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针对45°叶型转折角扩压叶栅及增加小叶片后组成的大小叶片叶栅,分别测量了其在设计工况及不同气流攻角下的叶栅气动性能,通过PIV实验获得了对应工况下的叶栅内部流动状态.结果表明:增加小叶片后,叶片压力面至吸力面的压力梯度明显降低,大叶片载荷降低;在设计工况下,叶栅气流落后角仍可参考霍威尔半经验公式进行计算,但偏离设计工况后,该公式存在较大误差;大小叶片叶栅的气流落后角仅在小气流攻角下明显减小,在其余工况下变化不大;不同气流攻角下小叶片对大叶片表面气流流动分离起到约束作用;在设计工况至大气流攻角工况变化过程中,叶栅扩压损失有所降低.
The aerodynamic performance of cascades at 45 ° airfoil with different angles of inflow and at different angles of attack was measured respectively for the cascades of 45 ° airfoil turning angle and the blade cascades with small blades. After the PIV experiment, The result shows that the pressure gradient from the pressure surface to the suction surface of the blade decreases obviously and the load of the large blade decreases when the small blade is added.At the design condition, However, the deviation of the formula from the design condition leads to a large error. The backward angle of the airflow in the blade cascade decreases obviously only under the small angle of attack, and does not change much under the other conditions. Airfoil at the angle of attack of air flow restricts airflow separation on the surface of large blades. During the changing of design conditions to the conditions of air-flow angle of attack, the diffuser loss of cascade decreases.