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基于一套高效通用的多层运动嵌套网格技术,建立了适合悬停状态倾转旋翼机旋翼/机翼气动干扰特性分析的高效混合计算流体力学(CFD)方法。在倾转旋翼/机翼贴体网格区采用可压雷诺平均Navier-Stokes(RANS)方程作为主控方程,过渡/背景网格区选用Euler方程,湍流模型选用Spalart-Allmaras模型。时间推进上采用双时间推进格式进行非定常求解,并在方法中运用了SPMD(Single Program Multiple Data)模式的并行加速技术。在此基础上,首先分别采用UH-60A直升机旋翼及XV-15倾转旋翼机旋翼作为数值算例,验证了CFD方法的有效性。然后着重对倾转旋翼/机翼的非定常干扰流场及气动力分布特征进行了数值研究,模拟得到与实际情况相符的“喷泉效应”干扰现象。计算结果表明,干扰作用使得倾转旋翼相对于孤立旋翼拉力数值减小了3%,但总的拉力系数损失达到了17%,证明悬停状态下气动干扰对飞行器气动性能有重要影响。
Based on a set of efficient and universal multi-layer kinematic nested grid technology, an efficient hybrid CFD method is developed for the analysis of rotor / wing aerodynamic characteristics of hover rotor. The compressible Reynolds-averaged Navier-Stokes (RANS) equation is used as the governing equation in the rotor / wing patch grid. The Euler equation is selected for the transition / background grid. The Spalart-Allmaras model is used for the turbulent model. The time advancement uses the two-time advance format for unsteady solution, and uses the parallel acceleration technology of SPMD (Single Program Multiple Data) mode in the method. Based on this, the validity of CFD method is verified by using UH-60A helicopter rotors and XV-15 tiltrotor rotor as numerical examples. Then the numerical study on the unsteady disturbance flow fields and aerodynamic characteristics of tilting rotor / airfoil is carried out. The “fountain effect” interference phenomenon is obtained according to the actual situation. The calculation results show that the interference reduces the value of the tilting rotor relative to that of the isolated rotor by 3%, but the total loss of the coefficient of pulling force reaches 17%. It is proved that the aerodynamic interference in the hovering state has an important influence on the aerodynamic performance of the aircraft.