Study on the Turbine Stator Secondary Flow Using Moving Cylinders to Simulate Rotating Blades

Computational fluid dynamics method (CFD) was used to solve the three-dimensional flowfield of one-stage turbine stator cascade with a large turn angle.The stator's pneumatic characteristics and the secondary flow were analyzed in detail.Moreover,grid independence was considered during the simulation.As a result,the secondary flow from the pressure surface to the suction surface enhances gradually along with the flow direction,which causes the head loss and the outlet angle to fluctuate.Firstly,high head loss arises at the region near the endwall and stator surfaces,the reason is that the transverse pressure gradations in flowfield strengthen and the secondary flow region expands in this instance.At the same time,the strength of the secondary flow increases when the stator height decreases or the inlet attack increases.In particular,moving cylinders replace the rotating blades which are situated at upstream and downstream of the studied stators.The head loss varies greatly when the inlet cylinder wake is situated at different positions.Also,the cylinder rows downstream have the apparent effect on the oblique zone of the stators.It provides an important reference for the optimization and study on the inner flowfield of turbomachinery.