Bubble size distribution: comparison between six-bladed curve blade impeller and Rushton Turbine

In this work, bubble size distribution generated by six-bladed curve blade impeller (6CB) was compared with Rushton Turbine (6RT) in a 40 em diameter cylindrical tank for gas-liquid and gas-liquid-solid systems. Bubbles were drawn out from the tank using a suction pump and captured by digital camerawhen the bubbles passed through a specially built cylindrical perspex tube. The Sauter mean diameter, d32 and distribution curves were compared at 5 L/min aeration rate and 60, 80 and 100 rpm for two (0% inert solid) and three phase systems (addition of 2% wt inert solid). The investigation showed that at 60 rpm, d32 for 6CB was lower than 6RT by about 10% at locations very close to the impeller region. However. at higher agitation speed (80 and 100 rpm). 6RT recorded lower d32 values than 6CB. Addition of solid 2% wI inert solid was found to decrease the d32 values (compared to gas-liquid system) but became almost similar and a bi-modal distribution was also observed for both the impellers.