Seeking minimum entropy production for a tree-like flow-field in a fuel cell

Area of Science:

• Energy Science
• Chemical Engineering
• Materials Science

Background:

• Polymer electrolyte fuel cells (PEFCs) rely on efficient reactant distribution for optimal performance.
• Traditional flow fields like serpentine and parallel designs can lead to uneven distribution and performance limitations.
• Tree-shaped flow fields offer potential for improved reactant delivery.

Purpose of the Study:

• To theoretically investigate a novel tree-shaped flow field with rectangular channels and T-shaped junctions for PEFCs.
• To compare the entropy production of this novel design against a Murray's law-based flow field.
• To analyze the impact of channel geometry parameters on flow dynamics and efficiency.

Main Methods:

• Development of a quasi-1D model for analyzing flow fields.
• 3D hydrodynamic calculations used as a reference for validation.
• Systematic variation of inlet channel width (w0) and width scaling parameter (a).
• Computation of Peclet number at channel outlets.

Main Results:

• The novel tree-shaped flow field exhibits lower entropy production than the Murray's law-based design.
• The quasi-1D model accurately predicts pressure drops and channel flows within a few percent for most geometries.
• Energy dissipation is shown to be lower with the proposed model compared to Murray's law.

Conclusions:

• The developed tree-shaped flow field offers a more efficient alternative for reactant distribution in PEFCs.
• The quasi-1D model provides a valuable tool for designing optimized flow fields.
• This research opens new avenues for designing fuel cells and catalytic systems with uniform fuel delivery.