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Skjaeraasen O.,Institute for Energy Technology of Norway | Skjaeraasen O.,The Multiphase Flow Assurance Center | Skartlien R.,Institute for Energy Technology of Norway | Skartlien R.,The Multiphase Flow Assurance Center | And 2 more authors.
Journal of Dispersion Science and Technology

A model for turbulent suspensions involving two-way coupling between a liquid carrier phase and a solid dispersed phase is presented. Closure relations are obtained from particle kinetic theory, with both drag and virtual mass effects taken into account. It is shown that the feedback on the flow due to the particles mainly depends on the particle concentration, the characteristic Stokes numbers, and the density ratio between the particle and liquid phases. Over a broad parameter range, we find that drag coupling gives turbulence damping and an increased streaming velocity. Added mass coupling has the opposite effect. Some of the model predictions are compared with data given in the literature, and with PIV experimental data. It is found that the model is generally consistent with experiments; in particular, when it comes to the observed turbulence damping and drag reduction effects. The model can be used as a stand-alone tool to calculate turbulent stresses, mean velocities and concentration profiles of both phases. Alternatively, it can serve as basis for a reduced parametric model of particle feedback effects on; for example, the eddy viscosity, and thus the pressure drop and superficial speed. © 2015, Copyright © Taylor & Francis Group, LLC. Source

Langsholt M.,Institute for Energy Technology of Norway | Langsholt M.,The Multiphase Flow Assurance Center | Zarruk G.A.,Institute for Energy Technology of Norway | Zarruk G.A.,The Multiphase Flow Assurance Center
Journal of Dispersion Science and Technology

Suspension flow experiments carried out in a horizontal test pipe with D = 60 mm are presented. Three different particle types with different densities and all with diameters ∼250 µm were used. The particle volume concentrations were 0.5%, 2%, and 5%. Bulk velocities were chosen in order to capture homogeneous and heterogeneous flow regimes. The objective was to acquire experimental data suitable for model development and testing for semi-dilute suspensions, where existing data are sparse. A traversing gamma densitometer was used to measure the particle fraction. Axial velocity and turbulence intensity profiles, for the particles only, were measured with a laser Doppler anemometer. © 2015, Copyright © Taylor & Francis Group, LLC. Source

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