Reduced Modelling of a Solid Oxide Fuel Cell for Design Applications

Abstract

Ongoing research has demonstrated that fuel cell technology is steadily progressing and has proven to be more reliable than other energy alternatives such solar, wind and renewable power. It is thus in our interest to expand on the knowledge of fuel cells to achieve the goal of greener and more efficient power generation in the near future.The objectives of this thesis are two-fold and carry on the previous work of Tseronis (2009). Firstly, the two-dimensional planar solid oxide fuel cell, developed by Tseronis (2009), is described by coupled mass, energy, and charge transport as well as by the Butler-Volmer equation at the triple phase boundaries. Particularly, mass transport is defined by Maxwell-Stefan equations in the gas channels and by the dusty gas model in the electrodes. In literature, it is more common to express mass transport in terms of Fick's diffusion equations as they are simpler and faster to implement; however, in theory the dusty gas model predicts the species interactions more accurately. The first objective is thus to construct an identical model to the one developed by Tseronis (2009) with the same model assumptions and design parameters and to replace the dusty gas model equations with Fick's diffusion equations. The two models are then compared in terms of pressure gradients, temperature profiles, charge distributions and average current density variations. A parametric study is also performed to determine how the models compare at different inlet boundary conditions and the corresponding step changes in parametric values.The next objective of this thesis is to reduce the complexity of the model developed by Tseronis (2009) by applying the method of proper orthogonal decomposition. Tseronis (2009) used this technique to reduce only the dusty gas equations of a two-dimensional anode; the next step is to continue the work by reducing the mass, energy and charge equations in the entire solid oxide fuel cell in order to obtain a computationally less intensive model that will be suitable for transient modelling. The resulting low order model can then be used for control applications once the boundaries have been incorporated into it. Model order reduction is performed on the main equations of the model proposed by Tseronis (2009) and therefore focuses only on the bulk of the system. The reduced and actual models are then compared in terms of temperature and pressure distributions. Additionally, a parametric study is performed whereby the inlet boundary conditions are altered in the original system and the actual and reduced models are compared.

Date of Award	1 Aug 2013
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Constantinos Theodoropoulos (Supervisor)