Title:
Radiative and transient thermal modeling of solid oxide fuel cells

Simple item page
dc.contributor.advisor Fedorov, Andrei G.
dc.contributor.author Damm, David L. en_US
dc.contributor.committeeMember Qu, Jianmin
dc.contributor.committeeMember Graham, Samuel
dc.contributor.department Mechanical Engineering en_US
dc.date.accessioned 2006-01-18T22:27:22Z
dc.date.available 2006-01-18T22:27:22Z
dc.date.issued 2005-12-02 en_US
dc.description.abstract Thermo-mechanical failure of components in planar-type solid oxide fuel cells (SOFCs) is a major obstacle on the path to bringing this technology to commercial viability. The probability of material degradation and failure in SOFCs depends strongly on the local temperature gradients at the interfaces of different materials. Therefore, it is of paramount importance to accurately predict and manage the temperature fields within the stack, especially near the interfaces. In this work we consider three effects in detail. First, we analyze radiative heat transfer effects within the semi-transparent solid electrolyte and compared them to thermal conduction. We also, present the modeling approach for calculation of surface-to-surface exchange within the flow channels and from the stack to the environment. The simplifying assumptions are identified and their carefully justified range of applicability to the problem at hand is established. This allows thermal radiation effects to be properly included in overall thermal modeling efforts with the minimum computational expense requirement. Second, we developed a series of reduced-order models for the transient heating and cooling of a cell, leading to a framework for optimization of these processes. The optimal design is one that minimizes heating time while maintaining thermal gradients below an allowable threshold. To this end, we formulated reduced order models (validated by rigorous CFD simulations) that yield simple algebraic design rules for predicting maximum thermal gradients and heating time requirements. Several governing dimensionless parameters and time scales were identified that shed light on the essential physics of the process. Finally, an analysis was performed to assess the degree of local thermal non-equilibrium (LTNE) within porous SOFC electrodes, and through a simple scaling analysis we discovered the parameter that gives an estimate of the magnitude of LTNE effects. We conclude that because of efficient heat transfer between the solid and gas in the microscale pores of the electrodes, the temperature difference between gas and solid is often negligible. However, if local variations in current density are significant, the LTNE effects may become significant and should be considered. en_US
dc.description.degree M.S. en_US
dc.format.extent 677383 bytes
dc.format.mimetype application/pdf
dc.identifier.uri http://hdl.handle.net/1853/7595
dc.language.iso en_US
dc.publisher Georgia Institute of Technology en_US
dc.subject Local thermal non-equilibrium en_US
dc.subject Porous media
dc.subject Transient thermal analysis
dc.subject Radiation heat transfer
dc.subject Thermal modeling
dc.subject Solid oxide fuel cells
dc.title Radiative and transient thermal modeling of solid oxide fuel cells en_US
dc.type Text
dc.type.genre Thesis
dspace.entity.type Publication
local.contributor.advisor Fedorov, Andrei G.
local.contributor.corporatename George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 22ed9217-97e1-449b-a93c-6caf41cd08d7
relation.isOrgUnitOfPublication c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
damm_david_l_200512_mast.pdf
Size:
661.51 KB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Theses and Dissertations