Direct numerical simulation of pollutant adsorption by charged inertial spheroidal particles suspended in a homogeneous isotropic turbulent flow

Injecting adsorbent particles into a turbulent flow containing gaseous pollutants is an effective yet costly method for preventing the release of such toxic substances in the atmosphere. Since adsorbent particles in practical applications often have irregular shapes, determining the optimal particle shape can improve efficiency and significantly reduce the costs associated with the cleaning process. Hence, this study aims to investigate, for the first time, how the shape and structure of adsorbent particles affect the removal rate of gaseous pollutants. This is achieved by coupling direct numerical simulations (DNS) of a charged, spheroidal particle-laden turbulent flow with a mass transfer model. To do this, the turbulent flow and pollution concentration fields are solved in an Eulerian framework using a direct numerical simulation of incompressible Navier–Stokes and passive scalar transport equations, while the dynamics of the spheroidal adsorbent particles is modeled in a Lagrangian framework to track their position and orientation during the simulation. Switching between these frameworks is accomplished through interpolation and averaging methods, and the results are used in modeling the external and internal mass transfer processes for porous spheroidal particles. The results obtained from the set of 45 performed simulations in this study show that, given the operating conditions of the cleaning process, the use of a specific normal distribution of the shape and structure of the adsorbent particles can enhance the effectiveness of the air purification process.