V. Lawlor

The use of a high temperature wind tunnel for MT-SOFC testing—Part I: detailed experimental temperature measurement of an MT-SOFC using an avant-garde high temperature wind tunnel and various measurement techniques

The purpose of the first part of this study was to compare four different temperature measuring methods. The application of these tools for possible temperature monitoring or calibration of monitors of microtubular solid oxide fuel cells (MT-SOFCs) is explored. It was found that a thermographic camera is very useful to visualize the temperature gradient on the outside of a cell, while an electrochemical impedance spectroscopy method was useful for estimating the core temperature of a test cell. A standard thermocouple was also used in combination with the previous two methods. Furthermore, an inexpensive laser guided thermometer was also tested for MT-SOFC temperature measurement. This initial study has opened up a range of questions not only about the effect of the experimental apparatus on the measurement results but also about the radial temperature distribution through a MT-SOFC in a working mode. Both these topics will be further investigated in part II of this study through a computational fluid dynamics study. This should provide additional interesting information about any differences between testing single cells and those within a bundle of cells. The discussed results are expected to be mainly temperature related, which should have direct consequences on power output and optimized gas inlet temperatures.

Experimental and Numerical Study of Various MT-SOFC Flow Manifold Techniques: Single MT-SOFC Analysis

Standard anode supported micro tubular-solid oxide fuel cell (MT-SOFC) stacks may provide the oxidant, in relation to the fuel, in three different manifold regimes. Firstly, “co-flow” involves oxidant outside the MT-SOFC flowing co-linearly in relation to the fuel inside. Secondly, “counter flow” involves oxidant outside the MT-SOFC flowing counter-linearly in relation to the fuel inside the MT-SOFC. Finally, “cross-flow” involves the oxidant outside the MT-SOFC flowing perpendicular to the fuel flow inside the MT-SOFC. In order to examine the effect of manifold technique on MT-SOFC performance, a combination of numerical simulation and experimental measurements was performed. Furthermore, the cathode current tap location, in relation to the fuel flow, was also studied. It was found that the oxidant manifold and the location of the cathode current collection point on the MT-SOFC tested and modeled had negligible effect on the MT-SOFC’s electrical and thermal performance. In this study, a single MT-SOFC was studied in order to establish the measurement technique and numerical simulation implementation as a prerequisite before further test involving a 7 cell MT-SOFC stack. [DOI: 10.1115/1.4023216]

Scrutiny of MT-SOFC Stack Manifolding Design Using CFD

In this work we investigated the use of Computational Fluid Dynamics (CFD) in order to describe the behav- iour of a single Micro Tubular Solid Oxide Fuel Cell (MT-SOFC) and a bundle thereof. It is the first step before building a rather necessarily complicated experimental apparatus in order to compare the predictions with experimental measure- ment. The first goal of this study was to test the suitability of commercially available CFD & SOFC modelling software, with some modified features. The second goal was to predict the effects of various fuel and oxidant manifolding tech- niques regarding temperature, species and current density distributions. A result of this paper showed that CFD is a very useful tool, when a SOFC module is incorporated for MT-SOFC stack modelling. A second result showed that the oxidant flow regime was much more important than the fuel regime in order to manipulate a single MT-SOFCs temperature pro- file. The cases investigated had a radiation model included and the differences in temperature profiles, when radiation was included and neglected, especially for MT-SOFCs with view factors to the reactor housing, was shown to be important. The CFD predictions clearly showed the benefits and advantages associated with the different forms of fuel and oxidant manifoldings. A future experimental analysis is currently being designed.