DESIGN OF A GAS–LIQUID UNBAFFLED STIRRED TANK WITH A CONCAVE BLADE IMPELLER

Experimental investigation of unbaffl ed multiphase (gas–liquid) stirred tanks is conducted with the use of a concave blade impeller to analyze mass transfer, gassed power, and gas holdup. The experiments are carried out with various impeller diameter to tank diameter ratios and impeller clearances. The design criterion for the mass transfer rate is proposed, and its prediction capability is found to be satisfactory. The results show that the gassed power is dependent on the impeller diameter to tank diameter ratio and impeller clearance. The design criteria for gassed power to ungassed power ratio and gas holdup are also introduced. Multiphase modeling is done by employing the computational fl uid dynamics (CFD) techniques to observe the characteristic fl ow pattern transition and to carry out a qualitative analysis of the mass transfer rate.
   
Author:  T. T. Devi and Bimlesh Kumar
Keywords:  concave blade impeller, gas holdup, impeller clearance, mass transfer, power number, stirred tank
Page:  76