Author(s)

E. Eslamian, H. Shirvani & A. Shirvani

Abstract

This study reports the Computational Fluid Dynamics (CFD) results of a swirling flow induced by introducing a helical insert inside a supersonic nozzle. The CFD simulation shows a very complex unsteady, non-axisymmetric flow pattern for the swirl flow inside the nozzle. The flow is investigated by solving the Reynolds averaged Navier Stokes (RANS) equations with k- and Reynolds Stress Model (RSM) turbulence models to predict the flow patterns and the type of swirling flow. Computations are conducted for a range of nozzle pressure ratios with and without swirl inside the converging–diverging nozzle. The study has revealed a new understanding and data for flow features such as shock location, mass flow rate and anisotropic turbulence. Keywords: swirl flow, supersonic nozzle, flow separation, CFD. 1 Introduction Investigation of supersonic flow inside converging–diverging (C–D) nozzles has been the subject of several numerical and experimental studies in the past [1, 2] but there is not that much research on the effect of swirl flow inside C–D nozzles. Swirling flows which are very common in technical applications, such as turbo machinery, cyclones or separators, and they require sophisticated modeling. The effect of swirl inside a nozzle can improve the mixing features of the flow by increasing turbulence and vorticity in the nozzle, which can be useful in combustion injectors and sand blast techniques; also swirl flow will change the shock structure and its interaction with the boundary layer and create a larger separation zone at the exit of a nozzle. These viscous and compressible phenomena affect the flow behavior inside and outside of a nozzle. Since

Keywords

swirl flow, supersonic nozzle, flow separation, CFD.