自适应襟翼流动控制改进方法的提出与验证

Proposal and Validation of Improving Methods for Flow Control Performance of the Adaptive Flap

减缓叶片流动分离已成为当前提高叶轮设备运行效率与安全性的主要措施。自适应襟翼仿生自鸟类翅膀上的羽毛,其在翅膀出现流动分离时受回流冲击向上抬起,进而阻止流动分离的发展。基于数值模拟所得到的襟翼表面压力分布规律,提出了合成力矩控制方法用以改进襟翼流动控制效果,并结合已有的线性力矩控制方法,验证了上述2种方法在不同流动分离过程中提升襟翼作用效果的有效性。结果表明:2种改进方法均能够有效提升襟翼的流动控制效果,其中合成力矩方法整体表现较好,且能够避免自由运动襟翼在流动分离较小时的过度抬起;此外,自适应襟翼在大攻角时还通过延后分离涡的生成与脱落,减弱了分离涡的影响,从而使升阻力系数波动幅度降低。

Slowing down the blade flow separation has become a main measure to improve the efficiency and safety of impeller equipment. The adaptive flap inspired by the feathers on the bird’s wing, which are lifted upward by the backwash when flow separation occurs on the wing, thereby preventing the development of separated flow. Based on the rules of pressure distribution on the flap surface obtained from numerical simulation, a synthetic torque control method was proposed to improve the flap flow control performance. Combined with the existing linear torque control method, the effectiveness of the above two methods in improving the flap performance in different flow separation processes was verified. The results show that the two improved methods both effectively improve the flap flow control performance. The synthetic torque method has a better overall performance and can avoid the over-lift of the free-moving flap occurring in the relatively weak flow separation. In addition, the adaptive flap can also reduce the intensity of separation vortices by delaying the generation and shedding of separated vortices at large angle of attack, thus reducing the fluctuation amplitude of the lift coefficient and drag coefficient.