Contents lists available at ScienceDirect Applied Thermal Engineering journal homepage: www.elsevier.com/locate/apthermeng Research Paper Heat transfer in PEM cooling flow field with high porosity metal foam insert Y. Vazifeshenas ⁎ , K. Sedighi, M. Shakeri Faculty of Mechanical Engineering, Babol Noushirvani University of Technology, Babol, Islamic Republic of Iran HIGHLIGHTS • Applying metal foam to coolant flow field channel increased the heat transfer. • Enhancing the porosity percentage decrease both heat transfer and pres- sure drop. • Improving the metal foam material could develop the heat transfer rate. • Water was superior than Ethylene- glycol in porous media usage. • The multichannel serpentine design revealed the best thermal behavior. GRAPHICAL ABSTRACT ARTICLE INFO Keywords: Metal foam Serpentine Cooling flow field Heat transfer PEM ABSTRACT Conventional cooling channel flow fields of Polymer Electrolyte Membrane Fuel Cells (PEMFCs) introduce some challenges that would reduce the cell total performance. So presenting novel ideas to improve the cooling flow fields is fully appreciable. The more common conventional flow fields include the serpentine, parallel and multichannel would be precisely studied in this paper. In order to see the effect of porous materials in heat transfer, metal foams were introduced to the channels. Unlike continuous long flow passages in conventional channels, metal foams provide randomly interrupted flow passages. Re-circulation of fluid, due to randomly distributed tortuous ligaments, enhances the heat transfer in these new channels. Moreover, to assess the fea- tures of utilizing metal foams in cooling channels, different parameters like metal type, porosity percentage and also the cooling media were investigated. Since both thermal and hydraulic points of view are important in cooling engineering, the heat transfer and pressure drop for all three channel types were verified. The results showed that enhancing the porosity of the metal foam would decrease both heat transfer and pressure drop. Also the multi-channel type revealed the best heat transfer behavior in presence of metal foams. 1. Introduction The global energy demand yielded to rapid use of fossil fuels which unfortunately raised several environmental concerns. In order to defeat the problems caused from greenhouse gases (GHG), fuel cell technolo- gies play an important role owing to zero emissions and high electrical efficiencies [1,2]. Particularly in the transportation use with large en- ergy consumption, fuel cells are sensible substitutions for batteries in terms of useful specific energy, storage space of the system, amount of GHG emissions and refueling time [3]. Fuel cell system can be com- mercialized when significant technical challenges are addressed; among them, the proper thermal management is the most critical issue which needs to be resolved [4–10]. Thermal protection is critical for PEM fuel cells and that is directly due to including exothermic reaction. Gen- erally, to prevent destruction of cells through thermal loading in a fuel cell stack, the temperature should be maintained uniform. Considering https://doi.org/10.1016/j.applthermaleng.2018.10.069 Received 24 July 2018; Received in revised form 9 October 2018; Accepted 17 October 2018 ⁎ Corresponding author. E-mail address: Joseph.vazifeshenas@gmail.com (Y. Vazifeshenas). Applied Thermal Engineering 147 (2019) 81–89 Available online 17 October 2018 1359-4311/ © 2018 Elsevier Ltd. All rights reserved. T