垂直下降状态下的旋翼三维流场数值模拟

Three dimensional numerical simulation of rotor in vertical descent flight

应用激励盘模型,采用计算流体力学(CFD,Computational Fluid Dynamics)方法结合动量叶素理论,计算了旋翼在垂直下降时的流场特征与气动性能.计算过程中,旋翼载荷被描绘成沿桨盘径向分布、与当地流动参数相关的压力源项.在直角坐标系中,运用有限体积方法直接求解了定常不可压N-S(Navier-Stokes)方程,湍流模型为S-A(Spalart-Allmaras)一方程模型,重点使用诱导速度经验公式计算出了压力源项.旋翼流场模拟结果和性能预计结果同实验测量数据吻合较好,表明这种CFD方法可以有效地分析旋翼下降飞行时的空气流动特性,为进一步的涡环状态研究提供了参考.

Using the actuator disc model,blade element momentum theory and computational fluid dynamics（CFD）method,the flow field and aerodynamic performance of a helicopter rotor in vertical descent flight were simulated.In calculation,the loads of spinning rotor were represented as momentum source terms distributed along the span of the rotor with functional relationship to the local flow conditions.The finite volume method was adopted and incompressible Navier-Stokes（N-S） equation was solved in Cartesian coordinates.The Spalart-Allmaras（S-A） turbulence model,especially the induced velocity empirical formulae were also included in the calculation method.The simulation results for flow field and aerodynamic performance show good agreement with the experiment data.Therefore,this numerical simulation technique is proved to be feasible for analyzing rotor flow characters in descent condition and it also provides the references for the further vortex ring state research.