Discrete element modelling of screw conveyor-mixers

Aca Jovanovic,Lato Pezo,Nenad Kosanic,Sanja Stanojlovic,Ljubinko Levic

doi:10.2298/hemind130412026j

Aca Jovanovic, Lato Pezo + Show 3 more

Open Access

https://doi.org/10.2298/hemind130412026j

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Abstract

Screw conveyors are used extensively in food, plastics, mineral processing, agriculture and processing industries for elevating and/or transporting bulk materials over short to medium distances. Despite their apparent simplicity in design, the transportation action is very complex for design and constructors have tended to rely heavily on empirical performance data. Screw conveyor performance is affected by its operating conditions (such as: the rotational speed of the screw, the inclination of the screw conveyor, and its volumetric fill level). In this paper, horizontal, several single-pitch screw conveyors with some geometry variations in screw blade was investigated for mixing action during transport, using Discrete Element Method (DEM). The influence of geometry modifications on the performance of screw conveyor was examined, different screw designs were compared, and the effects of geometrical variations on mixing performances during transport were explored. During the transport, the particle tumbles down from the top of the helix to the next free surface and that segment of the path was used for auxiliary mixing action. The particle path is dramatically increased with the addition of three complementary helices oriented in the same direction as screw blades (1458.2 mm compared to 397.6 mm in case of single flight screw conveyor) Transport route enlarges to 1764.4 mm, when installing helices oriented in the opposite direction from screw blades. By addition of straight line blade to single flight screw conveyor, the longest particle path is being reached: 2061.6 mm

Highlights

Screw conveyors are used extensively in food, plastics, mineral processing, agriculture and processing industries for elevating and/or transporting bulk materials over short to medium distances
Applied Discrete Element Method (DEM) analysis, the mutual influence of different configuration of helix geometry and observed particle, is focused to inspect the possibility of prolonging single particle path during transport
One of the key factors that the modeler should be aware in DEM analysis is shortening the central processing unit (CPU) time and the reduction of other computer resources, by making these basic assumptions

Summary

Introduction

Screw conveyors are used extensively in food, plastics, mineral processing, agriculture and processing industries for elevating and/or transporting bulk materials over short to medium distances. The particle path is dramatically increased with the addition of three complementary helices oriented in the same direction as screw blades (1458.2 mm compared to 397.6 mm in case of single flight screw conveyor). Discrete element modeling (DEM), of particulate flow in a screw conveyor was first reported by Shimizu and Cundall (2001) [4] They examined the performance of horizontal and vertical screw conveyors and compared their results with previous work and empirical equations. With several additional elements welded on screw blade can significantly increase the homogeneity and reduce the segregation of materials by particle size

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