Measuring turbulence in a flotation cell using the piezoelectric sensor

• The piezoelectric sensor has been developed as a turbulence measurement tool.
• A new calibration method has been used to obtain the frequency response model.
• Tests in a water only cell have been carried out and compared with LDA data.
• The piezoelectric sensor is found to be measuring kinetic energy fluctuation.
• The piezoelectric sensor is also tested in water and air two-phase systems.

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 (σv2σv2), 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.