average shear rate estimation in conventional stirred-tank bioreactor using non-newtonian fluid: an experimental approach

An experimental approach for the estimation of average shear rate (γav) in a stirred tank bioreactor has been proposed for the turbulent flow regime. based on the proposed methodology, the correlation for the estimation of γav was obtained as a function of agitation speed (n), superficial gas velocity (vs), and the rheological properties of the non-newtonian fluids. the γav estimated by the present method was found to be within the range of values calculated by correlations available in the literature. the γav increased with the increase of agitation and sparging in all the conditions tested. the correlation derived in the present work helps in the estimation of γav as a function of bioreactor geometry along with physical conditions (n and vs), and rheological properties (n and k) of non-newtonian fluid in commercially available stirred tank bioreactor.