11th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
A detailed analysis of the effect of incoming periodic wakes on the aerodynamic performance of a very-high-lift, mid-loaded low-pressure turbine airfoil (T106C) is presented. This experimental study was performed on a large scale linear cascade in the VKI S-1/C transonic wind tunnel, operating at a fixed exit isentropic Mach number equal to 0.65, covering a range of exit isentropic Reynolds numbers (90,000 200,000 based on chord length) and at low inlet free-stream turbulence intensity (0.8 %). The simulation of incoming periodic wakes was realized by means of a disc equipped with bars rotating at high speed upstream of the leading edge plane, allowing an engine representative simulation of the operating conditions (flow coefficient, reduced frequency, wake width and depth) encountered in low-pressure turbines of modern aero-engines. The aerodynamic performance of the airfoil is presented based on measurements performed by means of on-blade static pressure taps, multi-hole probes traversed upstream/downstream of the cascade and on-blade hot-film sensors. Some features of the multi-mode transition germane to unsteady wake-boundary layer interactions in a lowpressure turbine environment are also discussed for specific cases.