桨叶翼型弯度对摆线桨前飞状态气动性能的影响

Influence of the Bending Degree of the Profile of the Blade on the Aerodynamics of Cycloidal Propeller in Forward Flight

以前飞状态下的摆线桨为研究对象,使用CFD软件进行数值模拟,非定常时间推进采用双时间法,计算模型的刚体运动采用滑移网格技术处理,分别研究了桨叶相对弯度X和最大弯度位置Y对摆线桨气动性能的影响。研究表明：与桨叶为对称翼型的摆线桨相比,当桨叶具有一定的弯度且最大弯度位置适中时,推力和推进效率都有显著提高;随着相对弯度的增加,推进效率先增大后减小,存在一个最佳的相对弯度X使得推进效率最高;随着最大弯度位置向尾缘移动,相对弯度X=2%C时,推进效率缓慢上升,相对弯度X〉2%C时,推进效率先增大后减小,存在一个最佳的最大弯度位置Y使得推进效率最高,但升力和载重系数都有所下降。实际应用时,需综合考虑飞行器实际载重确定合适的桨叶弯度。

With a cycloidal propeller in the forward flight serving as the object of study, a CFD software was employed to conduct a numerical simulation, the dual time method was adopted to implement the unsteady time marching and the sliding grid technology was used to obtain the movement of any rigid body in the calculation model. On this basis, the influence of the relative bending degree X of the propeller and the location Y with a maximal bending degree on the aerodynamic performance were investigated respectively. It has been found that compared with a cycloidal propeller having a symmetrical profile, when the propeller has a certain bending degree and the location with a maximal bending degree is proper, the thrust and propulsion efficiency will all notably go up. With an increase of the relative bending degree, the propulsion efficiency will first increase and then decrease and there will exist an optimum relative bending degree to make the propulsion efficiency arrive at its highest. With the location having a maximal bending degree moves to the trailing edge, when the relative bending degree X = 2% C, the propulsion efficiency will gradually go up and when the relative bending degree X 〉 2% C, the propulsion efficiency will first increase and then decrease and there will exist an optimum location with a maximal bending degree to make the efficiency reach the highest, however, the lift and load factor will all somewhat go down. In the practice, it will be necessary to take account of the real load of an aircraft in a comprehensive way to determine a proper bending degree of its propeller.