Numerical study of active flow control using jet-flap for a low-pressure turbine cascade

Based on Menter's SST k^-ω turbulence model coupled with Langtry-Menter transition model,the control mechanism of jet-flap,an active flow control method for PAK-Blow-pressure turbine blade profile,was numerically investigated under different flow conditions including different cascade inlet Reynolds numbers,free stream turbulence levels,and cascade outlet Mach numbers.The results show that the jet-flap effectively reduces flow loss when PAK-Bprofile is stalled.With jet flow mass fraction equal to 2%,relative to the baseline,the energy loss coefficient reduced by about 40%;the flow turning angle increased by about 5%;and the inlet primary flow mass reduced by about 10%.When the flow was not stalled,the control could be ineffective.The results also show that the jet-flap delays boundary layer transition on adjacent blade profile suction side, which in turn delays the boundary layer reattachment.