New Experimental Set-up for Studying the Effect of Turbulence on Particle-bubble Interactions
Varying flow regimes,particle populations and consequently different types of bubble-particle interactions characterize the different zones of a flotation cell.The understanding of the role of the different zones of turbulent intensity on the particle-bubble interactions is of primary importance to optimization and scale-up of flotation processes and machinery.In order to study particle-bubble interaction in turbulent flow a completely new approach was taken.A laboratory scale stationary turbulence device was developed and built.The set-up allows the observation of particle-bubble interactions in various turbulence intensities,particle and bubble sizes and surfactant concentrations.The experimental set-up consists of a transparent,specially designed tank in which liquid flows between carefully designed and placed obstacles that create different turbulent flow fields.Bubble-particle aggregates are introduced into this turbulent zone.The behaviour of the aggregates,such as attachment/detachment of particles to/from air bubbles is recorded by a High Speed Imaging (HSI) system (5400 fps).The images are then analysed and the dependence of attachment/detachment process is described as a function of turbulent intensity in different conditions for different surfactant concentrations.This paper introduces this method to study particle-bubble interactions in turbulent flow and correlation to Computational Fluid Dynamics (CFD) simulation.CFD modelling is validated for two and three phase systems;liquid-gas with liquid and solid tracers respectively.The CFD simulations using the RANS k-∑ turbulence model showed good correlation to the experimental data and the experimental method is a promising tool for investigation of particle-bubble interaction in turbulent flow.
Turbulence Particle-bubble interactions High speed imaging CFD
N.Schreithofer G.Wierink Z.J(a)vor B.Omelka K.Heiskanen
Laboratory of Mechanical Process technology and Recycling,Helsinki University of Technology,Finland
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
4183-4190
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）