ERT Visualization of Gas Dispersion Performance of Aerofoil and Radial Impellers in an Agitated Vessel

The objective of this research work was to determine the gas dispersion performance of an aerofoil impeller and a standard Rushton turbine for gas–liquid mixing an agitated vessel via electrical resistance tomography (ERT) visualization. The experimental work was carried out in a fully baffled 400-mm-diameter agitated vessel that was fitted with four planes of 16 stainless steel electrodes connected to an ITS P2000 ERT system. Agitation was achieved by using a Lightnin Labmaster system mounted on the vessel. The ITS ERT system is equipped with a real-time data acquisition system that has the capability to capture images at up to 20 frames per second. The gas dispersion images were reconstructed using built-in image reconstruction software based on a modified linear back projection algorithm. A Matlab code was also developed to further analyse the gas dispersion by plotting a real-time surface plot from the ERT data. Various gas dispersion conditions such as flooded, transition, and dispersed were successfully visualized and characterized using the ERT technique, and over the range of the experimental works, the standard Rushton turbine was found to be a more efficient than the Lightnin A320 impeller.