基于隐式算法的悬停旋翼粘性绕流高效CFD分析方法  

Highly-efficient CFD calculations on viscous flow of hovering rotor based on the implicit algorithm

作　　者：吴琪[1] 招启军[1] 赵国庆[1] 王博[1] 

机构地区：[1]南京航空航天大学直升机旋翼动力学国家级重点试验室,江苏南京210016

出　　处：《空气动力学学报》2015年第4期454-463,共10页Acta Aerodynamica Sinica

基　　金：国家自然科学基金(11272150)

摘　　要：为显著提高旋翼粘性绕流CFD模拟效率,建立了一套高效的基于隐式LU-SGS算法和OpenMP并行策略的旋翼悬停流场求解方法。首先,求解Poisson方程生成桨叶剖面翼型的贴体正交网格,并通过剖面网格插值、翻折方法生成桨叶C-O型贴体网格;在此基础上,采用基于"扰动衍射"挖洞方法与"Inverse map"相结合的洞边界划定与贡献单元搜索方法,解决了嵌套网格技术中的相关瓶颈问题。然后,以非惯性系下耦合S-A湍流模型的RANS方程为流场主控方程,对流通量采用三阶Roe-MUSCL格式进行离散,时间推进采用高效的隐式LU-SGS方法,同时采用基于数据共享的OpenMP并行策略加速流场求解。最后,运用所建立的方法分别对不同旋翼翼型和悬停状态"Caradonna-Tung"以及UH-60A旋翼的流场及气动特性进行了计算,并给出了根据涡核位置加密网格来提高桨尖涡捕捉精度的方法,同时将计算结果与试验值进行了对比,验证了该方法在旋翼CFD流场模拟中的高效性和高精度特征。To improve the CFD compute efficiency on the viscous flow of helicopter rotor, a highly-efficient implicit LU-SGS algorithm and OpenMP parallel strategy have been employed for predicting the aerodynamic characteristics of hovering rotor. Firstly, the orthogonal and body- fitted grid around rotor blade is generated by using Poisson equations and folding approach; then the ＂disturbance diffraction method＂（DDM） and ＂Inverse map＂ method are utilized in the identi- fication of hole cells and searching the donor cells respectively, thus to solve the bottleneck prob- lem of the embedded grid technique. On these bases, the RANS equations coupled S-A turbu- lence model in a rotating frame are used as the governing equations, and the three-order scheme of ROE-MUSCL is used for spatial discretization of convective fluxes, and the highly-efficient implicit scheme of LU-SGS is adopted for temporal discretization, and data sharing OpenMP parallel strategy is employed to accelerate the calculation as well. Finally, the flowfield and aerodynam- ic characteristics of several rotor airfoils and hovering rotors（C-T and UH-60A rotor） have been simulated by the presented method. At the same time, a refined grid strategy according to the position of vortex core has been conducted to improve the capturing accuracy of blade-tip vortex.By comparisons of numerical results with experiment data, high-efficiency and high-accuracy abil- ities of the present method on the simulation of the rotor flowfield is demonstrated.

关 键 词：旋翼 气动特性 RANS方程 隐式算法 Spalart-Allamaras湍流模型 嵌套网格方法 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]