Effect of film cooling structures on the cooling characteristics of plugs for two-dimensional (2-D) plug nozzle

Abstract

Based on a turbulence model experimental validation, some numerical simulations were conducted to investigate the effect of plug film cooling on cooling and aerodynamic characteristics for a 2-D plug nozzle. In this study, two cooling schemes namely the half-covering and full-covering film cooling were designed and involved. For each cooling configuration, the effects of perforated percentage (ranged from 0.5% to 2.0%) and non-dimensional inlet total pressure (ranged from 1.02 to 1.20) of coolant on the cooling and aerodynamic performances are discussed separately. The results confirm that an obvious reduction of plug temperature is achieved under both cooling schemes. While the full-covering film cooling configuration performs better, especially at the plug trailing edge where shock waves occurred. Within the scope of the investigation, a small perforated percentage of 0.5% is favorable due to its superior ability to improve the pressure difference between mainstream and coolant; inversely, a big perforated percentage leads to the coolant flow resistance increasing, which may cause the mainstream to flow back at the plug trailing edge. Rising the inlet total pressure of coolant could enhance the cooling performance but also deteriorate the aerodynamic performance of nozzle. Specifically, compared with the case without cooling configuration, the non-dimensional inlet total pressure of coolant ranged from 1.02 to 1.20, the surface temperature of plug decreased by 20% ～ 45%; the total pressure recovery coefficient decreased by 0.22% ～ 1.26%.