CFD simulation for designing a chlorine gaseous sanitizer treatment system

A 3D numerical model using COMSOL software was developed to simulate the profile of ClO2 gas concentration and bacterial inactivation in treatment chambers with different gas inlets and outlets. The multiphysics simulation based on a finite element method (FEM) included compressible flow, convection and diffusion, and especially, pathogen inactivation codes using Java language were embedded into the program. Finally, each component of the model was coupled and simulated in a transient state. The main fluid stream reached a steady state in a short time because the input speed of ClO2 gas was fast compared to the size of the chamber. Though the chamber was a closed system, compressible air was not observed inside the chamber. Various scenarios with different gas inlet and outlet locations can influence the uniformity profile of increasing ClO2 gas concentration and bacterial inactivation. The optimal configuration was finally found by means of the simulation, and there was a good correspondence in pathogen inactivation profiles between CFD simulation and experiment. This study revealed the computational fluid dynamics (CFD) codes which can help the food processing industry in constructing a scaled-up system and establishing optimum sanitizing treatment conditions. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.