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@PHDTHESIS{Rckert:961211,
      author       = {Rückert, Marcel},
      othercontributors = {Murrenhoff, Hubertus and Schmitz, Katharina},
      title        = {{R}eproducibility of falling body viscometry},
      volume       = {113},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Düren},
      publisher    = {Shaker Verlag},
      reportid     = {RWTH-2023-06683},
      isbn         = {978-3-8440-9077-2},
      series       = {Reihe Fluidtechnik / D},
      pages        = {1 Online-Ressource : Illustrationen, Diagramme},
      year         = {2023},
      note         = {Druckausgabe: 2023. - Auch veröffentlicht auf dem
                      Publikationsserver der RWTH Aachen University; Dissertation,
                      RWTH Aachen University, 2023},
      abstract     = {The need to increase efficiency is pushing the limits to
                      extreme conditions. Elevated loads by the increase of
                      operating pressure or speed as well as new materials enhance
                      the requirements on fluids as a design element. Viscosity,
                      as the primary factor influencing hydrostatic and dynamic
                      fluid properties, plays a decisive role. Particularly at
                      high operating pressures, viscosity can increase by several
                      orders of magnitude. It is therefore of great interest to be
                      able to determine the viscosity over the entire operational
                      range. In this work, the reproducibility of falling body
                      viscometry is investigated. For this purpose, a new
                      continuous measuring method for pressure ranges up to 8,000
                      bar is developed, which is able to identify stationary
                      falling conditions. In an analysis all influences acting on
                      the falling body are investigated and promising falling body
                      shapes are identified. With the aid of a numerical flow
                      simulation and coupled adjoint optimisation, a falling body
                      is developed for increased Stokes flow performance. By using
                      a ferritic, corrosion-resistant steel, an inductive velocity
                      detection over the complete measuring length as well as an
                      active lifting of the falling body is made possible. The
                      newly developed method is suitable for the automated
                      viscosity measurement of high- as well as low-viscosity
                      fluids and thus covers the range from bio-fuels to hydraulic
                      oil. Due to the innovative measuring principle, the velocity
                      of the falling body can be continuously recorded and thus
                      stationary conditions can be identified. By means of
                      analytical and numerical methods, it can be shown that a
                      falling body tends towards large eccentricities during the
                      fall in a tube, which significantly increases its fall
                      velocity. Furthermore, a variation of the falling body
                      geometry shows that the falling body shape has a significant
                      influence on the reproducibility of the measurements. The
                      adjoint optimised body provides very good reproducibility
                      and is suitable for the use with low-viscosity fluids. For
                      high viscosity fluids it can be shown that fins on the
                      lateral surface of the falling body have a small influence
                      on the flow and a concentric fall can be realised.},
      cin          = {412810},
      ddc          = {620},
      cid          = {$I:(DE-82)412810_20180620$},
      pnm          = {DFG project 39030946 - EXC 236: Maßgeschneiderte
                      Kraftstoffe aus Biomasse (39030946)},
      pid          = {G:(GEPRIS)39030946},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      doi          = {10.18154/RWTH-2023-06683},
      url          = {https://publications.rwth-aachen.de/record/961211},
}