Oxygen transfer into newtonian and non‐newtonian fluids in mechanically agitated vessels

Oxygen transfer into Newtonian and non‐Newtonian fluids was studied in stirred tank vessels of 0.0018, 0.006 and 0.036 m 3 operating volumes. Emphasis was given to the rheological effects of the pseudoplastic medium on the volumetric oxygen transfer coefficient, K L a . Results indicate that K L a is a strong function of gassed power input per unit volume ( P g /V ) for the Newtonian fluid, but a weak function of P g /V for the non‐Newtonian fluid, and a strong function of superficial gas velocity ( V s ) for both fluids for paddle‐type impellers. K L a is found to decrease rapidly with an increase in apparent viscosity for values of μ a greater than 2.0 Pa · s. In addition to various correlations, a dimen‐sionless correlation including the impeller Reynolds number, impeller Weber number, and the aeration number is presented for the prediction of K L a in a gas‐liquid non‐Newtonian system.