Particle and fluid motion on spiral separators
ABSTRACT Techniques for predicting the primary fluid flow profile and the secondary circulation on spiral troughs are summarised and revised equations for calculating the flow velocities are presented. Recent experimental studies of the fluid motion at both the trough base and the free surface are reported and compared with the predicted tracks of fluid elements at various positions within the flow.The use of a trajectory approach to estimate the motion and distribution of particles across the trough during a separation is reviewed, and the problems associated with the comparison of hydrodynamic data with measured results expressed in terms of sieve apertures are discussed. A suitable correlation technique is proposed and applied to preliminary results from a fundamental study of the behaviour of individual size fractions of glass spheres and quartz sand. The predicted recoveries of a gold ore on three different spiral separators are also compared with measured results on a size by size basis.
- SourceAvailable from: Ahmed Abdel Gawad[show abstract] [hide abstract]
ABSTRACT: The aim of the present study is the simulation of the particulate flow in spiral separators. The study is based on Eulerian approach and turbulence modeling. The results focus on particulate-flow characteristics such as the velocity, the distribution, and concentration of particulates on the spiral trough. The predicted results are compared with the experimental findings from LD9 coal spiral. The comparison shows good agreement and indicates that the most accurate turbulence model is RNG K–ε.Applied Mathematical Modelling 01/2013; 37(1-2):198-215. · 1.71 Impact Factor
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ABSTRACT: In previous work an analysis of the primary flow and secondary circulation on a spiral was developed, based on the use of the Manning equation to describe the flow on the inner part of the spiral and the free vortex equation to characterise the flow on the outer section. More recent studies have advocated the use of the Laminar equation or a new relationship based on the Bagnold shear force.The theoretical basis is modified in the present contribution to permit the estimation of the primary flow on large diameter spiral troughs where the whole of the free surface is part of the vortex flow. Flow predictions for two different large diameter spirals are presented.Minerals Engineering - MINER ENG. 01/2009; 22(4):352-356.
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ABSTRACT: A spiral separator is one of the commonly-used gravity-concentration devices. It has been widely used in the mineral processing of coal. Also, it is used for the inexpensive pre-concentration of low grade ores. Spiral separator consists of an open trough that twists downward in helical configuration about a central axis. The aim of the present study is the simulation of the flow of water in spiral separators. The study is based on volume of Fluid (VOF) approach and turbulence modeling. The results focus on waterflow characteristics such as the depth of water as well as the turbulence intensity. The results demonstrated that the water depth and turbulence intensity on spiral trough increase smoothly outward. Predicted results are compared with the experimental findings from LD9 coal spiral. Comparison between the predicted and the measured values show good agreement and the most accurate turbulence model is RSM.Journal of Engineering Sciences, Faculty of Engineering, Assiut University, Egypt. 07/2008; 36(4):935-950.