Numerical prediction of humidification process in planar porous membrane humidifier of a PEM fuel cell system to evaluat
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Numerical prediction of humidification process in planar porous membrane humidifier of a PEM fuel cell system to evaluate the effects of operating and geometrical parameters Seyed Zeynolaabedin Hashemi‑Valikboni1 · Seyed Soheil Mousavi Ajarostaghi1,2 · Mojtaba Aghajani Delavar1 · Kurosh Sedighi1 Received: 26 February 2020 / Accepted: 7 July 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract In present study, a numerical model is employed to investigate the effects of different operating parameters and channel geometry on the performance of membrane humidifier. Simulations are performed by a commercial CFD code and based on user defined functions. Three-dimensional counter-flow humidifier model for a gas-to-gas case is considered. Results show that an increase in porosity or permeability leads to better humidification. Moreover, increase in inlet temperature of dry and wet channels as well as inlet mass flowrate of water vapor would enhance humidifying process. On the other hand, by reduction in inlet mass flowrate of gas channel and thickness of the porous medium in membrane, better humidifier performance would be achieved. To investigate the geometric parameters, three different channel types including stepped, sinusoidal and zigzag are considered. It is found that stepped geometry has the best performance in humidifying. Keywords Porous media · Proton exchange membrane fuel cell (PEMFC) · Planar membrane humidifier · Heat and mass transfer · Numerical simulation List of symbols a Water vapor activity C Total concentration of species i D Diffusivity D0 Diffusivity at standard condition P Pressure (Pa) Su Source term of momentum equation T Temperature (K) u Mixture velocity (m s−1) * Seyed Soheil Mousavi Ajarostaghi [email protected] Seyed Zeynolaabedin Hashemi‑Valikboni [email protected] Mojtaba Aghajani Delavar [email protected] Kurosh Sedighi [email protected] 1
Department of Mechanical Engineering, Babol Noshirvani University of Technology, P.O. Box 484, Babol, Islamic Republic of Iran
Department of Mechanical Engineering, Université de Sherbrooke, 2500 Boulevard de l’Université, Sherbrooke, QC J1K 2R1, Canada
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Wm,dry Membrane dry equivalent mass ρm,dry Membrane dry density (kg m−3) Greek symbols ε Porosity in porous media λ Membrane water content μ Mixture viscosity (kg m−1 s−1) ρ Mixture density (kg m−3) κ Permeability (m2) Subscript and superscript i Species i of fluids M Membrane eff Effective properties W Wet side
Introduction Fuel cell systems have been utilized as power sources for various applications including vehicular propulsion, stationary power plants in buildings and residences, etc. [1]. A serious condition of PEM fuel cells is to keep sufficient water content in membrane electrolyte to guarantee required proton conductivity [2]. Generally, the humidified gas and
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oxidant are flowed to the anode and the cathode compartments to make the membrane fully hydrated in a vast current range [3]. Humidifier is used f
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