共轴式直升机双旋翼载荷计算模型研究

理论计算和实验测量表明,共轴式直升机在悬停、前飞状态下,上下旋翼桨盘处轴向诱导速度分布与单旋翼直升机的相类似,本文根据共轴式直升机双旋翼这一特点,引入气动力相互干扰因子,将单旋翼直升机一阶谐波形式的Pitt-Peters静态非均匀入流模型推广到共轴式直升机,建立了一种共轴双旋翼载荷计算模型,为共轴式直升机飞行动力学建模作前期准备。以某共轴双旋翼为研究对象进行载荷计算,并与国外计算结果进行了对比,两者吻合较好。 

Mathematical Model for Twin Rotor Loads of a Coaxial Helicopter

The results of theoretical analysis and experiment have validated that the axially induced velocity distribution at the upper and lower discs of the coaxial twin rotor system is similar to that of the single rotor in hovering and forward flights. In this paper,by introducing an interaction factor and extending the first harmonic nonuniform inflow Pitt-Peters model for the single rotor helicopter to the coaxial helicopter, a simplified and practical mathematical model for coaxial twin rotor loads is formulated. This model avoids the complicated analysis and numerical calculations of the vortex models or CFD methods for obtaining the axially induced velocity at the upper and lower discs. Moreover, it can be employed for coaxial helicopter flight dynamics numeral simulation. The forces and moments on the sample coaxial twin rotor hub are calculated with the help of the math model. The computational results are in good coincidence with those from Russian model.