共轴双旋翼自转气动特性

为了研究共轴双旋翼自转状态下的气动特性,开展了共轴双旋翼自转气动特性理论和试验研究.采用叶素理论计算旋翼力及力矩特性,引入气动干扰模型及动态入流捕捉旋翼流场的变化,对共轴双旋翼自转状态下的气动特性进行了理论分析和计算.风洞吹风试验与理论模型计算对比分析表明:旋翼转速较大时的误差小于5%,验证了理论模型的有效性.获得了上/下旋翼转速及升力随着总距角、后倒角、上/下旋翼间距及风速的变化关系.对比分析了上/下旋翼的相互气动干扰强度,获得了有效的共轴双旋翼自转时旋翼拉力分配的计算方法. 

Research on aerodynamic characteristics of autorotating coaxial twin-rotor

In order to investigate the aerodynamic characteristics of autorotating coaxial twin-rotor,the wind-tunnel test of an autorotating coaxial twin-rotor was performed with the theorical investigation.The blade element theory is adopted to calculate aerodynamic force and moment.The aerodynamic interaction model and the dynamic inflow model were used to investigate the inflow of the autorotating coaxial twin-rotor.The comparison between experiment and calculation shows that the error is less than 5% when the rotor speed is greater than 300r/min.Thus,the model of the aerodynamic characteristics of autorotating coaxial twin-rotor was verified.The relationship of speed and lift of the twin-rotor and the design parameters which included pitch angle,shaft angle,the distance between the upper rotor and the lower rotor,and wind speed of the wind tunnel was obtained.The aerodynamic interaction between the rotors was analyzed.The method of calculation for the thrust ratio of the upper rotor and the lower rotor was derived.