Numerical investigation of three-dimensional effects of cavitating flow in a venturi-type hydrodynamic cavitation reactor

TL;DR

This study uses advanced numerical simulations to analyze the three-dimensional flow physics of venturi-type cavitating reactors, revealing insights into turbulence and cavitation-vortex interactions crucial for environmental applications.

Contribution

It compares 2D and 3D DES models for venturi cavitation, highlighting the importance of 3D analysis in capturing local turbulence phenomena and flow physics.

Findings

DES models accurately predict local turbulence in 3D simulations

Significant discrepancies found between URANS and DES models

Baroclinic torque plays a key role in cavitation-vortex interactions

Abstract

The concept of Hydrodynamic Cavitation (HC) has emerged as a promising method for wastewater treatment, bio-diesel production and multiple other environmental processes with Venturi-type cavitation reactors showing particular advantages. However, numerical simulations of a venturi-type reactor with an elucidated explanation of the underlying flow physics remain inadequate. The present study numerically investigates and analyzes the flow inside a venturi-type reactor from both global cavity dynamics and localized turbulence statistics perspectives. Some models in the Detached Eddy Simulation (DES) family are employed to model the turbulence with the study initially comparing 2D simulations before extending the analysis to 3D simulations. The results show that while URANS models show significantly different dynamics as a result of grid refinement, the DES models show standard flow dynamics associated with cavitating flows. Nevertheless, signifi- cant discrepancies continue to exist when comparing the turbulence statistics on the local scale. As the discussion extends to 3D calculations, the DES models are able to well predict the turbulence phenomena at the local scale and reveal some new insights regarding the role of baroclinic torque into the cavitation-vortex interaction.The findings of this study thus contribute to the fundamental understandings of the venturi-type reactor.