The differences of flow field in bowed blade cascade and that in straight blade cascade are systematically studied in this paper. To bow a blade means to change its geometric boundary condition. This change not only affect the pressure distribution along the blade profile exit Mach number but also has great effect on the original position and development of the passage vertex. All of the changes mentioned above have great influence on the loss.
Numerical simulation result showed that blade bowing can decrease the cross-pressure gradient near the end wall. This trend will be more obvious with the increase of the bow angle. The pressure gradient decrease is beneficial to weaken the passage vortex strength and reduces the secondary loss near the endwalls. In addition, Pressure gradient from endwalls to midspan can be established near suction surface in positively bowed blade. With the increase of bow angle, this C-type pressure distribution is remarkable. It is also found that this C-type pressure distribution will influence the position of corner vortex near the suction surface and will also influence the position and size of the passage vortex. Blade bowing also has great influence on the position of the saddle point near the leading edge and the separated line of the horseshoe vortex. It is found that the position of the saddle point and the separated line of both legs of the horseshoe vortex move forward in a positively bowed blade.
The passage vortex structure in bowed cascade is also presented. It can be concluded that a bowed blade can make the passage vortex stable and helps change its structure from loose to compact. Blade bowing is also beneficial to limit the influence domain of the unstable passage vortex core by the stable limit cycle.