Numerical and Experimental Investigations of the Dynamics and Structure of the Recirculation Zone in a Coaxial Jet Mixer

摘要

Mixing and particular mixing in a coaxial jet mixer has been a subject of investigations for a long time References concerning this subject can be found in [1], [2] and [3]. The classical coaxial jet mixer consists of a pipe of diameter D with a coaxially arranged center pipe with a nozzle diameter d. Depending on the flow rate ratio there are two typical modes. Following Barchilon and Curtet [1] if D/d < 1 + Vo/Vd the flow is similar to a free jet regime (henceforth j-mode). Otherwise we have a strong recirculation zone close the nozzle (henceforth r-mode) (Fig I). The recirculation enhances the mixing efficiency drastically so that the homogenous state is reached after four or five pipe diameters downstream of the nozzle what makes this mixing regime attractive for various homogenization devices. The present work is focused on investigations of flow physics within the recirculation zone in the r-mode with experimental and numerical tools.