基于GKS理论与笛卡尔网格的旋翼流场数值研究

Numerical Simulation of Rotor Flowfield Based on GKS Theory and Cartesian Grid

摘要: 直升机的旋翼气动力模型之所以比固定翼的复杂，体现在其许多参数都是非定常的，如直升机的旋翼升力和相对气流的速度大小、方向以及桨叶的切面迎角密切相关，即使直升机在定常飞行状态下，这些因素也是随时间发生变化的。现有的欧拉方程法在模拟运动的旋翼运动时，受到网格及其变形等的诸多限制，并不能精确地模拟旋翼的实时运动，因此，本文依据Boltzmann方程，运用GKS理论，采用笛卡尔自适应网格技术来实现翼型位置的实时变化，对NASA12翼型进行运动分析，最终获得旋翼的模拟结果。通过分析模拟结果，即翼型的宏观特性，翼型的升力以及旋涡等的分布，并将数值模拟结果和经典的试验结果进行对比。对比结果表明，整体模拟结果和Caradonna-Tung试验结果误差很小，因此，本文的方法能够较为精确地模拟直升机翼型的运动。

Abstract: The reason why the rotor aerodynamic model of helicopter is more complex than that of fixed wing is that many of its parameters are unsteady. For example, the rotor lift of helicopter is closely related to the velocity and direction of the relative air flow and the section angle of attack of blade. Even if the helicopter is steady, these factors change with time. When the existing Euler equations simulate the moving rotor motion, it receives many restrictions such as grid and its deformation, and cannot accurately simulate the motion of the rotor in time. Therefore, based on Boltzmann equation, GKS theory and Cartesian adaptive grid technology, this paper realizes the real-time change of airfoil position and analyzes the motion of the wing nasa12. Finally, the simulation results of rotor are obtained. The numerical simulation results are compared with the classical test results, such as the characteristics of the airfoil, the lift of the airfoil and the distribution of vortices. The comparison results show that the errors between the overall simulation results and caradonna Tung test results are few. Therefore, the method in this paper can accurately simulate the motion of helicopter airfoil.