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COLLEGE OF SCIENCES
SCHOOL OF EARTH AND ATMOSPHERIC SCIENCES
EAS Ph.D. Defense
Hamid Karani
October 27, 2017
10:00 AM
Earth and Atmospheric Sciences
Ford Environmental Science & Technology (ES&T)311 Ferst Drive, ES&TAtlanta, GA 30332-0340Web: eas.gatech.edu
ES&T
1177
Title: A Multiscale Analysis of Heat Transfer in Porous Media
Committee members: Dr. Huber, Dr. Dufek, Dr. Simon,Dr. Ferrier, Dr.Magin(External committee member from U. Illinois at Chicago)
Abstract: The modeling of thermal convection in porous media is a challenging task due to the inherent structural and thermophysicalheterogeneities that permeate over several scales. In the present thesis, we address several issues relevant to buoyancy
driven thermal convection in porous media. Our approach is based on establishing
a multi-scale framework build on knowledge accrued by theoretical, numerical and
experimental methods.
In Chapter 2, we develop a pore-scale computational tool based on a lattice Boltzmann(LB) model. This computational tool enables us to tackle thermal convection
from a pore-scale perspective and to provide benchmarks for the development of an
appropriate continuum-scale models. In Chapter 3, we use our LB model and conduct
high-resolution direct numerical simulation at the pore scale. The objective is to evaluate the underlying assumptions of upscaledthermal models and to assess the role of
thermophysicalheterogenetieson heat transfer. We benefit from the insights gained
from our pore-scale results and propose a new upscaledenergy model for thermal
convection in Chapter 4. The proposed model is based on a fractional-order advectiveterm, which models the influence of thermal heterogeneities in a flexible and
consistent way. In Chapter 5, we used a combination of theoretical and experimental
approaches to calculate a new metric, basin stability, for quantifying the respective
relative stability of coexisting convection modes in porous media. We show that transition between convective modes predicted by the basin stability analysis agrees well
with the experiments from our IR thermography visualization setup.
