Effects of fuel injection angle on mixing performance of scramjet pylon-cavity flameholder

Parent resource - MTP - Mixing Enhancement

DOI - 10.1063/5.0026125
Journal Name - Physics of Fluids
Publisher Name - AIP Publishing
Document Type - journal-article

Paper Abstract- A numerical investigation on the effects of fuel injection angle on various mixing parameters within a pylon-cavity aided supersonic combustor flameholder under non-reactive flow conditions is performed. The computational model based on Reynolds-averaged Navier–Stokes equations for compressed real gas is solved by a coupled, implicit, second-order upwind solver with a two-equation Menter’s shear stress transport turbulence model. The steady simulations are experimentally validated using wall pressure data, two-dimensional (2D) velocity field, and fuel mass fraction. Three distinct fuel injection locations at the cavity floor are used for sonic hydrogen fuel injection at 90° and 45° injection angles, with a crossflow Mach number of 2.2. The results show deeper fuel jet penetration capability for the transverse injection when compared to an angled injection, whereas better mixing capability is observed for the latter. The fuel jet vortex pairs formed due to the interaction of the surrounding cavity flow with the barrel shock play a vital role in the mixing mechanisms. The lower pressure regions due to the barrel shock result in the formation of a secondary fuel jet vortex pair. The Kelvin–Helmholtz instability observed between the counter-rotating vortex pairs results in the formation of smaller eddies, which enhance the fuel dispersion and transport.