轴向超声速通流串列构型弦长比对气动性能影响的数值研究

Numerical Study on Effects of Chord Length Ratio of Axial Supersonic Through-Flow Tandem Configuration on Aerodynamic Performance

关键词:  轴向超声速通流风扇  串列叶片  弦长比  激波  尾迹损失  气动性能

Key words:  Axial supersonic through-flow fan  Tandem blade  Chord length ratio  Shock  Wake loss  Aerodynamic performance

摘要:

为避免高马赫数、大攻角来流引发的叶片颤振，将串列叶片技术引入到超声速通流风扇叶栅中，对其进行串列改型及气动性能研究。利用准二维数值模拟，对串列叶片前、后排叶片的弦长比参数进行了详细的对比研究。结果表明：影响气动性能的关键因素是后排叶片进口压力侧激波的落点，在本文研究条件下，随着弦长比的减小总压损失呈减小的趋势，当弦长比由0.99减小到0.43时，设计攻角下，15°折转角叶型总压损失可减小27%，30°折转角叶型总压损失可减小38%。进一步的研究表明，通过减小弦长比可有效控制后排叶片前缘斜激波在相邻叶片吸力侧的落点以实现损失降低，并且这种降低效应在小弯角叶型上比大弯角叶型更容易实现。

Abstract:

To avoid blade flutter caused by the incoming flow with a high Mach number and a large incidence angle， the tandem blade technology is introduced into the Supersonic Through-Flow Fan （STFF） cascade， and the preliminary two-dimensional tandem modification and aerodynamic performance are studied. A detailed comparative study on the effect of chord length ratio for the front and rear blades of tandem blades is conducted through numerical simulation. The results show that the key factor affecting the aerodynamic performance is the impingement point of the leading edge shock on the pressure side of the rear blade. Under the conditions of this study， total pressure loss drops with decreasing in the chord length ratio. When the chord length ratio decreases from 0.99 to 0.43， the total pressure loss with a camber angle of 15° is reduced by 27% at design incidence while one with a camber angle of 30° is reduced by 38%. Further study shows that it is effective to reduce the loss by reducing the chord length ratio to control the rear blade leading-edge shock impingement location on the suction side and it is easier to achieve a reduction in the loss for a tandem blade with a small camber angle than that with a large camber angle.