应用时间精确自由尾迹方法的桨叶总距突增响应特性分析

Calculation of Rotor Responses with Abrupt Increase of Collective Pitch Based on Time-Accurate Free-Wake Method

摘要:

直升机旋翼的气动特性对总距操纵输入的动态响应具有复杂的非定常特性。文中结合尾迹模型、PC2B算法、桨叶气动模型、挥舞动力学模型、非定常翼型模型和旋翼平衡模型,建立了一个时间精确旋翼自由尾迹和气动特性分析方法。利用该方法,首先,计算了前飞时旋翼入流分布,以及悬停状态桨叶总距增加时拉力系数的变化,通过计算值与实验值的对比,验证了方法的有效性；然后,利用该方法对模型旋翼在悬停和前飞状态桨叶总距阶跃突增时的拉力系数、俯仰力矩系数、滚转力矩系数和挥舞锥度角变化的时间历程进行了计算分析,得出了一些新的结论。

Abstract:

Aerodynamic characteristics and responses of rotor with control inputs present complex unsteadiness. A time-accurate free-wake calculation method was developed based upon wake model, PC2B algorithm, blade model, unsteady airfoil model and trim model. Using the developed method, the calculations on rotor inflow for forward flight and thrust coefficient with ramp increase in rotor collective pitch angle for hover were firstly carried out. By comparisons between the calculated results and available experimental data, the capability of the present method was demonstrated. Then, the rotor thrust coefficient, moment coefficient and blade flapping responses with the abrupt increase of collective pitch angle were calculated and analyzed, and some meaningful results were obtained.