rCFD-DEM modelling of the bi-dispersed dense particle-gas reacting flow in a bubbling fluidised bed: from spherical to non-spherical

• A novel Superquandric particle conduction model has been proposed. • The reactive smooth coarse-grained Superquandric CFD-DEM model has been developed for modelling dense non-spherical particle-gas reacting flows. • Non-spherical fuel particles with a lower sphericity tend to present a higher thermal-reactive performances. CFD-DEM modelling of dense non-spherical particle-gas reacting flow has been increasingly attractive, since non-spherical particles are widely applied in the practical thermochemical sectors. However, it is still challenging due to the lower computational efficiency of the conventional CFD-DEM method and the lack of more effective non-spherical particle heat-mass transfer submodels. In this study, our previously proposed smooth coarse-grained rCFD-DEM model has been fully extended from spherical to non-spherical for modelling dense non-spherical particle-gas reacting flow systems through proposing a novel non-spherical particle conduction model and incorporating the cutting-edge Superquadric particle method. The model has been comprehensively verified and validated by comparing the simulated results with the data from the experimental measurements. The model effectiveness verification proves that the proposed smooth CG-SQP-rCFD-DEM with a coarse-grained ratio of 2 not only shows the accurate numerical simulation results but also significantly reduces the computational costs by 93.58% under the given conditions. Then, the model has been applied to clarify how char particle shape impact on the in-reactor flow-thermal-reactive performances in a dense bi-dispersed non-spherical particle-gas bubbling fluidised bed (BFB) char combustor. Results indicate that the heat of reaction and radiation dominate the heat transfer process in the BFB char combustor, and non-spherical char particles with a lower sphericity tend to present a higher thermal and reactive performance. This work provides a cost-effective tool for understanding and optimising the dense non-spherical particle-gas reacting flow systems.