Accelerating CFD-DEM Simulation of Gas–solid Noncatalytic Reactions by a Novel Matrixized Implementation of the USCM Model

This study presents a novel matrix-based reformulation and an enhanced solving algorithm for the unreacted shrinking core model (USCM), designed for gas–solid noncatalytic reaction systems and demonstrated through the hematite reduction process. By reconstruction of the conventional reaction resistance network into a matrix form, the proposed approach not only simplifies the calculation of particle-scale reaction rates but also enables seamless integration into CFD-DEM simulations. Simulation results from existing experiments, evaluated using both the traditional method and the new matrix method, confirm that (i) the matrix method retains accuracy equivalent to that of the original approach; (ii) the method offers a systematic way to analyze reaction mechanisms via the resistance matrix, revealing through its main-diagonal dominance that hematite reduction is governed by interfacial chemical reactions; and (iii) the matrix-based solver significantly improves computational efficiency, achieving approximately 22% acceleration in a gas–solid fluidization case involving 1.5 billion real particles with a coarse-graining ratio of 10. This work underscores the advantages of matrixed USCM in both modeling flexibility and computational performance for large-scale particle systems.