变距四旋翼飞行器气动力及噪声特性计算研究

Computational Research on Aerodynamic and Noise Characteristics of Variable Pitch Quadrotor Aircraft

基于计算流体力学(CFD)建立了适用于多旋翼飞行器的流场计算模型,采用嵌套网格方法模拟旋翼运动、双时间方法进行时间推进,分析变距四旋翼飞行器的气动力特性。在此基础上,采用FW-H(Ffowcs Williams-Hawkings)方程计算了变距四旋翼飞行器的噪声特性(包括考虑和不考虑旋翼间气动干扰两种情况)。计算结果表明,由于旋翼间的气动干扰,致使变距四旋翼的载荷噪声较大,进而导致总噪声较大。在对变距四旋翼飞行器噪声进行仿真时,考虑旋翼间气动干扰是必要的。

In order to analyze the aerodynamic force characteristics of the multi-rotor aircraft,a flow field calculation modal is established based on the computational fluid dynamics(CFD).The nested grid method is used to simulate the blade motion,and the dual-time method is used for time propulsion.Based on this,the noise characteristics of the multi-rotor aircraft are calculated by using FW-H equation.A variable pitch quadcopter is selected for the study which considers and does not consider the aerodynamic interference between the rotors,and the aerodynamic and noise characteristics are compared and analyzed.The calculation results show that the amplitude of aerodynamic pulsation amplitude of the quadrotor is larger due to aerodynamic interference between rotors.The intensity characteristics of the quadrotor will be overestimated if the aerodynamic interference between rotors is not considered.The load noise of the quadrotor plays a dominant role in the total noise,whether it is hovering of flying flat.Because of the aerodynamic interference between the rotors,the load noise of the quadrotor aircraft is larger,which leads to the larger total noise.It is necessary to consider aerodynamic interference between rotors when simulating the noise of quadrotor aircraft.