Investigation on Mixing Time in a Dual Rushton Impeller Stirred Tank

Mixing time can be used as a comparative measurement of mixers efficiency. The present study is an investigation of the effect of important operating variables (impeller rotational speed and air bubbles present) on the mixing time in an agitated tand by dual Rushton turbine. This study has shown that the mixing time decreases with an increase in impeller speed and the effect of gas flow rate on the mixing time depends on the impeller rotational speeds. The mixing time obtained by conductivity method has been compared with the PLIF technique by Moghaddas. According to the experimental results, the mixing times which were obtained from the conductivity technique have a good agreement with the PLIF technique. Therefore, the conductivity technique is a simple, accurate and cost effective technique to replace expensive way. Also, the mixing time obtained by using the correlation and formula at large scale of mixing systems was incorrect, and the number of available correlation in this scale of mixing systems is limited. In the present study,to predict of mixing time in a dual Rushton impeller stirred, a six-concentration obtained experimentally and that calculated from compartment model was obtained.