Effect of Inlet Flow Conditions on Flow Uniformity in a PEM Fuel Cell

The use of fuel cells as an alternative to traditional small scale power producing devices such as internal combustion engines or disposable batteries has continued to gain widespread acceptance. Flow maldistribution within cells in a stack continues to be an issue in fuel cell design and can adversely affect performance and longevity. Current research in this field has focused on effects of inlet configurations (plug flow versus circular inlet, for example) on the flow in a rectangular manifold and the resulting distribution into individual cells in the stack. In a typical small scale application, the piping which transports the reactant will contain bends in it. As these bends can introduce Dean vortices and flow asymmetries within the pipe flow, such conditions should be examined to determine whether they will affect the manifold flow and further impact cell maldistribution. A simplified scaled up model of a PEM fuel cell was fitted with different inlet flow configurations, including straight piping and piping containing a 90 degree bend prior to entering the manifold. Particle Image Velocimetry (PIV) was used to obtain mean and fluctuating velocity statistics within the manifold and in individual cells. These distributions will be compared with previous results obtained from this apparatus corresponding to a partially developed square inlet profile, as well as available experimental and computational data in the literature.