Graduation Semester and Year

2017

Language

English

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Daejong Kim

Abstract

Solid Oxide Fuel Cell (SOFC), is a clean and low-pollution technology of generating power of high efficiency. Its applicability for both stationery and transportation power generation systems, adaptability for wide range fuel sources, as wells its process of direct conversion of fuel to energy make it an important source of power generation. An effective design of sub-systems or individual components play a key role in overall working of a plant. Thus, critical analysis at the component level is of importance for the overall plant efficiency. In the present study a heat transfer model of a planar SOFC stack to be used as a component in a hybrid gas turbine power generation system is analyzed. The planar stack model is studied owing to its advantage in terms of high output power density, applicability for wide power generation systems, ease in component level design and manufacturing. The thesis presents a numerical heat transfer model in which a finite volume computational technique is used to solve the governing energy equation for fluid flow and heat transfer. Convection-diffusion equation is used to model the temperature variation for air and the fluid mixture. Heat conduction equation to model temperature variation through the metal structure. Thermodynamic species balance to model species variation in the mixture owing to steam reforming and water gas shift reaction occurring in the stack. Property variation for air and gas mixtures like specific heat, viscosity, conductivity, mixture concentration and reaction kinetics like Gibbs energy, reaction rate, rate constant, equilibrium constant are modelled as a function of temperature. Flow admittance form of the momentum equation is used to model momentum. The solver thus solves for the temperature for air, gas mixture, solid geometry, and the concentration of the species iteratively till all the values converge. The model can be easily integrated into a hybrid cycle called as “SOFC Gas-Turbine Hybrid System” or can be used as a stand-alone model to simulate the stack at component level.

Keywords

SOFC

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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