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为研究悬停状态下旋翼的间距对微型共轴双旋翼气动性能的影响,文中通过搭建试验平台对间距比h/r分别为0.32、0.38、0.45、0.51、0.58、0.65和0.75下的共轴双旋翼进行气动性能测试,以测量不同旋翼转速下所得共轴双旋翼的拉力和功耗对共轴双旋翼气动布局进行优化,试图找出具有最佳气动特性的共轴旋翼布局。另外,通过试验误差分析确定了相应的拉力系数、功率系数和功率载荷,且试验误差均小于2%。同时,为更直观得到不同间距下气流干扰对旋翼系统气动性能的影响,文中采用数值模拟得到了不同间距比下旋翼的流线分布和压力分布。最后,对比试验结果,综合分析旋翼间气动干扰的影响,最终得到间距比h/r为0.38时的共轴双旋翼具有最佳的气动布局。研究结果表明,悬停状态的共轴双旋翼可以通过改变间距大大提高气动性能,且同一间距下转速越大虽然旋翼间干扰越强烈,但此时开始出现耦合,使得系统的气动性能可能更好,同时,由于上下旋翼间的相互诱导,虽然转速较低时升力较小,但是功耗明显低于高转速,使得系统具有更大的功率载荷。
In order to study the effect of rotor pitch on the aerodynamic performance of micro coaxial co-rotor under hovering conditions, a set of test platform was used to test the aerodynamic performance of the coaxial co-rotor with a ratio h / r of 0.32,0.38,0.45,0.51,0.58,0.65 and 0.75 The aerodynamic performance of the twin rotors was tested to optimize the aerodynamic layout of the coaxial twin rotors by measuring the pull and power dissipation of the coaxial twin rotors at different rotor speeds in an attempt to find the co-axial rotor configuration with the best aerodynamic characteristics. In addition, the corresponding tensile coefficient, power coefficient and power load were determined by experimental error analysis, and the experimental errors were less than 2%. At the same time, in order to more intuitively obtain the influence of the airflow disturbance on the aerodynamic performance of the rotor system under different pitches, the flow distribution and pressure distribution of the rotor under different pitches are obtained by numerical simulation. Finally, the experimental results are compared and the aerodynamic interference between the rotors is analyzed. Finally, the optimal aerodynamic configuration of the coaxial twin rotors with the h / r ratio of 0.38 is obtained. The results show that the co-rotating twin rotor can greatly improve the aerodynamic performance by changing the pitch, and the greater the rotation speed under the same pitch, the stronger the interference between the rotor blades, but at this time, the coupling begins to make the aerodynamic performance of the system better At the same time, due to the mutual induction between the upper and lower rotors, the power is obviously lower than the high speed, which makes the system have a greater power load, although the lift is lower when the speed is lower.