The Effects of Steady Injection on an Ultra High Lift Vane in a LP Turbine

The application of steady flow injection to control flow separation on the suction side of an ultra high lift low pressure turbine airfoil is presented. The blade lift coefficient of the ultra high lift airfoil at 1.46 Zweifel coefficient is considerably higher than those of conventional airfoils. Blade Reynolds numbers and blade dimensions are comparable to the first stages of aero engine low pressure turbines. The ultra high lift vane row is installed into a three stage low Mach number turbine test rig. Steady flow injection through suction side streamwise holes is investigated: with an angle to the surface of 45 deg. The pitch to diameter ratio is 10. The variation of the blowing ratio allows a closer study of the influence and effects occuing due to flow injection. Results show that steady flow injection can almost completely eliminate separation on the suction side. For four different blowing ratios blade pressure distribution and exit flow area traverse shows rising stage loading. A maximum of one percent change in flow exit angle was measured. The experimental results reveal that the injection jets only locally suppress the separation. This results in a spanwise variation in lift and trailing edge shed vortical structures.