The use of liquid fuel in the direct methanol fuel cell makes it very convenience for the different
applications especially the portable ones. The flow field is one of the key factors that affect the
fuel cell performance. It works on the supply of the reactant to the catalyst layers uniformly and
fast expel of the products from these reaction sites and away from the reactant path. In addition,
it collects the current produced from the reactions and transfer it to the external circuits. These
functions should be done with the minimum possible effort. It is realised that the nature can
deliver the water, food, nutrients along large distance with the minimal effort. Accordingly,
recent researches inspired different flow field configurations from the nature such as that
inspired from the plant leaf and human lunges. The DMFC performance is investigated using
leaf and lung based bio-inspired flow fields and compared with the cell performance using the
conventional serpentine and interdigitated flow fields. Furthermore, the bio-inspired flow field
is designed based on the Murry’s law. To achieve these goals, a three-dimensional single phase
model is used. The results shown that the bio-inspired flow fields increase the maximum
obtained power density by about 35% from that obtained by the conventional serpentine flow
field, while their performances are closer to the interdigitated one. Moreover, the use of
Murray’s law in the flow field sizing has minimal effect on both the total pressure losses and
cell performance. However, the total pressure losses associated with the bio-inspired flow fields
are smaller than both the interdigitated and serpentine flow fields