋翼气功性能影响较大。模拟了桨盘平面诱导速度分布以及桨叶叶素气动载荷,将仿真结果与飞行试验结果进行对比验证,本文建立的方法可以准确地求解定常飞行时桨叶的非定常气动载荷,捕捉其沿方位角的变化特征,对于大速度前飞仍能适用。

A calculation method of blade element aerodynamic loads based on small perturbation theory is established for helicopter flight simulation application. The method synthesizes flap-lag-torsion elastic rotor blade mode,couples rotor dynamic inflow,unsteady aerodynamics model with dynamic stall and rotor trimming model. The entire model is developed in a standard state-space form. To verify this model,the UH-60 A helicopter is taken as an example,and the effects of yaw flow on rotor aerodynamic performance are studied at low speed flight and high speed flight. It is shown that yaw flow has a greater effect on rotor aerodynamic performance at high speed flight. Blade induced velocity fields and aerodynamic loads are simulated,and the results are compared with flight test data. It is shown by the results that the method can accurately predict the unsteady aerodynamic rotor loads in steady flight by capturing its variational characteristics along blade azimuthal locations,and it is still applicable for high speed flight.