A convenient method to validate the gas flow of a CFD-CT simulation applied on a packed bed used in gas biofiltration through residence time distributions

In this work, the validation of a Computational Fluid Dynamics (CFD) model coupled with a 3D computational tomography (CT) bed description of the gas flow field inside a packed column used for gas biofiltration was conducted using a low-cost metal oxide sensor. The validation was carried out in terms of gas residence time distribution (RTD), which was constructed from the sensor measurements using a mathematical model to filter the transient signal behavior. The coupled CFD-CT model was used to obtain the steady-state velocity field inside the packed bed by numerically solving the incompressible Navier-Stokes equations. Later, the tracer injection was simulated over the obtained velocity field by solving a transport equation for a passive scalar. Finally, the experimental and simulated RTD were compared to validate the model. The comparison between the experiments and the CFD simulations showed good agreement between both shapes of the RTD distribution with a relative difference of 4.167% for the mean RTD, denoting the potential of the proposed methodology to validate the CFD model and predict the moments of the RTD. This methodology can become a very useful tool for the validation of CFD simulations with the final purpose of studying the processes at the microscale undergoing inside packed bed biofiltration reactors.