Mixing Characteristics of Elliptical and Rectangular Subsonic Jets with Swirling Co-flow

Abstract

AbstractThis paper presents a computational analysis of effects of swirling co-flow and non-circular subsonic compressible inner jets on centerline velocity decay, mass entrainment and jet spreading rate. Three different exit shapes of elliptical, rectangular and circular inner jets were compared for three different co-flow conditions such as no co-flow, straight co-flow and swirling co-flow. Co-flow is issuing from a circular annular duct. Swirling co-flow is created in the co-flow duct by introducing a swirler with stationary angular vanes of 50° oblique to the jet axis. Reynolds number of inner jet is calculated based on its equivalent diameter as 200342. It is found that the swirling co-flow has strong influence on the boundary condition of inner jet and alters the major features of the jet such as jet potential core length, centerline velocity decay rate and jet spread rate. Streamwise corner vortices of different jet conditions have been captured using velocity vector plot to show the effect of swirling co-flow on the jet flow field. Swirling co-flow with elliptical inner jet exhibits higher velocity decay rate and jet spreading rate than the equivalent area circular and rectangular jet.