Effects of deflected trailing edge on the aerodynamic performance of high-lift low pressure turbine cascades

To reduce the energy loss of high-lift low pressure turbine (LPT) and improve the aerodynamic performance, numerical simulation method was used to study the effects of trailing edge shapes on the aerodynamic performance of high-lift LPT L2F cascades. The effects of three trailing edge shapes, deflected trailing edge, increasing trailing edge thickness and the Gurney flap on the energy loss and flow were studied. It is shown that the three trailing edge shapes all can increase flow turning angle, decrease energy loss coefficient at low Reynolds number (Re) and increase the energy loss at high Re, however the deflected trailing edge is more effective than the others to improve the aerodynamic performance of the LPT cascades. Deflected trailing edge decrease energy loss by 16.5% at Re of 20 000 and free-stream turbulence intensities (FSTI) of 3.3%. The three trailing edge shapes deflected the main flow, accelerate boundary layer flow on the suction side, and suppress the flow separation, which tend to decrease the energy loss. However the three trailing edge shapes enhance the mixing flow behind the trailing edge, which tend to increase the energy loss.