Study of film cooling characteristics on plug of two-dimensional (2-D) plug nozzle

The heat load of 2-D plug nozzle sharply increases under the afterburning condition, therefore, it is necessary to introduce cold air to cool the plug. Based on subscale model experiment verification, a numerical simulation of full-scale model was performed to investigate the effect of plug film cooling on the aerodynamic and cooling performance of 2-D plug nozzle. The effects of total pressure ratio of inlets, diameter of film holes and perforated percentage of film holes were analyzed by contrast. The calculation results indicated that: within the range of the study parameters, film cooling made the plug surface temperature significantly drop and had a little effect on the thrust coefficient of the nozzle. Compared with the case without cooling, the total pressure ratio of inlets increased from 1.02 to 1.20, the surface temperature of the plug decreased by 20% to 45% and the total pressure recovery coefficient decreased by 0.22% to 1.26%. A lower channel pressure and a bigger film outflow resistance were caused by a higher perforated percentage of film holes, which even caused the hot gas backflow in the tail of plug. Considering the cooling air discharge condition of the whole plug surface, a small perforated percentage of film holes showed more advantages. Reducing the diameter of film holes meant increasing the amount of film holes and the film coverage, thus making the cooling effect slightly enhanced. © 2024 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.