Numerical Study of Active Flow Control for a Transitional Highly-Loaded Low-Pressure Turbine

摘要

Active control was simulated numerically for subsonic flow through a highly-loaded low-pressure turbine. At a nominal Reynolds number of 25,000 based upon axial chord and inlet conditions, massive separation occurred on the suction surface of each blade. Vortex generating jets were then used to help mitigate separation, thereby reducing wake losses. Computations were performed using both steady blowing and pulsed mass injections. The numerical method utilized a centered compact finite-difference scheme to represent spatial derivatives in conjunction with a low-pass Pade-type non-dispersive filter operator to maintain stability. Calculations were carried out on a massively parallel computing platform, using domain decomposition and a high-order overset grid approach. Features of the flow fields are described, and simulations are compared with each other, with available experimental data, and with a previously obtained baseline case for the non-controlled flow. Active flow control resulted in a reduction of the wake total pressure loss coefficient of 53-56%.