A discrete element approach to model packed bed thermal storage

Abstract

A discrete 1-D Eulerian and 3-D Lagrangian model was developed to analyze heat transfer in packed bedscomposed of spherical particles to study a in more detail the solid phase phenomenon. The proposed thermalmodel simulates the particles using the discrete element method, generating a particle distribution inside thepacked bed. It considers direct and indirect conduction, convection, and radiation and evaluates the local heattransfer phenomena. One of its main advantages is its flexibility to deliver results at the particle level, whichprovides detailed information than continuous models. A comparison with experimental data from the literatureindicates good agreement, with mean absolute errors lower than 8 K. Finally, through a sensitivity analysis, itwas demonstrated that the selection of an appropriate Nusselt number is essential because it is related to theconvective heat transfer, which corresponds to 85.8% of the total heat transfer during the charging process.For the standby process, particle fluid conduction is the predominant heat transfer mechanism, accounting for27.5% of the total heat transfer.