A numerical study and design of multiple jet impingement in a PEMFC
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Date
Authors
Lum, K.W.
Birgersson, E.
Ly, H.
Poh, H.J.
Mujumdar, A.S.
Journal Title
Journal ISSN
Volume Title
Publisher
International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics
Abstract
Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
Impinging jets are widely used in applications where high rates of heat and mass transfer are required. Similarly, an efficient operation of the Proton Exchange Membrane Fuel Cell (PEMFC) relies on high heat and mass transfer rates to and from the catalyst layers on the anode and cathode side, which raises the question of whether jet impingement could be employed for a PEMFC as well. To answer this question, a laminar non-isothermal gas-phase model for a PEMFC equipped with a porous flow field is solved numerically for five different cases: (i) single jet (cathode); (ii) double jet (cathode); (iii) triple jet (cathode); (iv) single jets (anode, cathode); (v) ordinary flow without jets. It is found that the jets reduce the size of the concentration boundary layers in the net at the flow field/gas diffusion layer interface (GDL), but do not penetrate significantly into the GDL for low permeabilies of around 10-12 m2. For macroporous layers with permeabilities of around 10-9 m2, the jets are able to penetrate deeply. For multiple jets, the risk of entrainment with oxygen depletion between jets is demonstrated, with a resulting loss in cell performance. Overall, this initial study indicates that jets can enhance cell performance, but care must be taken so as to avoid entrainment effects when employing multiple jets in a PEMFC.
Impinging jets are widely used in applications where high rates of heat and mass transfer are required. Similarly, an efficient operation of the Proton Exchange Membrane Fuel Cell (PEMFC) relies on high heat and mass transfer rates to and from the catalyst layers on the anode and cathode side, which raises the question of whether jet impingement could be employed for a PEMFC as well. To answer this question, a laminar non-isothermal gas-phase model for a PEMFC equipped with a porous flow field is solved numerically for five different cases: (i) single jet (cathode); (ii) double jet (cathode); (iii) triple jet (cathode); (iv) single jets (anode, cathode); (v) ordinary flow without jets. It is found that the jets reduce the size of the concentration boundary layers in the net at the flow field/gas diffusion layer interface (GDL), but do not penetrate significantly into the GDL for low permeabilies of around 10-12 m2. For macroporous layers with permeabilities of around 10-9 m2, the jets are able to penetrate deeply. For multiple jets, the risk of entrainment with oxygen depletion between jets is demonstrated, with a resulting loss in cell performance. Overall, this initial study indicates that jets can enhance cell performance, but care must be taken so as to avoid entrainment effects when employing multiple jets in a PEMFC.
Description
Keywords
Numerical study and design, Multiple jet impingements in a PEMFC, Proton exchange membrane fuel cell, Laminar non isothermal gas phase model, Porous flow field, Gas diffusion layer, GDL, Laminar, Jet impingement, Design, Mathematical modelling, Simulation, CFD
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Citation
Lum, KW, Birgersson, E, Ly, H, Poh, HJ & Mujumdar, AS 2008, A numerical study and design of multiple jet impingement in a PEMFC, Paper presented to the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July 2008.