通过旋翼台试验和数值模拟方法对具有China Laboratory of Rotorcraft(CLOR)桨尖旋翼的悬停气动性能进行研究。为进行对比研究,共设计完成3副模型旋翼,分别为参考的矩形桨叶、常后掠桨尖的桨叶以及具有CLOR桨尖气动外形的桨叶。在模型旋翼台上进行这3副模型旋翼在不同转速、不同桨叶安装角条件下的旋翼拉力和扭矩测量;数值计算是采用一个基于Narier-Stokes方程/自由尾迹分析/全位势方程的旋翼流场求解的混合计算流体力学(CFD)方法进行的,计算结果与试验结果显示出较好的一致性。在此基础上,数值模拟了在旋翼试验台上很难开展的高速旋转试验状态。最后,根据试验和数值结果,对比分析具有CLOR新型桨尖旋翼与矩形桨尖以及常后掠桨尖旋翼的悬停气动性能,得出关于非常规气动外形桨尖对旋翼气动特性的影响机理,初步体现了CLOR桨尖旋翼具有良好的悬停性能。
A robust unsteady rotor flowfield solver CLORNS code is established to predict the complex unsteady aerodynamic characteristics of rotor flowfield. In order to handle the difficult problem about grid generation around rotor with complex aerodynamic shape in this CFD code,a parameterized grid generated method is established, and the moving-embedded grids are constructed by several proposed universal methods. In this work, the unsteady Reynolds-Averaged Navier-Stokes(RANS) equations with Spalart-Allmaras are selected as the governing equations to predict the unsteady flowfield of helicopter rotor. The discretization of convective fluxes is accomplished by employing the second-order central difference scheme, third-order MUSCL-Roe scheme, and fifth-order WENO-Roe scheme. Aimed at simulating the unsteady aerodynamic characteristics of helicopter rotor, the dual-time scheme with implicit LU-SGS scheme is employed to accomplish the temporal discretization. In order to improve the computational efficiency of holecells and donor elements searching of the moving-embedded grid technology, the ‘‘disturbance diffraction method" and ‘‘minimum distance scheme of donor elements method" are established in this work. To improve the computational efficiency, Message Passing Interface(MPI) parallel method based on subdivision of grid, local preconditioning method and Full Approximation Storage(FAS) multi-grid method are combined in this code. By comparison of the numerical results simulated by CLORNS code with test data, it is illustrated that the present code could simulate the aerodynamic loads and aerodynamic noise characteristics of helicopter rotor accurately.
