Rigid spherical particles in highly turbulent Taylor-Couette flow

ORAL

Abstract

Many industrial and maritime processes are subject to enormous frictional losses. Reducing these losses even slightly will already lead to large financial and environmental benefits. The understanding of the underlying physical mechanism of frictional drag reduction is still limited, for example, in bubbly drag reduction there is an ongoing debate whether deformability and bubble size are the key parameters. In this experimental study we report high precision torque measurements using rigid non-deformable spherical particles in highly turbulent Taylor-Couette flow with Reynolds numbers up to $2 \times 10^6$. The particles are made of polystyrene with an average density of 1.036 g cm$^{-3}$ and three different diameters: 8mm, 4mm, and 1.5mm. Particle volume fractions of up to 6\% were used. By varying the particle diameter, density ratio of the particles and the working fluid, and volume fraction of the particles, the effect on the torque is compared to the single phase case. These systematic measurements show that adding rigid spherical particles only results in very minor drag reduction.

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Authors

  • Dennis Bakhuis

    Physics of Fluids Group, Mesa+ Institute and J.M. Burgers Centre for Fluid Dynamics, University of Twente, The Netherlands

  • Ruben Verschoof

    Physics of Fluids Group, Mesa+ Institute and J.M. Burgers Centre for Fluid Dynamics, University of Twente, The Netherlands, Physics of Fluids, MESA+ institute, University of Twente, the Netherlands

  • Varghese Mathai

    Physics of Fluids Group, Mesa+ Institute and J.M. Burgers Centre for Fluid Dynamics, University of Twente, The Netherlands

  • Sander G. Huisman

    Univ Lyon, Ens de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique, F-69342 Lyon, France, Physics of Fluids Group, Mesa+ Institute and J.M. Burgers Centre for Fluid Dynamics, University of Twente, The Netherlands

  • Detlef Lohse

    University of Twente, Physic of Fluids Group, University of Twente, Physics of Fluids Group, Mesa+ Institute and J.M. Burgers Centre for Fluid Dynamics, University of Twente, The Netherlands, Physics of Fluids, MESA+ institute, University of Twente, the Netherlands, Physics of Fluids Group, University of Twente, The Netherlands, Physics of Fluids group, Faculty of Science and Technology, University of Twente, The Netherlands, Physics of Fluids, Faculty of Science \& Technology, University of Twente, The Netherlands, Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Center for Fluid Dynamics and MESA+ Institute, University of Twente, Physics of Fluids Group, University of Twente, The Netherlands., Physics of Fluids Group, University of Twente, Physics of Fluids, University of Twente

  • Chao Sun

    Center for combustion energy, Tsinghua University, Beijing, China