基于CFD的直升机旋翼流场及气动力计算

Computation on Flow Field and Aerodynamic Load of Helicopter Rotors Based on CFD

建立了一个基于结构运动嵌套网格的流场求解器,用来精确模拟复杂的旋翼流场,为更好地预测旋翼气动载荷提供一套计算方法。在该求解器中,控制方程为惯性坐标系下的三维非定常Navier-Stokes方程,空间方向上采用低数值耗散的Roe格式结合三阶逆风格式(Monotonic upwind scheme for conservation law,MUSCL),湍流模式采用了一方程的Spalart-Allmaras模型。应用所建立的方法,分别针对Caradonna模型旋翼、UH-60A直升机旋翼的悬停流场和7A旋翼、SA349/2直升机旋翼的前飞流场以及旋翼气动载荷进行了数值模拟。计算结果表明,本文的方法在一定程度上提高了对旋翼流场的模拟能力,进而提高了旋翼气动载荷的计算精度。

A computational fluid dynamics（CFD） solver based on structured embedded grid is built to simulate the flow field of a rotor and to calculate rotor aerodynamic loads.In this solver,the three-dimensional unsteady N-S equations are employed,and discretized by the combination of the low dissipation Roe scheme and the third-order Monotonic upwind scheme for conservation law（MUSCL）.The Spalart-Allmaras one-equation turbulence model is also adopted.With the developed method,the flow fields and aerodynamic loads of helicopter rotors in hover on Caradonna rotor,UH-60A rotor,and forward flight on 7A rotor and SA349/2 rotor are calculated respectively.It demonstrates that the method is very useful for improving simulation capability on the rotor flow field and thereby increasing the computation precision of rotor aerodynamic loads.