Experimental study of surface heating by a high speed exhaust plume

Abstract

Airframe surface heating by gas turbine plume is an ongoing issue in aerospace applications. This paper presents the practicability of a smaller scale system based on a micro gas turbine which offers verisimilitude and realism to the actual airframe surface heating by a full scale engine exhaust plume flow. A thin flat plate made from 7075-T6 aluminium alloy was placed at X=7D downstream of the nozzle exit of the gas turbine. Nozzle exit flow temperature ranged from 850K to 920K and Reynolds number over the sample plate ranged from 3.8×104 to 2.6×105. The average Nusselt number was found to be correlated to CRemPrn with m=0.42, n=0.33, C=0.094 for parallel plume flow over the sample plate at X=7D and Z=0D. It was also found that coefficient C can be scaled by velocity magnitude ratio with respect to the plume centre if the sample was positioned away from the centre of the jet plume. Heat transfer by infrared radiation was found to be less than 2% compared to the overall heat flux.