Mixing in the confined vortical flow in non-aligned T-jets reactors

Abstract

In this work, flow dynamics and mixing performances in a non-aligned T-jets reactor are experimentally studied within a Reynolds number (Re) range of 50–160. Plane Laser-Induced Fluorescence (PLIF) is used to measure concentration fields and explore underlying vortical flow structures. Two vortex rings are identified in the mixing channel of the reactor at Re≥90, and the fluid pulsation induced by the vortex ring is demonstrated. The mixing in the reactor is qualified by an area-based distribution of mixing intensity, and the scale and intensity of segregation. Results show that the scale and intensity of segregation are reduced as the vortex ring appears, and the overall mixing is closely associated with vortex rings and the fluid pulsation, of which the former dominates. Further insight into the mixing is obtained by analyzing the decay time of the fluid. It is found that long decay time of the fluid in vortex rings causes the formation of well-mixed regions, and the concentration decay time in the second vortex ring is more than twice that in the first vortex ring despite the smaller size of the second vortex ring.