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针对倾转旋翼特有的悬停、巡航、过渡3种飞行模式,基于CFD方法分别对倾转旋翼的上述3种典型飞行状态进行了数值模拟.首先,基于运动嵌套网格思想建立了适合倾转旋翼运动模拟的多层运动嵌套网格系统.然后,基于RANS(Reynolds averaged Navier-Stokes)方程建立了适用于非定常流场分析的CFD模拟方法.为了提高整个流场的计算效率,时间推进采用高效的隐式LU-SGS(lower upper symmetric Gauss Seidel)方法,并运用SPMD(single program multiple data)并行计算模式.最后,采用所建立的网格生成方法和流场求解器,进行了不同飞行状态下的倾转旋翼气动特性数值分析,验证了建立CFD方法的有效性并得出了多种飞行状态下的气动特性.结果表明:悬停状态下倾转旋翼相对于直升机旋翼有更加明显的下洗流影响区域.巡航状态两旋翼中心间距为2.5R时,倾转旋翼之间存在明显的气动干扰.过渡状态下,倾转旋翼提供的拉力在倾转角为45°前下降较快,且在倾转角较小时,倾转旋翼桨叶表面拉力分布仍能表现出直升机旋翼的特性.
Three kinds of flight modes of hovering, cruising and transition of tilting rotor are simulated and the three typical flight states of tilting rotor are numerically simulated based on CFD method.Firstly, based on the idea of nested grid, Rotor motion simulation of multi-layer motion nested grid system.Then, based on the Reynolds averaged Navier-Stokes (RANS) equation, a CFD simulation method suitable for unsteady flow field analysis is established.In order to improve the computational efficiency of the entire flow field, time Adopting highly efficient implicit LU-SGS (parallel upper-centered symmetric Gauss Seidel) method and SPMD (single program multiple data) parallel computing mode.Finally, using the established grid generation method and flow field solver, The numerical analysis of the aerodynamic characteristics of the tilting rotor under flight conditions validates the effectiveness of the CFD method and obtains the aerodynamic characteristics under various flight conditions.The results show that the tilting rotor is more obvious than the helicopter rotor under hovering condition Of the wash flow affected area. Cruising state of the two rotor center spacing of 2.5R, there is significant aerodynamic interference tilting rotor transition state, tilting When the tension flap is provided in the tilt angle 45 ° before decreased rapidly, and the tilt angle is small, the tilting of the rotor blade surface tension distributing still exhibits the characteristics of a helicopter rotor.