Dominique Toye

Influence of back mixing on the convective drying of residual sludges in a fixed bed

The influence of a backmixing operation on the convective belt drying of two wastewater sludges was studied. The expansion of the sludge extrudates bed due to increasing additions of dry product was quantified by using X-ray tomography. This non-invasive technique was used to determine the bed porosity and the total exchange area available for heat and mass transfers, for increasing levels of backmixing. For a same drying flux, the expansion of the drying bed leads to higher drying rates, allowing a reduction of the total drying time. In this context, rheological properties of the sludges are key properties.

Lattice Boltzmann 3D flow simulations on a metallic foam

In this paper a lattice Boltzmann method (LBM) is used to simulate isothermal incompressible flow in a RCM-NCX-1116 metallic foam. The computational technique is a multiple relaxation time (MRT) lattice Boltzmann equation model. Computer aided X-ray micro-tomography is used to obtain 3D images of the metallic foam, providing the geometry and information required for LB simulations of a single phase flow. Pressure drops are computed and successfully compared to experimental measures and correlated with Erguns equation. Invariance of Erguns parameters A and B with the sampling rate of the images is observed.