Flow Separation Control for Low-Pressure Turbine Blade using Vortex Generator Jets

Numerical study of flow separation control is conducted employing Vortex-Generator Jets. This strategy is first tested for the flow past a cylinder at Reynolds number (Re) of 13,400, and then applied to flow in a low-pressure turbine (LPT) cascade for the PAK-B blade geometry at Re = 25,000. A fourth-order accurate compact-difference scheme is used along with sixth-order filtering (C4F6). FDL3DI, a research code developed at WPAFB, is used as the flow solver. A blowing ratio of 2.0 with a skew angle of 90$^{\circ}$ and a pitch angle of 30$^{\circ}$ is employed in the simulations for the aforementioned configurations. The control jets are pulsed with F$^{+}$ = 1.0 for the case of the cylinder, and with F$^{+}$ = 2.33 for the LPT case. The results show a significant decrease in drag on the cylinder after the jets are turned on. The total-pressure loss is calculated in the wake region, at x/D = 3.0, and a reduction of 10{\%} is observed. For the LPT case, the implemented flow separation control strategy totally eliminates the separation and leads to 27.5{\%} reduction in wake total-pressure loss.