周向布局对高负荷串列叶栅性能的影响

为研不同周向布局下串列叶栅各排性能变化的机理，按扩压因子大小分布设计了一系列串列叶栅，每组串列叶栅进行6种周向布局计算分析；而后对一组串列叶栅前后排叶片积叠轴分别进行了弯曲处理，研究沿展向非均匀周向布局对串列叶栅性能的影响。研究结果表明:周向布局可以改变叶栅通道扩张规律从而改变流场压力分布。随着周向偏距增大，前排负荷增加，后排负荷降低。增大周向偏距可减小串列叶栅前后排损失，T5算例中80%周向偏距方案相对原型损失减少51.3%。前排叶栅决定了串列叶栅可用攻角范围，并且随着周向偏距增大，串列叶栅的可用正攻角增加。随着周向偏距增大，后排叶片端区分离会减小。串列叶栅整体正弯减小14.5%的总压损失系数。采用单独前排反弯或者单独后排正弯分别减小了15.6%和55.2%的总压损失。 

Effects of percent pitch on performance of high load tandem cascade

In order to investigate the mechanism of the forward and aft cascades performance changes at different percent pitches, a series of tandem cascades were designed according to Lieblein factor. The tandem cascades were simulated at six different percent pitches. On this basis, the forward and aft blade stacking lines of a tandem cascade were curved to analyze the influence of the spanwise non-uniform percent pitch on the performance of tandem cascade. The results showed that the expansion of cascade passage and pressure distribution changed with the variation of the percent pitches. The load of forward blade increased while the load of aft blade decreased with the rising percent pitch. Compared with original cascades, the total pressure loss coefficient decreased both at forward and aft blades, the total pressure loss coefficient of T5 blade decreased 51.3% at 80% percent pitch. The incidence angle range of tandem was influenced by forward cascades; the positive incidence angle range increased with rising percent pitch. Corner separation of aft cascades decreased while the percent pitch increased. The total pressure lose coefficient decreased 14.5% when the tandem cascades were positively curved. The total pressure loss coefficient decreased 15.6% and 55.2% when the forward blade was negatively curved or the aft blade was positively curved while the other blade kept straight.