论文部分内容阅读
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.
Aiming at the problem of grid generation in unsteady aerodynamic characteristics CFD simulation of helicopter rotors, a set of efficient and universal motion nested grid generation method is proposed.Firstly, based on the Poisson equation solving and turning method, Body grid.Secondly, a set of general perturbation diffraction method for hole element identification is established in view of the torsional distribution of rotor blades and the complicated movement such as pitch variation and waving. In order to ensure the closure of the cave envelop, the tunneling is improved Based on the establishment of the hole boundary, an efficient and robust method of minimum-distance contribution cell search based on RANS (Reynolds-averaged Navier-Stokes) is proposed. Equation CFD simulation method of rotor unsteady flow field.Finally, the aerodynamic characteristics of the Caradonna-Tung (CT) rotor and the 7A (Helishape 7A) rotor in the hovering and pre-flying state, The results show that the error between the calculated result and the experimental value is less than 5%, which verifies the effectiveness of the method for generating the motion nested grid in CFD simulation of rotor unsteady aerodynamic performance.