NORDIC PULP & PAPER RESEARCH JOURNAL
Home » Volume 32, 2017 » Issue No. 1
PAPER PHYSICS
Modelling of concentrated fibre suspension pipe flow with low-reynolds-number k-ε turbulence models: new damping function
Carla Cotas, Fernando Garcia, Maria Graça Rasteiro and Dariusz Asendrych
Abstract
Computational Fluid Dynamics can be applied in the pulp and paper industry to simulate the flow of pulp in the different process stages. The present study is focused on the turbulent pipe flow of concentrated Eucalyptus pulp suspensions using ANSYS FLUENT® CFD software. A pseudo-homogeneous strategy was applied, which assumes the non-Newtonian behaviour of the pulp defined by a functional dependence of viscosity on shear rate and consistency. Also, the existence of a water annulus at the pipe wall, surrounding the core flow, was considered. A low-Reynolds-number k-ε turbulence model was evaluated to describe the presence of the drag reduction effect. Furthermore, t he turbulence model was modified taking into account damping functions applied successfully in literature to study power-law fluid flows and particulate flows, which, nevertheless failed to describe adequately the flow of the present complex systems. Therefore, further modifications to the damping function for the case of fibre suspensions were investigated. Pressure drop was used as a control parameter to validate the CFD model. A good correspondence between numerical and experimental data was achieved when using a modified version of the damping function for particulate flows. A good replication of in-house experimental information was obtained for the cases tested
Keywords
Ansys fluent, Drag reduction, Low-Reynolds-number k-ε turbulence models, Rheology, Turbulent pulp flow
Pages
132-147
DOI
10.3183/NPPRJ-2017-32-01-p132-147
Price
22 EUR (excl. VAT) Buy PDF
Nordic Pulp & Paper Research Journal (NPPRJ) is an international scientific magazine covering science and technology for the areas of wood or bio-mass constituents, pulp and paper and including new fiber-based materials, recovery and by-products from pulping processes, bio-refining and energy issues. Articles meeting required scientific standards are accepted from any continent.
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ISSN: 0283-2631