Abstract

Enhanced operating performance can be obtained by combining the design characteristics of impellers. The asymmetricity of BT6 impeller blades when combined with symmetric ICI gasfoil blades results in two new diskless impeller designs, one with extension of the upper blade part (PBIUP) and the other with lower blade part (PBIDN). These impellers are experimentally characterized at intense agitation and sparging conditions for power draw, gas holdup and transition regimes. CFD modeling is used to evaluate the performance of impellers based on the pressure distribution and cavity formation on and around the impeller blades. Cavity formation on the new impellers is found to be higher as compared with ICI impeller but lower than BT6. The maximum experimental power drop at intense gas flow and agitation conditions for PBIUP and PBIDN is found to be 14% and 22% as compared to power drop of 10% for ICI gasfoil and 25% for BT6. The coalescence regions, identified from predicted gas holdup profiles, confirmed the experimental observations regarding the formation of larger bubbles in the tank. Overall, PBIUP is found to give uniform gas dispersion as compared to other impellers along with the desired objective of lower power drop.

Recommended Citation

Kshatriya, Sandeep S.; Patwardhan, Ashwin W.; and Eaglesham, Archie (2007) "Experimental and CFD Characterization of Gas Dispersing Asymmetric Parabolic Blade Impellers," International Journal of Chemical Reactor Engineering: Vol. 5: A12.
Available at: http://www.bepress.com/ijcre/vol5/A12