Influence of exit angle on sweeping jet film cooling effectiveness

This paper experimentally investigates the influence of the nozzle exit angle on sweeping-jet film cooling effectiveness. These geometries are based on a fluidic oscillator design in which oscillating movements in the fluid jet occur without control and solely through friction. The geometries are installed in a flat plate setup featuring varying nozzle exit angles and are compared to the 7-7-7 baseline geometry. The film cooling effectiveness is determined using an infrared measurement of the adiabatic wall temperature on the flat plate at various blowing ratios and a constant density ratio ( $$DR = 1.1$$ ). The measurements show that with increasing the nozzle exit angle of the fluidic oscillators, lateral cooling increases, but the center downstream is cooled less effectively. Integrated across the entire measuring field, the oscillators with small nozzle exit angles achieve a higher area-averaged film cooling effectiveness than the 7-7-7 geometry.