An ex-situ experiment to study the two-phase flow induced by water condensation into the channels of proton exchange membrane fuel cells (PEMFC)

2015 ◽  
Vol 40 (22) ◽  
pp. 7192-7203 ◽  
Author(s):  
Vincent Coeuriot ◽  
Jérôme Dillet ◽  
Gaël Maranzana ◽  
Olivier Lottin ◽  
Sophie Didierjean
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Two Phase Flow ◽  
Proton Exchange ◽  
Ex Situ ◽  
Phase Flow ◽  
Two Phase ◽  
Water Condensation ◽  
Exchange Membrane

Ex-Situ Characterization of Two-Phase Flow Regimes in Proton-Exchange Membrane Fuel Cells Under Non-Isothermal Conditions

2010 ◽  
Author(s):  
Arganthae¨l Berson ◽  
Jon G. Pharoah
Keyword(s):  
Proton Exchange Membrane ◽  
Two Phase Flow ◽  
Metal Foam ◽  
Flow Regimes ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Ex Situ ◽  
Phase Flow ◽  
Two Phase ◽  
Exchange Membrane

Efficient water management is crucial for the good performances of proton-exchange membrane fuel cells (PEMFCs). The geometric and physical characteristics of the components of a PEMFC as well as operating conditions have an impact on the transport of water through the porous transport layer (PTL) and the two-phase flow regimes in the microchannels. One parameter of importance is the local temperature, which affects properties such as surface tension and is coupled with phase change. Indeed, a temperature difference of about 5K is expected across the PTL, with spatial variations due to the geometry of the flow field plate. We present preliminary results obtained with a first experimental setup for the ex-situ characterization of two-phase flow regimes in the flow channels. Water is pushed through the PTL, which is sandwiched between a porous metal foam and the flow field plate. The air flow rate, temperature and humidity can be controlled. The cell can be heated up by applying an electrical current through the metal foam. A transparent window is located on top of the flow channel. The two-phase flow within the micro-channels is visualized using a high-speed camera and laser-induced fluorescence. Preliminary results obtained under isothermal conditions at room temperature show that different two-phase flow regimes occur in the channels depending on the operating conditions, in good qualitative agreement with data from the literature. Eventually, a new visualization cell is presented that is expected to correct the flaws of the previous design and will allow a better thermal control. It will be possible to adjust the temperature gradient and the mean temperature in order to observe their impact on two-phase flow regimes for different types of PTL and flow rates. The results will provide a better understanding of water transport in PEMFC and benchmark data for the validation of numerical models.

An Analysis of Two-Phase Flow Pressure Drop in Operating Proton Exchange Membrane Fuel Cell Channels With the Lockhart-Martinelli Approach

2014 ◽  
Author(s):  
Ryan Anderson ◽  
Lifeng Zhang ◽  
David P. Wilkinson
Keyword(s):  
Fuel Cells ◽  
Pressure Drop ◽  
Proton Exchange Membrane ◽  
Two Phase Flow ◽  
Proton Exchange ◽  
Phase Flow ◽  
Two Phase ◽  
Current Densities ◽  
Flow Pressure ◽  
Exchange Membrane

Proton exchange membrane fuel cells (PEMFCs) are considered one of the most promising alternatives for the automotive industry owing to their high energy efficiency, zero emission at the vehicle use stage, and low temperature operation. Water as a byproduct plays a complex role in fuel cell operation. In particular, the inevitable occurrence of liquid water leads to gas-liquid two-phase flows in various components of PEMFCs including flow channels of which diameters range from micrometers to millimeters. In conventional minichannels and microchannels, the Lockhart-Martinelli (LM) approach has been employed to predict the two-phase pressure drop of gas-liquid systems. This approach has previously been updated by our group to more accurately reflect the introduction of liquid water into the flow channels of a PEMFC i.e. from a porous media perpendicular to the gas flow. Importantly, the LM method normalizes the data independent of the flow field design and operating conditions like temperature, pressure, and relative humidity. This paper analyzes the increasing amount of experimental data on two-phase flow pressure drops/two-phase flow multipliers in the literature with these approaches. The focus is the cathode side (therefore an air/water system), and data is collected from multiple research groups using active fuel cells (electrochemically produced water). The traditional LM approach greatly under-predicts the two-phase pressure drop at low current densities. However, the analysis is applied over a range of current densities, and it better predicts results at higher current densities (>600 mA cm−2). Literature correlations for the Chisholm parameter C, a flow regime dependent parameter in the LM equation, have been proposed for non-active (external water injection) fuel cells but do not match the results from operating fuel cells. C is shown here to vary with current density, flow stoichiometry (gas velocity), gas diffusion layer, and slightly with relative humidity.

A critical review of two-phase flow in gas flow channels of proton exchange membrane fuel cells

2010 ◽  
Vol 195 (15) ◽  
pp. 4531-4553 ◽  
Author(s):  
Ryan Anderson ◽  
Lifeng Zhang ◽  
Yulong Ding ◽  
Mauricio Blanco ◽  
Xiaotao Bi ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Critical Review ◽  
Gas Flow ◽  
Proton Exchange Membrane ◽  
Two Phase Flow ◽  
Proton Exchange ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Channels ◽  
Exchange Membrane
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