Effect of Incidence on Secondary Flows in a Linear Turbine Cascade

Abstract

The effect of incidence on the generation and growth of secondary flows in a linear turbine cascade was studied in the present investigations using a Variable Density Cascade Tunnel at an exit Mach number of 0.43 and a Reynolds number of 8 × 105. The angles of incidence chosen were +15°, +50, 0°, −5° and −8.5°. The flow field was surveyed at five axial stations from cascade inlet to exit with a view to understanding the development of the secondary flow with the help of the variation of mass averaged total pressure loss coefficient and the contours of local loss coefficients in the pitch and spanwise directions. The total pressure loss coefficient and the net secondary loss coefficient have shown a steady growth along the cascade upto about 74 of the axial chord from the leading edge and thereafter rose very rapidly. The incidence is found to have an effect on the passage vortex and the loss cores due to the inlet boundary layer.

Research on Effects of Incidence to Turbine Guide Cascade Aerodynamic Performance

“…It was inverse in the case of positive incidence angle: the intensity of wall corner vortex and passage vortex was strengthened, and the passage vortex and shedding vortex moved to the center of the blade. Therefore the flow loss increased [5]. But only incidence angle was reduced within a certain range, the secondary flow could be reduced.…”

Inlet Flux Influence to Aerodynamic Performance of Steam Turbine Vane Cascade

“…So we must research the off-design working performance of steam turbine cascades. Every country engineering had conducted many work to improve the cascade efficient (Murt et al, 1994;Yamamoto et al, 1994). This study mainly researches the influence to cascade aerodynamic performance by inlet flow rate change and the results can provide the theoretical support to improve the aerodynamic efficient of cascade.…”