Configuration of a Premixer and Grooved Surface to Intensify the Micromixing Performance of a Spinning Disc Reactor

Abstract

A premixer and grooved surface are designed to improve the micromixing performance of a spinning disc reactor (SDR). The inlets of the impinging jet provide an initial premixing of the two streams. The effects of premixing and grooved surface on the overall micromixing performance at different conditions are investigated systematically. The results show that premixing and trapezoidal groove surface could greatly intensify the global micromixing performance of SDR. Increasing the rotation speed and flow rate also significantly improves the micromixing effect. When the disc distance is lower than 0.80 mm, an extremely low inter disc distance deteriorates the micromixing. The effect of premixing on the micromixing performance of low viscosity streams is more significant than that of the spinning disc itself. However, for high viscosity streams, the micromixing performance strongly depends on the spinning disc. The flow patterns in the designed SDR were further studied. Three flow patterns, including film flow, film− filament transitional flow, and filament flow, were observed in SDR with a stator disc. High rotational speed, large disc spacing, and low volumetric flow rate are conducive to the formation of filament flow rather than film flow. Predicative dimensionless criteria for flow patterns were established. The results provide meaningful information for further intensifying the micromixing performance of SDR.

Characterization of Micromixing Intensification of Impinging Jet Flow on a Spinning Disk Reactor with a Structured Surface

“…The evaluation of mixing times should consider the influence of reactor type, mixing models, kinetic parameters, and operating conditions. In this paper, the τ mix of the grooved disks ranges from 0.04 to 2.19 ms, with a magnitude that is generally consistent with the other spinning disk reactors. ,, Notably, under the current experimental conditions, it exhibits the lowest value, which is attributed to the disk with groove R32. That means the radial grooves can effectively intensify the micromixing performance of SDR.…”

“…Meanwhile, the effect of a premixer relies on the viscosity of fluid. For low viscous fluid, the premixing is more significant than that of the disk, while the mixing performance strongly depends on the disk surface for high viscous fluids . The cylindrical or elliptic-cylindrical spoiler arrays also can intensify the mixing in the photochemical process and exhibit superior photon absorption rates .…”

“…For structured surfaces, the concentric grooved disk can influence the film behavior by continual creation and breakdown of the boundary layer, providing an improved mixing efficiency compared to the smooth disk within a certain range of speeds . The trapezoidal grooved surface can greatly intensify the global mixing performance, especially for high viscous fluids . In low shear regions (i.e., under conditions of a low flow rate or low disk speed), the grooves exhibit greater advantages as the disrupted flow triggers the passive mixing effects and thus results in the generation of more nuclei compared to smooth surfaces .…”

“…The best operating conditions can be determined from the kinetic data and experimental procedure. − Following the competitive consecutive scheme, the second Bourne reaction refers to the simultaneous diazo-coupling of 1-naphthol and 2-naphthol with diazotized sulfanilic acid in a basic environment, also known as the diazo-coupling of naphthols . Although the kinetics of the second Bourne reaction have been carefully improved, the Villermaux–Dushman method has gained popularity and widespread application due to its simplicity in experimentation and analysis. ,,, …”