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Using Numerical Simulation in the Design and Analysis of Spiral PEM Fuel Cells

Arian Nazar, Mohammad Sadegh | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48625 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Kazem Zadeh Hannani, Siamak; Taghizadeh Manzari, Mehrdad; Roshandel, Ramin
  7. Abstract:
  8. The gas flow field geometry influences the transport phenomena inside PEMFCs and hence affecting their overall performance. Radial force and secondary flows resulting from curvature of the spiral channels in PEMFCs can improve mass transport limits and so does to their overall performance. Studying the effects of curvature of spiral channels on fuel cell performance and comparing them with similar designs is the aim of this thesis. The geometries are generated using concentric Archimedes’ spirals and categorized as axial or radial depending on the direction of the vector perpendicular to their MEA . Each category has five geometries which are the result of branching the main channel into 1,2,3,4 and 5 channels while keeping the total length of channels constant and equal to 30 cm. The computational grids are generated using GAMBIT and then prepared for two simulations (A and B) with different cathode channel’s Reynolds number using ANSYS FLUENT v.15 and polarization curves are drawn for each geometry with data of six different operating voltages. The results of simulation A, which the Reynolds number of the main feeding branch of the cathode channels is 1500, show that radial geometries perform generally better than axial counterparts. Setting the Reynolds number of the cathode channel in each branch equal to 1500 for simulation B, the results show that axial geometries perform slightly better than radial counterparts. Species distribution over the catalyst layers for simulation (A) show non uniformities. Although species distribution over the catalyst layers are more uniform for simulation (B), but a few percent of Oxygen and Hydrogen leaves the channels unused. Radial geometries also produce less pressure drop compared to their axial counterparts in both simulations
  9. Keywords:
  10. Numerical Simulation ; Polymer Electrolyte Membrane (PEM) ; Polarization Curve ; ANSYS Software ; Gas Flow Field Geometry ; Archimedes's Spirals ; GAMBIT Software

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