LAUSR

Abstract Three-dimensional flow regimes in the T-jet reactor were experimentally studied by planar laser induced fluorescence (PLIF) at 50 ≤ Re ≤ 560. The visualization images on cross-sections at different Reynolds numbers were obtained to investigate the engulfment flow regime and its influence on the mixing. With unsteady engulfment flow, periodic vortex merging in the impingement plane is observed and characterized. Results show that the merged vortex passes through the channel and causes periodic oscillation in the chamber. The effect of the confinement of the chamber wall on the engulfment flow regime was discussed. Large eddy simulation is also used to investigate the variation of pressure and velocity of the oscillation caused by the unsteady engulfment flow. Time-evolution and average of Intensity of Segregation (IOS) were quantitatively analyzed to reveal the mixing mechanism. Results show that the oscillation of vortex merging in the unsteady engulfment flow regime significantly improves the mixing performance.