Evaluation of disinfection and cavitation performance of a cylindrical rotational hydrodynamic cavitation reactor: Influence of key geometric parameters of the cavitation generation unit

Abstract

Hydrodynamic cavitation offers a promising technological platform for diverse industrial applications, including water treatment and chemical process intensification, and holds significant potential for widespread adoption in future advanced processing systems. This study investigates the disinfection efficacy of a novel Cylindrical Rotational Hydrodynamic Cavitation Reactor (CRHCR) and elucidates the underlying mechanism of Escherichia coli (E. coli) inactivation induced by hydrodynamic cavitation. Microscopic analysis of E. coli post-treatment revealed that the intense mechanical shear forces produced by collapsing bubbles are primarily responsible for bacterial inactivation. In addition, the influence of key geometric parameters of the cavitation generation unit on the hydrodynamic performance of the CRHCR was systematically examined. The results demonstrate that rectangular grooves exhibit superior cavitation performance compared to trapezoidal and triangular configurations. An increase in groove width and number correlates positively with enhanced cavitation intensity. In contrast, changes in groove depth, oblique tooth angle, and groove angle exhibit a non-linear trend, with cavitation performance initially increasing with as these parameters rise, followed by a decline once optimal thresholds are exceeded. Optimal cavitation performance was attained with a groove depth of 2 mm, an oblique tooth angle of 68°, and a groove angle of 5°. The observed variation in cavitation efficiency across different CRHCR configurations is attributed to the distinct geometries of the cavitation generation units, which modulate the distribution of low-pressure zones. These findings provide valuable insights into the structural design, theoretical understanding, and practical application of advanced hydrodynamic cavitation systems.