Numerical Investigation of Iron Dust Oxidation in an Oxygen-Enriched Spherical Reactor

Iron dust has attracted growing interest as a recyclable, carbon-free energy carrier for high-temperature energy conversion systems. In this study, the combustion of micron-sized iron particles in an oxygen-enriched spherical reactor is numerically investigated using a coupled Eulerian-Lagrangian computational fluid dynamics (CFD) framework. The gas phase is modeled using the compressible Navier-Stokes equations with turbulence closure, while iron particles are tracked in a Lagrangian framework accounting for momentum, heat transfer, and heterogeneous oxidation. Iron combustion is represented by a simplified global surface reaction forming iron monoxide (FeO), which dominates at high temperatures. Simulations performed in a closed spherical reactor predict rapid ignition, peak gas temperatures of approximately 2500 K, and localized FeO formation governed by particle dispersion and oxygen availability. The results provide engineering insight into metal dust combustion behavior in confined systems.