Numerical study of flow in low-pressure turbines with undulated suction surface

The low-pressure turbine is an important component of the aero engine, and its efficiency greatly influences on the performance of the aero-engine. In order to improve the efficiency of low-pressure turbines, flow control methods can be adopted to overcome the large adverse pressure gradient in the passage of high-load blades, suppress the flow separation at the rear of the suction surface, thereby reducing losses in low-pressure turbines. Based on the understanding of the separated flow mechanism on the suction surface, a new passive control method using undulations on the suction surface to suppress the separated boundary layer is proposed in the current study. It is found that the counter rotating vortices generated by the undulation is attributed to the suppression of the separation bubble, reductions in the loss coefficient and the deviation in the exit flow angle by 15% and 23%, respectively.