The impact of the purge flow injection on aerodynamics and film cooling effectiveness of a three-stage high pressure turbine with non-axisymmetric endwall contouring has been experimentally investigated. As a continuation of the previously published work involving stator-rotor gap purge cooling, this study investigates film cooling effectiveness on the first stage rotor contoured platform due to a coolant gas injection. Film cooling effectiveness measurements are performed on the rotor blade platform using a pressure sensitive paint (PSP) technique. The present study examines, in particular, the film cooling effectiveness due to injection of coolant from the rotor cavity through the circumferential gap between the first stator followed by the first rotor. Efficiency and performance experiments were conducted with and without cooling injection to show (a) the impact of endwall contouring on the turbine efficiency and (b) the impact of film cooling injection in association with the endwall contouring.
The experimental investigation is carried out in a three-stage turbine facility at the Turbomachinery Performance and Flow Research Laboratory (TPFL) at Texas A&M University. Its rotor includes non-axisymmetric endwall contouring on the first and second rotor row . The turbine has two independent cooling loops. Film cooling effectiveness measurements are performed for three coolant-to-mainstream mass flow ratios of 0.5%, 1.0% and 1.5%. Film cooling data is also obtained for three rotational speeds, 3000 rpm (reference condition), 2550 rpm and 2400 rpm and compared with non-contoured endwall data.