The effect of inflow conditions on the development of non-swirling versus swirling impinging turbulent jets

摘要

In this paper, axisymmetric turbulent jets are investigated numerically with the aim of improving our understanding of the effect of inflow conditions, swirl and near-field impingement on jet development. After presenting an extensive overview of the works published on swirling and non-swirling impinging jets, the Reynolds-Averaged Navier-Stokes (RANS) approach (with different turbulence models) is used to study these flows and validated against experimental data sets. This study then explores the effects of the inlet swirl velocity profiles, namely a Uniform Profile (UP), Solid Body rotation (SB) and Parabolic Profile (PP) on impinging jet development in weakly swirling jets (S <= 0.3) where no vortex breakdown occurs at Re = 23,000 in the near-field (x/D < 2). These conditions are selected so as to avoid the perturbation induced to the flow by a stagnant recirculating (vortex breakdown) bubble and the additional effects, on jet spread, which would likely occur at larger swirl number or delayed jet impingement (x/D >= 2).