Effect of Varying Turbulence and Exit Mach Number on Performance of Fluidically Throttled Nozzle Guide Vanes

A three-passage transonic linear cascade was used to test fluidically actuated variable area turbine (VAT) vanes for performance. The fluidic actuators on these vanes are suction side spanwise slots that reduce the aerodynamic throat area when the active flow control (AFC) is on. To increase engine relevance, these vanes were tested at 2 different freestream turbulence (FST) levels and 3 different exit Mach numbers at baseline (AFC off) and actuated (AFC on) conditions. The exit total pressure was surveyed to understand the impact these conditions had on wake loss. The effectiveness of the mass flow reduction and the wake loss were assessed at these conditions. As free stream turbulence was increased, the core mass flow reduction and effectiveness of the actuator was reduced, however the normalized wake loss coefficient was improved. As the isentropic exit Mach number increased, little effect was seen on the blocking capability of the actuators, but the effectiveness was decreased. The normalized wake loss coefficient increased with increasing exit Mach number.