Experimental and modeling study on meso- and micromixing in the rotor–stator spinning disk reactor
Arturo N. Manzano Martı́nez, Rick D. M. Jansen, Keegan Walker, Melissa Assirelli, J. van der Schaaf
Abstract
The micromixing efficiency in the rotor–stator spinning disk reactor is studied for increasing injection flow rates of limiting reagent. Using both the Villermaux–Dushman method and second Bourne reaction, an increase in segregation index was found with increasing injection flow rate. Mechanistic models describing micro- and mesomixing were reviewed and implemented to describe the effects of increasing segregation index with increasing injection flow rate. A simplified turbulent-dispersion model was found to describe this trend effectively. A new parameter, based on a logistic function, was proposed to couple mesomixing by turbulent-dispersion and micromixing by engulfment on basis of the ratio of the characteristic times for turbulent-dispersion and engulfment. For injection flow rates where micromixing was calculated to be dominant, the engulfment model was implemented. An experimental relation was fitted to describe the dependency of the local energy dissipation rate on the turbulent diffusion coefficient in the rotor–stator spinning disk reactor. For the Villermaux–Dushman test reaction and the second Bourne reaction, discrepancies were found in the local energy dissipation rates experienced by the reaction zone. These discrepancies were analyzed on basis of the reaction times of both test reactions. The effect of the reaction time was accounted for by introducing a time-dependent local energy dissipation rate, which could be used to study the energy dissipation rate profile in the rotor–stator spinning disk reactor.