Utilization of the Transient Liquid Crystal Technique for Film Cooling Effectiveness and Heat Transfer Investigations on a Flat Plate and a Turbine Airfoil

U. Drost, A. Bölcs, A. Hoffs
1997 Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration   unpublished
The transient liquid crystal technique has been used to measure film cooling effectiveness and heat transfer on a flat plate in a free jet, and a turbine airfoil in a linear cascade. A multiple-test regression method has been developed for the data reduction, considering a transient coolant temperature evolution. Flat plate film cooling was investigated for a single row of 35° inclined holes at Math numbers of 0.3 and 0.5, and two turbulence intensities. Downstream of injection heat transfer
more » ... increased in-between the holes due to enhanced turbulence caused by the shearing of the coolant and the mainstream. At higher turbulence intensity the range of blowing ratios was broader as lift-off was delayed. Film cooling measurements on the airfoil were conducted at enginerepresentative flow conditions. A maximum effectiveness of 0.3 behind injection was observed on the suction side, with slightly higher values for a double row in comparison to a single row configuration. Due to a high coolant momentum, the effectiveness on the pressure side was very low at about 0.05 for a single row configuration. NOMENCLATURE ep sped5c heat capacity [JAEN d coofing hole (remoter [rum] f fraciancljlizl DR density ratio Nip, G blowing ratio pcodpits,
doi:10.1115/97-gt-026 fatcat:ob4xh2wb3nbghae33n6z5i26xa