摘要
针对直升机旋翼非定常气动特性CFD模拟中的网格生成难题,提出了一套高效、通用的运动嵌套网格生成方法.首先,基于Poisson方程求解和翻折法生成旋翼桨叶的正交贴体网格.其次,针对旋翼桨叶的扭转分布及变距、挥舞等复杂运动,建立了一套通用的洞单元识别的扰动衍射法;为保证洞包络面的封闭性,完善了挖洞过程中网格加密策略;在洞边界确立基础上,提出了一种高效、鲁棒的最小距离法贡献单元搜索的改进方法.在此基础上,建立了基于RANS(Reynolds-averaged Navier-Stokes)方程的旋翼非定常流场CFD模拟方法.最后,采用所建立的方法分别对悬停和前飞状态下的C-T(Caradonna-Tung)旋翼和7A(Helishape 7A)旋翼的气动特性、桨尖涡的位置进行了计算,计算结果与试验值误差小于5%,验证了该运动嵌套网格生成方法在旋翼非定常气动特性CFD模拟中的有效性.
Targeting the problem on grid generation for the CFD simulation of the un- steady aerodynamic characteristics of helicopter rotor, a highly-efficient and universal mov- ing-embedded grid generation method was proposed. Firstly, the orthogonal and body-fitted grid around rotor blade were generated by using Poisson equations and folding approach. Then, considering the twist distribution and the complex pitching, flagging motion of rotor blade, a method for the identification of hole cells named disturbance diffraction method was established. In order to ensure the closeness of hole envelope surface, the grid refinement strategy in the hole-cutting procedure was improved. Meanwhile, based upon the determina- tion of the hole boundary, an modified minimum distance scheme of donor element method with high efficiency and robustness was developed for searching the donor cells. On these ba- sis, the CFD simulation method for unsteady flowfield of rotor was conducted by solving the RANS （Reynolds-averaged Navier-Stokes） equations. Finally, the aerodynamic characteris- tics and location of the blade tip vortex for C-T （Caradonna-Tung） and 7A （Helishape 7A） rotors were simulated by the presented method in hovering and forward flight respectively.The errors of numerical results are less than 5% according to the experiment data, and the effectiveness of CFD simulation on the unsteady aerodynamic characteristics of different rotors is demonstrated.
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2015年第3期546-554,共9页
Journal of Aerospace Power
基金
国家自然科学基金(11272150)
江苏高校优势学科建设工程
关键词
旋翼
非定常气动特性
运动嵌套网格
扰动衍射法
最小距离法
rotor
unsteady aerodynamic characteristics
moving-embedded griddisturbance diffraction method
minimum distance scheme of donor element
