On the Calculations of Flat Plate Film Cooling Effectiveness

Abstract

Film cooling is vital to gas turbine blades to protect them from high temperatures and hence high thermal stresses. Improvements have been made to the shaping of the cooling hole to provide higher heat transfer effectiveness. The present study of the impact of the film cooling turbine to protect from high temperatures through the Parametric study of blowing ratio , stream wise angle and the shape of hole on the film cooling effectiveness . Has been studied the following cases three blowing ratios 0.45, 1 and 2, the three stream wise angle of 30, 60 and 90 and study the impact of changing of lateral and forward diffusion angles on the hole cooling from 0 to 15 degrees on the film cooling effectiveness on adiabatic tested flat plate. Using computational fluid dynamics software FLUENT ® and choosing the standard k-ε model. It was concluded the maximum centerline effectiveness with blowing ratio occurs at stream wise angle 30 on flat plate surface, the optimum blowing ratio for arrow of 30 degree jets is around 0.6, relatively less for a row of 60 degree jets is around 0.5 and relatively less for a row of 90 degree jets around 0.4 and the highest cooling lateral effectiveness is obtained in the case of LFDSA-15-15 with fan-shaped diffuser exists by 15-digree divergence angles on both lateral sides at all blowing ratio. NOMENCLATURE DHole diameter (m) L Hole length (m) L1Hole metering section length L2Hole diffused section length M Blowing ratio,

Numerical simulation of supersonic film cooling in a rearward-facing slot

“…Film cooling is typically applied to turbine engines, 1 where cooling air is exhausted through small holes drilled into the blade, 2,3 which can have a higher turbine inlet temperature to improve the turbine performance. Moreover, in rocket engines, 4 film cooling can be used alone or in combination with regenerative cooling to protect the thruster wall.…”