CFD simulation optimization of a swirling vortex cavitator and its oxytetracycline degradation characteristics: kinetics and degradation pathway

Vortex cavitation may be harnessed to intensify many industrial processes. It is essential to develop a highly efficient vortex cavitator for refractory organics degradation. In the present work, a novel swirling vortex cavitator designed with a special structure of six vortex cavities and spiral flow passages was optimized using computational fluid dynamics (CFD) method by the aid of Gambit software and ANSYS fluid simulation software, and its oxytetracycline degradation characteris­ tics were investigated. The optimized vortex cavitaor was superior to the original vortex cavitator resulting from more hydroxyl radicals generated during operation and higher oxytetracycline deg­ radation efficiencies. The degradation efficiency was 89.52% and 92.41% of about 2.0 mg/L initial concentration of oxytetracycline in 10 L solution at 80 min by the original and optimized swirling vortex cavitator, respectively. The optimized vortex cavitator also showed good oxytetracycline deg­ radation ability in aquaculture simulation wastewater. All the degradation processes followed the second­order kinetics model. In the two degradation pathways, multiple by­products were gener­ ated by dealkylation, deamination, dihydroxylation and ring­opening induced by vortex cavitation effect.