Effect of flow field design and channel/header ratio on velocity distribution: An experimental approach

In this paper, an investigation was carried out to observe the effect of flow field design on flow distribution uniformity and its effect on a fuel cell performance. The research followed two methodologies; the first examined the effect of several flow field plate designs (Single Serpentine, parallel Z, 2Z, U, and 2U) on distribution uniformity of flow velocity. The second methodology involved studying the effect of header/channel area ratio on flow velocity distribution in “Parallel Z and U- type” flow fields in an attempt to obtain a more uniform distribution of flow velocity. Results acquired from first research methodology showed that using the serpentine flow field design resulted in a very small non-uniformity coefficient of flow velocity distribution of nearly 0.0271 which indicates uniform flow velocity distribution with highest pressure drop, while the U-type yielded the highest non-uniformity coefficient (0.246-0.249) which represents non-uniform distribution of flow velocity with lowest pressure drop. The results obtained from the second research methodology while using a fixed header area and variable channel area for both parallel Z and U-type channels; showed a decrease in non-uniformity coefficient with decreasing header/channel area ratio with increasing overall pressure drop in both types of flow channel design.