The hydrogen and
fuel cell center
ZBT GmbH

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Dipl.-Ing. Jens Wartmann

Head of department

Micro Systems and Fluid Mechanics

phone: +49-203-7598-3336
j.wartmann@zbt-duisburg.de
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Flow field optimization

Application of CFD software for the simulation of gas flow in the gas distributions channels of flow field plates

The bipolar plate of a fuel cell has the triple function of electrically contacting the electrodes, connecting neighbouring cells and distributing the feed gases in the reaction zones. The optimal design of these gas feed and distribution channels, numerical simulations are necessary to meet the process requirements, which are often contrary to each other. E.g. a low pressure loss gives a low power consumption of peripheral equipment. To remove liquid product water from the gas channels and prevent the blockage of single or several channels, a high pressure loss over a flow field plate is helpful.

 Furthermore, the uniform distribution of the reaction gases has to be ensured, which intuitively requires a large channel-to-land ratio, whereas the electrical contact between flow field plate and electrode asks for the opposite.

Using Computer Aided Design (CAD), a model of a fuel cell or fuel cell stack is developed. The momentum, heat and species transport in the modell are then numerically calculated using Computational Fluid Dynamics (CFD). 

Fuel cell stack of five cells
Fuel cell stack of five cells
CAD Model of the gas dictribution channels
CAD Model of the gas dictribution channels
CFD simulation of the velocity distribution in the flow field of a bipolar plate
CFD simulation of the velocity distribution in the flow field of a bipolar plate

Different geometries are virtually tested instead of time- and money-consuming fabrication of prototype modells. Goal of these investigations are the analysis of the gas distribution, the derivation of design guide lines for flow fields, the optimization of the gas distribution and the reduction of the pressure loss.

The numerical implementation of the electrochemical processes then enables the prediction of the power and the current-voltage characteristics of the fuel cell.

Pressure loss of a 50cm<sup>2</sup> bipolar plate, cathode side: comparison of simulation, experiment and theoretical predictions
Pressure loss of a  50cm2 bipolar plate, cathode side: comparison of simulation, experiment and theoretical predictions
Current- voltage curve and power characteristics of a HTPEM fuel cell - Measurements (gray) and simulation results (black). [from C. Siegel et al. J. Power Sources 196, 2011, 2735-2749]
Current- voltage curve and power characteristics of a HTPEM fuel cell - Measurements (gray) and simulation results (black). [from C. Siegel et al. J. Power Sources 196, 2011, 2735-2749]

Available CFD software packages for flow simulations at ZBT

  • CFD-ACE+
  • Fluent
  • COMSOL Multiphysics

Examples for the application of flow field optimization techniques in projects of the ZBT:

Last update:  31.08.2016