Study on the Effects of Aft Deck Geometry on Plume Shield Ratio

In this study, we investigated the effects of aft deck geometry on the nozzle of a turbofan engine applicable to an unmanned aerial vehicle. An experimental facility, consisting of a turbofan engine, test stand, and data acquisition system, was set up to obtain the computational fluid dynamics boundary conditions. Reynolds-averaged Navier–Stokes (RANS) equations coupled with the k-omega shear stress transport turbulence model were implemented using the STAR CCM + commercial software. When the aft deck length is extended, the aft deck increases the plume length; however, it is also shown that the aft deck could improve the plume shield ratio by approximately a maximum of 7–8%. Furthermore, when the aft deck’s lower plate was not sufficiently long, the shielding efficiency was small and thrust reduction was the highest. The aft deck length is an important variable in thrust performance and plume shielding rate and was found to help reduce the exposed plume length.