主/从动式组合旋翼悬停状态气动特性分析

针对传统直升机构型中主旋翼旋转时产生的扭矩需要尾翼或是反向旋转的共轴旋翼加以抵消,从而造成能量浪费的问题,以将主旋翼旋转时产生的扭矩转化为升力为出发点,提出了一种主旋翼带动下方无动力旋翼旋转的主/从动式组合旋翼气动布局构型。通过动量叶素理论以及CFD数值模拟中的多重参考系法,对主/从动式组合旋翼悬停状态的气动特性进行了初步分析,结果表明,此构型中的下方从动旋翼利用上方主动旋翼的扭矩产生了额外10%的升力,同时下方从动旋翼在上方主动旋翼引流的有利干扰下升力系数提高了35%。

Analysis of Aerodynamic Characteristics of Combined Rotors in Hover

The torque-moment generated by main rotor of helicopter is usually offset by counter torque -moment produced by tail rotor or coaxial rotor which leads to the waste of energy .In order to solve this problem,a new conception of combined rotors whose un-powered lower rotor is driven by the torque-mo-ment produced by upper active rotor was proposed , basing on the idea of converting torque-moment to lift.The methods of the blade element momentum theory （ BEMT ） and multiple reference frame method （MRF） of CFD technique were used to analyze the aerodynamic characteristics of combined rotors in hover.The results shows that the combined rotors manage to transform the torque -moment to additional lift which accounts for 10%of the original lift .And the lift coefficient of un-powered lower rotor increases by 35%because of the advantageous interference of the upper active rotor .