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A positron emission particle tracking investigation of the scaling law governing free surface flows in tumbling mills
Author(s) -
Govender Indresan,
Richter Max C.,
Mainza Aubrey N.,
De Klerk David N.
Publication year - 2017
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.15453
Subject(s) - froude number , mechanics , scaling , tracking (education) , flow (mathematics) , lagrangian particle tracking , particle (ecology) , positron emission , free surface , physics , kinematics , turbulence , materials science , classical mechanics , geometry , optics , geology , mathematics , psychology , pedagogy , oceanography , tomography
Positron Emission Particle Tracking (PEPT) measurements are used to track the flow of d = 5 mm glass beads within a rotating drum fitted with (and without) lifter bars and operated in the cascading and cataracting Froude regimes. After converting the Lagrangian trajectories of a representative radio‐labeled glass bead (the tracer) into Eulerian fields under the ergodic assumption, the bed shape and kinematics are extracted for steady, fully developed flow conditions. Notwithstanding the azimuthal wall effects introduced by the lifter bars, we show a linear scaling 〈 v 〉 ∝ h of the local flowing layer thickness (h) with local depth‐averaged velocity 〈 v 〉 and a constant average shear 〈 γ ̇ 〉 ∼ 0.6g dfor direct measurements spanning the entire flowing layer (not just the central region), and high Froude regimes (cascading and cataracting) not previously investigated by scaling analysis in the literature. © 2016 American Institute of Chemical Engineers AIChE J , 63: 903–913, 2017