Abstract
•Effect of geometry on three-dimensional flow in T-jet reactors is studied using PLIF.•The oscillation of unsteady engulfment flow in different T-jet reactors is investigated.•Mixing qualities in different T-jet reactors are compared.
T-jet reactors have been widely used in micro/mini reactors for their simple geometries and rapid mixing. Following our previous report (Zhang et al., Chem. Eng. J., vol. 358, 2019, 1561–1573), the present study describes the flow regimes in T-jet reactors with different geometrical parameters at 50 ≤ Re ≤ 400 by using planar laser induced fluorescence (PLIF). The influences of the headspace height (H/h), the outlet aspect ratio (W/w), and the depth of the reactor (w/h) on the origination and evolution of steady and unsteady engulfment flow have been investigated in detail, where h is the inlet height, w is the reactor depth, W is the outlet width, and H is the headspace height. A comparison of the critical Reynolds number (Re) of steady engulfment flow between current work and previous investigations in the literature is presented. The mixing performance of various T-jet channels has also been analyzed using the Intensity of Segregation (IOS). Results show that, the intertwinement of two inlet streams is weakened as the headspace height increases, and the unsteady engulfment flow disappears for H/h ≥ 0.3. The outlet aspect ratio influence the evolution of engulfment flow in the chamber and the unsteady engulfment flow vanishes as W/w reaches 8. Besides, the engulfment of two inlet streams decreases and the unsteady engulfment flow disappears whether the reactor depth increases to w/h = 2 or decreases to w/h = 0.5.