M7 Heat and Mass Transfer in Packed Beds with Fluid Flow
A complete description of heat and mass transfer in packed beds with fluid flow means computation of velocity, concentration, and temperature fields in three dimensions (3D) with full local resolution. For this purpose, the positions and surface contours of every particle in the bed must be precisely known. Subsequent computation of the flow field is not an easy task, and the computational demand increases if mass transfer has also to be considered. Most demanding is the consideration of heat transfer in coupled heat and mass transfer problems. Treating the thermal conductivity of packings with a stagnant fluid phase in Subchap. D6.3, we have pointed out that a dilemma exists between the number of particles that can be considered and the resolution that can be attained in regions with high heat fluxes, such as the regions around particle contact points. The same dilemma applies to flow and mass transfer.