非对称尾迹对低压涡轮叶片附面层影响的研究

Effects of Asymmetry Wakes on Boundary Layer of Low Pressure Turbine Blade

关键词:  LPT叶片  附面层  分离  尾迹

Key words:  Low pressure turbine airfoil  Boundary layer  Separation  Wakes

摘要:

针对低雷诺数下低压涡轮(LPT)叶片尾迹存在的不对称性，研究了一种在近场与LPT尾迹更加接近的非对称尾迹对下游叶片附面层的影响，以求在不增加实验难度或计算量的前提下，提高研究过程中尾迹对下游叶片流动影响预测的精确性。研究以CFX软件为工具，以Packb高负荷LPT叶型为研究对象，分析了圆棒、三角形尾迹与叶片近场尾迹的相似性，对比了在圆棒与三角形尾迹扫掠下，叶片吸力面附面层的流动特性。研究发现，与圆棒尾迹相比，偏置的三角形尾迹与低雷诺数下的LPT叶片尾迹更加相似，且可更好地抑制吸力面分离。

Abstract:

Considering the asymmetry of the wake of the low pressure turbine blade (LPT) at low Reynolds number，the effects of the asymmetric wakes which is similar to LPT wakes on the boundary layer of downstream blade rows in the near field has been conducted. It is expected to have no increment to the difficulty of experiment or the load of calculation as the premise while improving the prediction accuracy of the wake flow to the downstream blade. Packb high-lift LPT airfoil is studied by CFX software. After analyzing the similarity of the wake generated by the cylindrical bar，the triangular wedge and the wake of LPT blade in the near-field，the flow characteristics of the boundary layer on the suction surface under the different wakes has been compared. In this research，it has been found that the triangular wedge with deflection shares more similarities with the wake of LPT blade airfoil at low Reynolds number，and the separation on suction surface is also suppressed effectively.