Particle Image Velocimetry
Measurements in a Model PEMFC
Particle image velocimetry was used to measure 2D
velocity fields in
representative regions of interest within flow channels of
interdigitated and single-serpentine PEM fuel cell models.
model dimensions, GDL permeability, working fluid, and flow rates were
selected to be geometrically and dynamically similar to the
cathode-side airflow in a typical PEM fuel cell.
The model was easily reconfigurable between parallel, single-serpentine
and interdigitated flow fields, and was constructed from transparent
materials to enable optical imaging. The use of rubber plugs
allowed easy change from one flow field design to the next.
Dimensional similarity was used to design a geometrically and
dynamically scaled fuel cell model. The flow conditions in
model were selected to match the cathode-side airflow in an equivalent,
albeit non-reacting fuel cell. Despite this limitation, the
allows several advantages which make it overwhelmingly simpler to
perform PIV measurements than in an operational fuel cell.
the walls of the model are transparent which has made it possible to
measure channel convective bypass for the first time.
maps were obtained of both the primary and secondary flow within the
channels. Measurements of the secondary flows in
and single-serpentine flow fields indicate that significant portions of
the flow travel between adjacent channels through the porous
medium. Such convective bypass can enhance fuel cell
by supplying fresh reactant to the lands regions, and also by driving
out product water from under the lands to the flow channels.