Masters Theses
Date of Award
8-2006
Degree Type
Thesis
Degree Name
Master of Science
Major
Mechanical Engineering
Major Professor
R. V. Arimilli
Committee Members
M. Keyhani, J. C. Conklin
Abstract
Graphite foam, developed by the Oak Ridge National Laboratory, has shown excellent thermal properties and has potential applications for compact heat exchangers. The flow and heat transfer characteristics of a 2-D channel partially filled with graphite foam as the porous medium are determined. A steady, incompressible and constant-property water flow is modeled using the commercial software COMSOLâ. Flow is uniform at the inlet and the base of the foam is subjected to a constant heat flux boundary condition. The permeability( 7x10-8 to 1.4x10-6 m2)and the dimensionless height of the porous block are varied. Heat fluxes of 1x105 and 3x105 W/m2 are considered for Reynolds numbers of 1000 and 2000.
For the range of parameters considered in this study, the results show that
(1) The friction factor decreases with increase in Reynolds number and permeability. It increases almost exponentially at moderate to higher values of dimensionless block height.
(2) The Nusselt number increases with Reynolds number, permeability and dimensionless block height.
(3) The maximum surface temperature of the heater decreases with increasing Reynolds number and dimensionless block height. It decreases with increasing permeability for both Reynolds number and heat flux cases considered.
(4) A dimensionless parameter effectiveness is introduced and it increases linearly with heat flux and decreases rapidly with increase in Reynolds number. For example, when Reynolds numberis doubled effectiveness is shown to drop by a factor of about eight.
(5) For the two values of heat fluxes and for all permeability values considered in this study, the maximum effectiveness is found to occur at hp/H = 0.15 and 0.10 for ReDh=1000 and 2000, respectively.
Recommended Citation
Kuppa, Srinivas, "Flow and Heat Transfer in a 2-D Channel Partially Filled With Porous Medium. " Master's Thesis, University of Tennessee, 2006.
https://trace.tennessee.edu/utk_gradthes/1722