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@PHDTHESIS{Borah:894583,
      author       = {Borah, Deepjyoti},
      title        = {{T}wo-phase {F}low in {P}orous {T}ransport {L}ayers of
                      {P}olymer {E}lectrolyte {M}embrane {E}lectrolysers},
      volume       = {546},
      school       = {RWTH Aachen},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2021-03290},
      isbn         = {978-3-95806-564-2},
      series       = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {xi, 196 S.},
      year         = {2021},
      note         = {RWTH Aachen, Diss., 2021},
      abstract     = {Polymer electrolyte membrane (PEM) water electrolysis is an
                      important technology for the electrochemical splitting of
                      water. Inside PEM electrolysers, the porous transportlayers
                      (PTL) facilitate mass-transport and electric conduction. An
                      understanding of the gas-water flow inside the PTL is a
                      prerequisite to improving cell performance. To the best of
                      the author’s knowledge, experimentally measured relative
                      permeability of PEM electrolyser PTLs has not yet been
                      published in literature. This thesis aims to achieve this
                      through experiments and to validate results from
                      simulations. For experimental characterisation, six
                      different PTLs were chosen, and similar techniques for
                      measurements of geological samples were considered. However,
                      their microscale size presents unique challenges in applying
                      these techniques directly. Hence, a new test cell was
                      developed, and both absolute, and relative permeability were
                      determined. Computer tomography (CT) images were taken for
                      all six samples to generate 3D-models of the porous PTL
                      structures. The flow simulations were performed using four
                      different tools: pore network model (OpenPNM), voxel-based
                      computation (GeoDict), conventional computational fluid
                      dynamics (ANSYS Fluent), and Lattice Boltzmann method
                      (Palabos). Two-phase flow simulations were performed only
                      with OpenPNM and ANSYS Fluent. Out of the four methods,
                      GeoDict and Palabos required the minimum amount of
                      preprocessing. Pore network method was the least
                      computationally expensive method. ANSYS Fluent required the
                      most amount of preprocessing and computation time.
                      Three-dimensional meshes were created using different
                      open-source and proprietary tools, but only a relatively
                      small portion of the image stack could be used due to
                      computational limitations. GeoDict and Palabos produced
                      nearly identical results. Except for ANSYS Fluent, all the
                      other tools computed through-plane permeability values close
                      to experimental values. The simulations did not match the
                      experimental in-plane permeability values. Relative
                      permeability was computed from pore network simulations.
                      Computed air relative permeability curves and the respective
                      measurements agreed. The water relative permeability curves
                      did not match experiments, although both were very small in
                      magnitude. It is observed that relative permeability
                      saturation correlations used in literature are not
                      experimentally validated. This work produced experimental
                      relative permeability curves for sintered titanium porous
                      transport layers of PEM electrolyser systems for the first
                      time.},
      cin          = {IEK-14},
      cid          = {I:(DE-Juel1)IEK-14-20191129},
      pnm          = {899 - ohne Topic (POF4-899)},
      pid          = {G:(DE-HGF)POF4-899},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:0001-2021093016},
      url          = {https://juser.fz-juelich.de/record/894583},
}