The effect of rotational speed on granular flow in a vertical bladed mixer

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F44555601%3A13440%2F15%3A43886673" target="_blank" >RIV/44555601:13440/15:43886673 - isvavai.cz</a>

Alternative codes found

RIV/67985858:_____/15:00451672 RIV/60461373:22340/15:43899859

Result on the web

<a href="http://dx.doi.org/10.1016/j.powtec.2015.04.035" target="_blank" >http://dx.doi.org/10.1016/j.powtec.2015.04.035</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.powtec.2015.04.035" target="_blank" >10.1016/j.powtec.2015.04.035</a>

Result language

angličtina

Original language name

The effect of rotational speed on granular flow in a vertical bladed mixer

Original language description

Granular mixing is an important unit operation used to ensure the uniformity of mixture properties. Unfortunately, the mechanisms of particles' motion and the role of operation parameters remain poorly understood. In this work, granular mixing is studied using computer simulations via DEM (discrete element method). The examined process is the mixing of approximately 42 thousand glass spherical particles with a 2. mm diameter in a vertical cylindrical mixer with two opposed flat blades with a 45o rake angle. The effect of different blade rotational speeds (varying from 0.1. rpm to 960. rpm) on the formation and evolution of flow patterns is investigated. Examining individual particle trajectories shows that the particles exhibit two basic types of periodic movements. The first one, characterized by a higher frequency, is related to the motion of the stirrer. The second one (lower frequency) is associated with recirculations in the vertical plane. A methodology for their detection is proposed. The observed recirculation zones are the secondary flow commonly occurring in liquid mixing cases and also the mechanism of their emergence is similar. Unlike liquids, the mixing of granular systems exhibits a greater diversity of recirculation zones. The tangential motion does not create complex structures in the angular direction, because the height of the granular layer is several times greater than the height of the blade. For this reason, we have focused only on the tangential velocity distribution in the radial and axial directions. Three global particle transport characteristics describing the mixing process in the tangential, axial and radial directions were proposed. Significant changes in the behavior of these variables were used to distinguish six dynamical regimes of granular mixing depending on the blade rotational speed. These regimes are characterized by different flow patterns.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

CI - Industrial chemistry and chemical engineering

OECD FORD branch

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Project

<a href="/en/project/GAP105%2F12%2F0664" target="_blank" >GAP105/12/0664: Hydro-mechanical interactions of particles in solid-fluid systems</a><br>

Continuities

S - Specificky vyzkum na vysokych skolach

Publication year

2015

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Powder Technology

ISSN

0032-5910

e-ISSN

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Volume of the periodical

280

Issue of the periodical within the volume

August 01, 2015

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

11

Pages from-to

180-190

UT code for WoS article

000356208700020

EID of the result in the Scopus database

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