Carrier-phase DNS of iron particle cloud combustion in a highly turbulent shear layer

Carrier-phase direct numerical simulations (CP-DNS) of a three-dimensional turbulent shear- and mixing-layer are presented. DNS enables detailed investigation of complex multiphase turbulent reacting systems that are difficult to study experimentally; however, the reliability and reproducibility of such simulations remain uncertain and are potentially sensitive to the underlying numerical treatment. Given this, the simulations are cross-validated against DNS data by Luu et al. (Flow Turbul. Combust. 2024), first in a statistical sense and then, for the first time, by direct comparison of the instantaneous realizations of the two DNS. A further DNS is then presented for a higher Reynolds number at twice the grid resolution. This represents the most resolved carrier-phase DNS of such systems to date and enables higher turbulence conditions that better represent realistic burner operating conditions. The new simulations confirm the previously observed overall system behavior and further demonstrate the influence of Reynolds number on the combustion process. Higher turbulence intensity leads to a broader ignition zone, enhanced oxygen entrainment, and increased ignition and conversion rates, while the particle-scale oxidation behavior remains largely unchanged, indicating weak coupling between gas-phase turbulence and individual particle combustion.