对转开式转子非定常气动干扰特性分析

采用动态面搭接技术,求解非定常雷诺平均Navier-Stokes方程实现对转开式转子的非定常气动数值模拟.对10片桨叶单个转子和10×10对转开式转子构型分别进行模拟,对比分析前后两个转子间的气动干扰和滑流流动干扰.结果表明:与单个转子相比,对转开式转子前转子的拉力系数和功率系数减小,后转子的拉力系数和功率系数则都增大,并在一个旋转周期内都呈现20次周期性波动.前后转子拉力系数的频谱分析显示振荡发生在桨叶通过频率的偶数倍,且在2倍时后转子拉力的振幅最大.前转子桨尖涡与后转子的周期性干扰,引起后转子桨叶力分布的变化和非定常性.与单个转子相比,前转子后滑流轴向速度偏大,周向速度偏小.后转子对滑流有二次加速及旋涡恢复作用.

Characteristic analysis of unsteady aerodynamic interactions of contra rotating open rotor

Unsteady aerodynamics of contra rotating open rotor (CROR) was simulated by solving unsteady Reynolds averaged Navier-Stokes equations based on dynamic patched technology. To analyze the aerodynamic interactions and slipstream flows interactions between the front-rotor and aft-rotor, a 10×10 CROR configuration was adopted and compared with the 10-bladed single rotor. Result shows that,compared with the single rotor, the thrust coefficients and power coefficients of the front-rotor decrease while those of the aft-rotor increase, with 20 periodical oscillations during one rotation period. The spectral analysis of front-rotor and aft-rotor thrust coefficients show that the fluctuations occur at even multiple numbers of blade passing frequency of single rotor, and the amplitude of aft-rotor thrust at twice the blade passing frequency is prominent. Due to the periodical passing of blade tip vortices of front-rotor, the thrust distributions on aft-rotor blade are changed and fluctuate unsteadily. Compared with the single rotor, the axial velocity increases while the cirumferential velocity decreases in the slipstream behind front-rotor. The aft-rotor accelerates the slipstream while recovers swirls.