ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Aeration-assisted venturi cavitation: a combined CFD and experimental study on cavitation dynamics and COD reduction

Esmail Noshadi, Maziar Changizian, and Morteza Behbahani-Nejad

Department of Mechanical Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

E-mail: E-noshadi@stu.scu.ac.ir

Received: 28 December 2025  Accepted: 24 May 2026

Abstract:

Hydrodynamic cavitation (HC) has recently gained attention as a promising technique for wastewater treatment due to its strong oxidation capability. However, the influence of aeration on the internal structure of cavitation and its contribution to pollutant removal performance remains insufficiently understood. This study employs a combined numerical–experimental approach to investigate both the hydrodynamic development of cavitation and its practical impact on chemical oxygen demand (COD) reduction. In the first stage, a 3D computational fluid dynamics (CFD) model based on the mixture approach and the k–ε turbulence model is used to analyze cavitation under varying inlet pressures (2, 2.5, and 3 bar) and air injection rates (5, 10, and 15 l/min). The simulations demonstrate that increasing aeration enhances the occupied vapor volume fraction and expands the cavitation zone inside the venturi throat. In the second stage, a hydrodynamic cavitation reactor is experimentally operated to examine how these aeration-induced modifications in cavitation translate into COD reduction. The findings show that the highest COD removal (17.46%) occurs at 3 bar and 15 l/min of aeration, confirming that stronger cavitation activity results in more effective pollutant degradation. Overall, this work establishes a direct link between cavitation enhancement and its treatment performance, providing both mechanistic insight and practical guidance for optimizing aeration-assisted hydrodynamic cavitation systems.

Keywords: Venturi; Cavitation; Wastewater treatment; Chemical oxygen demand (COD); Numerical simulation; ANSYS fluent

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05111-x

Chemical Papers 80 (10) 12001–12021 (2026)