中文摘要：

利用数值模拟对涵道共轴双旋翼的空气动力学特性进行研究。探讨在涵道的影响下,双旋翼距离的变化对上下旋翼拉力和扭矩的影响。通过与共轴双旋翼的对比确定涵道共轴双旋翼产生拉力的机理并分析涵道本体对共轴双旋翼气动特性的影响。数值结果表明：随着旋翼间距的增大,开始时上旋翼拉力大于下旋翼拉力,后来发生逆转。最后计算了上旋翼拉力占总拉力比值的变化关系。

英文摘要：

The aerodynamic characteristics of ducted coaxial rotor were analyzed based on the numerical simulation method.The influence of ducted body on aerodynamic characteristics of the ducted coaxial rotor was discussed and also the influence of coaxial rotor spacing was investigated on lift and torque acquired by rotors above and below.The mechanism of lift produced by the ducted isolated coaxial rotor was determined by comparison of difference between ducted coaxial rotor and coaxial rotor.Numerical results show that the lift of rotor above is greater than that of rotor below at first,but then it becomes reverse as the rotor spacing is growing.The curves of ratio of lift attained by the rotor above to total tension are finally established.