Measuring turbulence in a flotation cell using the piezoelectric sensor

Abstract Turbulence and its distribution are of great importance in flotation processing and has been the subject of much research. However, there is no mature technique to measure turbulence in three phase (liquid–solid–gas) systems. In this research, the Piezoelectric Vibration Sensor (PVS) was developed, based on previous research, as a promising tool for turbulence measurements in industrial flotation environments. A frequency response model was established to calculate force applied to the sensor. Experimental results and comparison with Laser Doppler Anemometry (LDA) measurement data showed that the PVS can measure intensity of kinetic energy fluctuation ( σ v 2 ), which has been found in experiments to correlate with turbulent kinetic energy (TKE), a parameter often related to flotation performance in the literature. The sensor was then applied to a 60 l laboratory batch cell running at different impeller speeds and air flow rates to obtain turbulence profiles. Results showed that the piezoelectric sensor is fully capable of measuring turbulence in a multi-phase environment.

[1]  S. A. Sherif.  On the propagation of random errors of constant-temperature anemometers in nonisothermal flows , 1997 .

[2]  F. E. Jørgensen,et al.  How to measure turbulence with hot-wire anemometers - a practical guide , 2002 .

[3]  George Keith Batchelor,et al.  An Introduction to Fluid Dynamics. , 1969 .

[4]  A. Doudou,et al.  Estimation of turbulence spectra in flows of hard conditions sensed with LDA , 2007 .

[5]  R. F. Mudde,et al.  Application of LDA to bubbly flows , 1998 .

[6]  H. Schubert.  On the turbulence-controlled microprocesses in flotation machines , 1999 .

[7]  Pavlos Vlachos,et al.  Methods for Digital Particle Image Sizing (DPIS): Comparisons and improvements , 2009 .

[8]  F. Farhani,et al.  Practical considerations for validity of constant temperature anemometer flow measurements in industrial applications , 2010 .

[9]  Ian Grant,et al.  The effect of flow turbulence and interrogating beam profile on particle image velocimetry fringes , 1989 .

[10]  Sami Grönstrand,et al.  Effect of turbulence models on prediction of fluid flow in an Outotec flotation cell , 2009 .

[11]  D. A. Deglon,et al.  The effect of energy input on the flotation of quartz in an oscillating grid flotation cell , 2012 .

[12]  S. A. Sherif.  Hot-wire/film anemometry measurements in flows with heat transfer and signal correction , 1998 .

[13]  Lin Li,et al.  Numerical simulation of a self-absorbing microbubble generator for a cyclonic-static microbubble flotation column , 2010 .

[14]  Ian Grant,et al.  Modern developments in particle image velocimetry , 1988 .

[15]  Pavlos Vlachos,et al.  Evaluation of multiphase flotation models in grid turbulence via Particle Image Velocimetry , 2006 .

[16]  Bjørn H. Hjertager,et al.  LDA measurements and CFD modelling of gas-liquid flow in a stirred vessel , 1996 .

[17]  Michael Yianneskis,et al.  Assessment of Sliding Mesh CFD Predictions and LDA Measurements of the Flow in a Tank Stirred by a Rushton Impeller , 1998 .

[18]  Kym Runge,et al.  Development and application of a technique for evaluating turbulence in a flotation cell , 2012 .

[19]  K. Ikemura.  Development and application , 1971 .

[20]  I. Pappas,et al.  Current Mode Interfacing Circuit for Flow Sensing Based on Hot-Wire Anemometers Technique , 2011 .

[21]  Dee Bradshaw,et al.  Influence of turbulence kinetic energy on bubble size in different scale flotation cells , 2013 .

[22]  Clive A. Greated,et al.  CHAPTER 15 Particle Image Velocimetry ( PIV ) in the Coastal Engineering Laboratory , 2022 .

[23]  N. Sad Chemloul,et al.  Particle velocity detection and measurement in two-phase flow using combined electronic logic system and LDA technique , 2010 .

[24]  Kai Fallenius.  Turbulence in flotation cells , 1987 .

[25]  Julian F. Scott,et al.  An Introduction to Turbulent Flow , 2000 .

[26]  Marko Laakkonen,et al.  Local bubble size distributions, gas–liquid interfacial areas and gas holdups in a stirred vessel with particle image velocimetry , 2005 .