An Application of MRI to Measure Flow Distribution in Fuel Cell Channels

Abstract

This paper presents an application of MRI to measure flow distribution in fuel cell channels. Solid Oxide Fuel Cells (SOFC) are able to efficiently produce electricity directly from the oxidation of the natural gas by electrochemical conversion. The distribution of fuel gas between the high numbers of parallel flow paths within the fuel cell assembly is critically important to ensure high efficiency and uniform conditions within the fuel cell assembly. Practical approaches in conjunction with numerical models are needed to understand and control the physical processes taking place within fuel cells in order to design them to be efficient and reliable. The paper outlines a non-invasive experiment using magnetic resonance imaging (MRI) to measure the distribution of flow within an SOFC subassembly. The method quantifies the flow distribution by modelling the gas using water at Reynolds similar conditions. Water has a magnetic moment that can be imaged using an MRI scanner. Two-dimensional cross-section scans were taken perpendicular to the direction of flow in the fuel cell channel to measure area and velocity. The study evaluated a range of image resolutions and outlined how the data was processed to provide mass flow rates in each channel using the known fluid properties. At the highest image resolution the total mass flow rate was within 1% of the independent measurement from the experimental rig. The distribution of flow between the channels showed a similar trend to the computational model. The initial results demonstrate the feasibility for the method to measure flow in the SOFC channels.