Design of Elevated Temperature Bulk Particle Experiments for DEM Contact Model Parameter Calibration

Abstract

High-temperature granular systems are widely used in energy, mineral processing and chemical industries, where accurate prediction of particle behaviour is essential for process design and optimisation. The Discrete Element Method (DEM) is increasingly used to model such systems, however, its accuracy depends on the calibration of contact model parameters, which are commonly assumed to be temperature independent due to the scarcity of elevated-temperature contact property data. This work presents the development of an experimental and numerical framework for calibrating temperature-dependent DEM contact parameters using bauxite particles. A high-temperature test rig was developed to enable calibration experiments to be performed inside a chamber furnace whilst maintaining thermal equilibrium and external control of the experiment. Four calibration experiments were designed, comprising three bulk-particle experiments for indirect calibration, Angle of Repose, Rod Extraction and Plate Impact, together with one direct calibration experiment, Inclined Plane. Digital twin DEM models were developed and used to perform contact parameter sensitivity analyses. The suitability of the experiments for calibration was evaluated based on the sensitivity study results and used to develop a recursive four-stage calibration procedure to determine the temperature dependence of the DEM contact parameters. The methodology employs a multi-stage indirect calibration approach, in which parameters are calibrated individually or in pairs against experimental responses using DEM simulation generated sensitivity plots and response surfaces. The calibration procedure was demonstrated using Angle of Repose measurements obtained up to 1000 °C, from which the particle-particle coefficient of rolling friction was calibrated. The room temperature calibration result was validated against a previously published value using the same type of sintered bauxite particles, with close agreement shown. The study demonstrates the feasibility of adapting DEM calibration experiments for operation at elevated temperatures and establishes a practical framework for determining temperature dependent contact properties. The developed framework enables more accurate DEM modelling of high-temperature granular systems and provides a basis for future calibration studies across a wider range of particle materials and industrial applications.