Time-extrapolation of CFD-DEM Simulations for Iron Ore Reduction

Description

Applying DEM or CFD-DEM models to industrial-scale systems such as blast furnaces or direct reduction shaft furnaces unveils the immense numerical costs of these simulation methods. To reduce the required computational resources it is inevitable to decrease the level of detail of the applied method.
One possible strategy is the usage of a coarse-grain (CG) approach for the discrete phase, lowering the computational demand by using coarser (pseudo) particles. However, this approach may fail to capture effects that inherently depend on particle size. To alleviate these deficiencies, we have proposed a multi-level coarse-grain (MLCG) model. In this model multiple concurrently simulated coarse-grain levels are coupled to adjust the resolution of the system as needed. The MLCG model can also be applied to fluid-particle systems using CFD-DEM. This procedure allows us to cover the typical spatial scales of industrial plants.
To fully picture industrial processes involving the reduction of iron ore, however, we also need to be able to run our simulations for the full process time. While the chemical reduction of the material takes several hours to complete, even a coarse-grained CFD-DEM simulation is limited by a time step in the range of microseconds since particle contacts need to be resolved. To close this gap, we apply (flow-based) recurrence CFD (rCFD) as time extrapolation method, where particles are transported on precomputed recurrent flow fields and particle contacts no longer need to be resolved. The applicability of this model set is demonstrated by the reduction of iron ore pellets at elevated temperatures in a direct reduction shaft.

Period	23 Sept 2025
Event title	International Congress on Particle Technology (PARTEC 2025)
Event type	Conference
Location	Nürnberg, GermanyShow on map
Degree of Recognition	International