Book/Dissertation / PhD Thesis

FZJ-2020-03251

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Water Management in Automotive Polymer-Electrolyte-Membrane Fuel Cell Stacks

Asanin, S. (Corresponding author)FZJ*

2020
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-491-1

Please use a persistent id in citations: http://hdl.handle.net/2128/25848  urn:nbn:de:0001-2020102017

Abstract: The detailed simulative investigation of the water management inside automotive PEM fuel cell stacks requires a three-dimensional multiphysics stack model. Due to the lack of appropriate literature approaches, which include the multiphase water transport, in addition to all fluid flow, thermal and electrochemical phenomena a suitable model is developed within the present study. The description is subdivided into two main paths i.e. water transport inside the gas channels of the flow field and within the layers of the MEA. In order to tackle the link between the two, a multi-scale approach is applied. The investigation levels are stack, single cell and single channel. A simplified cell model is derived by using a Darcy-like approach inside the flow fields with a drastic reduction in computational cells. In order to account for two-phase flow effects inside the gas channels, the capability of implementing two-phase pressure drop correlations is integrated. Correlations are obtained through two-phase flow Volume-of-Fluid simulations within single gas channels of anode and cathode respectively. Therefore, a methodology for adaptive mesh refinement (AMR) is derived to effectively investigate the phenomena of two-phase flow in gas channels. During the analysis, effects of dynamic and static contact angles are implemented and compared against each other, showing the necessity of dynamic contact angle models. A speed-up of the simulation process is achieved through a constant coarse mesh refinement (CCMR), using a high resolution interface capturing (HRIC) algorithm. The methodology is validated against detailed AMR results and used for parametric studies, regarding gas and liquid water input velocities. Hereby a study is carried out to investigate the dependency of number and position of liquid water inlet. The results show an independence regarding flow regime and stationary two-phase pressure drop values. Two-phase pressure drop correlations are derived from the filtered and processed result data. Experimental current density and temperature distribution results, as well as detailed simulations are used as a basis for the simplification process and the subsequent validation. The simplified cells are electrically and thermally connected within a 60-cell stack, automatically generated through a developed code. Stack simulations at various operating points are performed and validated against simulative simplified single cell and experimental 60-cell stack data. Very good prediction capabilities of the stack model, regarding stack performance are achieved.

Note: RWTH Aachen, Diss., 2020

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Contributing Institute(s):

1. Elektrochemische Verfahrenstechnik (IEK-14)

Research Program(s):

1. 135 - Fuel Cells (POF3-135) (POF3-135)

Appears in the scientific report 2020

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