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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Performance Improvement of PEM Fuel Cell with Enhanced Heat and Mass Transport by a Flow Pulsation

Get access (open in a dialog) DOI: 10.1615/IHTC15.kn.000030
pages 543-558

Abstract

The addition of oscillation effect into a laminar flow stream has been well documented to increase the effective heat and mass transport in the open literatures. The fuel cell system, especially a proton exchange membrane (PEM) fuel cell also consumes the hydrogen at the anode and the oxygen at the cathode to produce electricity in the laminar and humid condition, producing water at the cathode after the reaction. Hence, the proper water and fuel management is a key factor to operate the fuel cell stably and efficiently. In this study, assuming that the velocity profile, concentration profile and pressure gradient along the channel have sinusoidal motion, we investigate numerically the basic characteristics of pulsating flow and effective mass diffusivity with respect to the frequency and the amplitude as parameters. Sequentially, we experimentally observe the acceleration of the water removal along the channel and the enhancement of the oxygen diffusion rate through the gas diffusion layer caused by higher effective mass diffusivity, thereby improving the operation stability as well as the power performance. The polarization behavior shows the power enhancement up to 100% in an air breathing/cooling operation and the higher fuel utilization up to 98% in anodic dead end mode operation. Furthermore, we observe the higher power gain when examining a fuel cell stack rather than a single cell, implying that the pulsation solves the flow mal-distribution through a header inside a fuel cell stack. Finally, additional power gain, in other words, contribution of pulsation especially takes large portion in higher current loading region where the fuel cell experiences a large water production and heat generation.