论文部分内容阅读
悬停和侧滑状态的直升机主旋翼桨尖涡将穿透尾桨桨尖平面,由此导致尾桨非定常气动载荷发生明显变化。为更准确地模拟由主旋翼/尾桨干扰产生的尾桨非定常气动载荷变化,通过在面元压力项中增加由旋翼桨尖涡诱导的时变项,体现旋翼桨尖涡速度和几何时变对桨叶非定常压力的影响,同时采用涡面镜像法修正涡粒子法的黏性项,确保桨叶附近区域旋翼涡量守恒,建立旋翼尾迹对尾桨叶的非定常气动干扰模型,并耦合面元/黏性涡粒子法,构建直升机主旋翼/尾桨干扰下的尾桨非定常气动载荷分析方法。通过计算AH-1G旋翼桨叶非定常气动载荷特性,并与实验测量值、计算流体力学(CFD)计算结果对比,验证本文非定常气动干扰模型的有效性。随后基于NASA ROBIN(Rotor Body Interaction)模型分析悬停、侧风和60°右侧滑状态主旋翼对尾桨非定常气动载荷的影响,分析表明主旋翼尾迹对尾桨非定常气动载荷影响显著。悬停状态的主旋翼/尾桨干扰导致尾桨拉力平均值下降、非定常气动载荷显著增加;左侧风状态,主旋翼/尾桨干扰削弱尾桨“涡环”程度,显著增加尾桨拉力和非定常气动载荷;60°右侧滑状态,主旋翼/尾桨干扰导致尾桨拉力损失最大,且在低速侧滑状态出现尾桨拉力“迅速恢复”现象,尾桨非定常气动载荷幅值迅速增加。
Helicopter main rotor tip hovering hovering and skidding conditions will penetrate the tail rotor tip plane, resulting in significant changes in unsteady aerodynamic loads on the tail rotor. In order to more accurately simulate the unsteady aerodynamic load changes of the tail rotor caused by the main rotor / tail rotor interference, the rotor vortex tip velocity and geometric time And the non-steady-state pressure of the rotor blades is changed. At the same time, the viscoelasticity of the vortex particle method is corrected by the method of the vortex mirror to ensure the conservation of the rotor vorticity in the vicinity of the blade, and the unsteady aerodynamic interference model of rotor wake to the tail rotor blade is established. Coupled facet / viscous vortex particle method to construct unsteady aerodynamic loads analysis method of tail rotor under helicopter rotor / tail rotor disturbance. The unsteady aerodynamic load characteristics of AH-1G rotor blades are calculated and compared with the experimental measurements and computational fluid dynamics (CFD) calculations to verify the validity of the unsteady aerodynamic perturbation model. Then, based on the NASA ROBIN (Rotor Body Interaction) model, the influence of hovering, crosswind and main rotor with 60 ° right sliding on the unsteady aerodynamic loads of the tail rotor is analyzed. The results show that the main rotor wake has a significant effect on the unsteady aerodynamic loads of the tail rotor. The main rotor / tail rotor interference in the hovering state leads to the decrease of the mean value of the tail rotor pull force and the significant increase of unsteady aerodynamic loads. In the left-hand wind state, the main rotor / tail rotor disturbance weakens the tail rotor “vortex ring” Paddle pull and unsteady aerodynamic loads. At the 60 ° right-slip condition, the main rotor / tail rotor interference causes the maximum loss of the tail rotor, and at the low speed side-slipping state, the tail rotor pull “rapid recovery” phenomenon occurs. The tail rotor is unsteady Aerodynamic load amplitude increases rapidly.