Numerical and experimental study of swirling flow in a model combustor

The present paper describes a numerical and experimental investigation of strongly swirling flow in a water model combustion chamber equipped with a swirler of special design. The turbulence models used for the numerical calculations are the standard k-epsilon model, the RNG k-epsilon model and a differential Reynolds stress model (DRSM). In the water model, local mean velocity components and normal stresses are measured using a laser Doppler anemometer. Comparison of numerical predictions against experimental data reveals the superiority of the DRSM over the standard and RNG k-epsilon models. The DRSM captures all the major features of the swirling flow, while the other two:models do not. For instance, both the experimental data and the DRSM predictions reveal complex, interesting flow behaviour: a corner recirculation zone, and a central toroidal recirculation zone connected to a central reverse zone, which persists all the way to the outlet of the chamber. However, the other two turbulence models predict that the swirling flow evolves into a solid-body-rotation-type flow downstream. The RNG k-epsilon model gives very little improvement over the standard k-epsilon model for the swirling flow case Considered. (C) 1998 Elsevier Science Ltd. All rights reserved.