Modeling and experimental investigation of transport processes during the flow of viscous fluids in porous materials

This work demonstrates the influence of hydrodynamic interactions and microconvection on energy transport in multi-phase systems using experimental, modeling and numerical techniques. These techniques are applied to the non-affine motion (relative motion between the particles and the fluid) of sedimenting particles. Modeling and numerical techniques are then extended to creeping flow through ideal porous media. The experimental technique is used for the investigation of boundary layer flow which couples Darcy flow and an open flow through a permeable interface.;The first part of the work covers the experimental investigation of an ideal two phase flow which is represented by a sedimenting suspension of hard micro-spheres in quiescent Newtonian fluid. The results of these experiments performed using Laser Doppler Anemometry (LDA) indicated the presence of strong hydrodynamic interactions between the sedimenting particles even at low particle volume fractions. Using a unit cell model the enhanced heat transfer occurring in a sedimenting suspension due to non-affine motion of falling particles is investigated numerically. This approach, when extended to flow through ideal porous media, has shown the importance of micro-convection and its significant impact on thermal transport during the manufacture of typically thin advanced composites using Resin Transfer Molding (RTM).;The second part of the work is concerned with the experimental investigation of non-Darcy flow encountered in practical RTM situations. The decay of slip velocity at the permeable interface is generally modeled by using Brinkman's modification of Darcy's law. Using LDA, these profiles were measured experimentally for random as well as aligned fiber mats confined between flat walls of a planar mold of small depth in which Hele-Shaw approximation is valid. In each and every case, the boundary layer zone of the order of mold depth was observed which is much larger as compared to the Brinkman's prediction. Models are presented which predict boundary layer flow based on the fact that the thickness of the boundary layer is of the order of the mold depth for a thin mold. Excellent comparison with the experimental data is observed.