CFD Analysis of Supersonic Coaxial Jets on Effect of Compressible Spreading Rates

Prevailing high-speed air-breathing propulsion systems invariably banks on coaxial jets which plays a vigorous role in stabilization of flames and combustion emission. Coaxial jets have applications in supersonic ejectors, noise control techniques and enhancement of mixing. Coaxial jet nozzles regulate spreading rates by developing virtuous mean flow and shortening primary flow potential core length. In the present paper, twodimensional coaxial jet profiles of different area ratios are designed and analyzed. The models were designed in ANSYS Design Modeler and the numerical simulation was done in ANSYS FLUENT 14.5 using the two dimensional density based energy equation and transition SST turbulence model with primary supersonic flow and secondary subsonic flow. The contours of turbulent intensity, acoustics power level and axial-velocity are investigated along the flow direction. This study shows that increasing the area ratio results in varying turbulence which in turn varies the potential core length, acoustics power level, turbulent kinetic energy and noise generation.