Unresolved FEM-DEM model for heated immersed granular flows

  • Henry, Michel (iMMC)
  • Dorbolo, Stéphane (CESAM-GRASP)
  • Lambrechts, Jonathan (iMMC)
  • Legat, Vincent (iMMC)

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Recently, it has been observed that water droplets deposited gently on a hot granular bed tend to dig into this bed. Chimneys are created in the wake of the droplet by the generation of steam which ejects the surrounding particles. The depth reached by the droplet can be up to 10 times their diameter. In this presentation, we propose an unresolved FEM-DEM model to solve the conservation of momentum and energy in the mixture, using well-chosen correlations for the specific application. We will discuss the relevance of this model for thermal particle flows and highlight the similarities between momentum and heat transfer. A suspension is a mixture of small particles immersed in a fluid solvent, and its rheological properties depend on both the particle scale and the flow scale. To capture local interactions, the Discrete Element Method is used to describe the particles which incorporates the non-contact dynamics to prohibit any interpenetration during collisions. The fluid is represented using the Averaged Navier-Stokes equations, solved with the Finite Element Method. The coupling between the two scales is achieved through momentum and heat transfer correlations. Our work proposes a weakly coupled model to solve thermal particle flows, incorporating a new correlation to characterised the heat transfer of particle in a granular bed. This model is used to study the excavation of the hot granular bed and provides local insight into particle motion and temperature evolution.