NUMERICAL AND EXPERIMENTAL STUDY OF TURBULENT PROCESSES AND MIXING IN JET MIXERS

摘要

Velocity and passive scalar fields in a co-axial jet mixer have been investigated both experimentally (LIF and LDA) and numerically (LES) in a single phase incompressible flow at different flow rate ratios, flow densities, Reynolds numbers and temperatures. Two flow regimes with and without recir-culation zone are considered. The flow in the recirculation zone is unsteady and contains coherent vortex structures which enhance sufficiently the mixing of scalars. Different SGS closure models have been tested by comparing with experimental data. The best results were achieved using the dynamic mixed model. The experimental and numerical investigations showed that the mixing is mostly influenced by the flow rate ratio. The effect of other parameters is negligible.