悬停状态倾转旋翼机非定常气动干扰研究

悬停状态旋翼/机翼机身干扰流场的高精度数值模拟对准确预估倾转旋翼飞行器气动性能具有十分重要的意义，开展该干扰流场的高精度数值模拟一直是直升机空气动力学领域的研究热点和难点之一。本文基于运动嵌套网格技术，建立一套适用于倾转旋翼非定常流场的CFD方法。采用雷诺平均Navier-Stokes(RANS)方程作为主控方程，湍流模型选用Spalart-Allmaras模型，时间推进上采用高效的隐式LU-SGS格式。在此基础上，首先开展某新型倾转旋翼无人机的旋翼/机翼机身非定常干扰流场数值模拟研究，得到了与文献相符的“喷泉效应”现象，计算结果显示干扰作用使总拉力损失16.6%。然后着重研究了不同襟副翼预置角对降低悬停状态下旋翼/机翼机身气动干扰作用的影响，研究结果显示45°襟副翼预置角效果最佳，使全机总拉力损失从原来的16.6%降到13.8%。

Researches on Unsteady Aerodynamic Interference of the Tiltrotor Aircraft in Hover

The high resolution numerical simulation of rotor/wingbody interaction flowfield in hover is crucial for the accurate prediction of aerodynamic performance of the tiltrotor aircraft. The study of interaction flowfield high resolution numerical simulation is the important issues of helicopter aerodynamics. Based on the moving-embedded grid technique, a CFD simulation method for predicting unsteady flowfield is established. Reynolds-averaged Navier-Stokes(RANS) equations are used as governing equations and Spalart-Allmaras turbulence model is employed, implicit LU-SGS scheme is adopted. On this basis, the unsteady interaction flowfield of the rotor/wingbody are investigated in deep research, and the special phenomenon ''fountain effect'' is simulated, the results indicate that the total thrust loss is about 16.6% as compared to the isolated rotor. Furthermore, it studies the different preset flaps/ailerons affect on decreasing rotor/wingbody aerodynamic interference. The results show that the lowest aerodynamic interference presents the preset flaps/ailerons angle 45 degree. In the preset angle of 45 degree, the total thrust loss reduces to 13.8% from 16.6%.