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.