Impact of channel geometry on two-phase flow in fuel cell microchannels

Julie E. Steinbrenner, Eon Soo Lee, Carlos H. Hidrovo, John K. Eaton, Kenneth E. Goodson

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

An important function of the gas delivery channels in PEM fuel cells is the evacuation of water at the cathode. The resulting two-phase flow impedes reactant transport and causes parasitic losses. There is a need for research on two-phase flow in channels in which the phase fraction varies along the flow direction as in operating fuel cells. This work studies two-phase flow in 60 cm long channels with distributed water injection through a porous GDL wall to examine the physics of flows relevant to fuel cells. Flow regime maps based on local gas and liquid flow rates are constructed for experimental conditions corresponding to current densities between 0.5 and 2 A cm-2 and stoichiometric coefficients from 1 to 4. Flow structures transition along the length of the channel. Stratified flow occurs at high liquid flow rates, while intermittent slug flow occurs at low liquid flow rates. The prevalence of stratified flow in these serpentine channels is discussed in relation to water removal mechanisms in the cathode channels of PEM fuel cells. Corners facilitate formation of liquid films in the channel, but may reduce the water-evacuation capability. This analysis informs design guidelines for gas delivery microchannels for fuel cells.

Original languageEnglish (US)
Pages (from-to)5012-5020
Number of pages9
JournalJournal of Power Sources
Volume196
Issue number11
DOIs
StatePublished - Jun 1 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

Keywords

  • Ex situ
  • Flooding
  • Microchannels
  • PEM fuel cell
  • Two-phase flow

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