APPARENT VISCOSITY MIXING INDEX USING CFD COMPUTATIONS FOR NON-NEWTONIAN FLUIDS USING HELICAL RIBBON IMPELLER

Abstract

In the present study a mixing index was proposed in order to characterizemixing processes of non Newtonian fluids. The apparent viscosity in amixing tank equipped with helical ribbon impeller was computed using aCFD package. The symmetry plane of the mixing tank was divided intosixteen zones where an average apparent dimensionless viscosity wascalculated to each of these zones from which a mixing index was evaluated.The mixing index showed to increase with impeller rotational speed,impeller/tank diameter ratio and showed to be affected by the rheologicalparameters of the agitated fluid. The computed data of the mixing indexwere correlated as a function of impeller/tank diameter ratio, impellerrotational speed and rheological parameters. The proposed correlationdeviated from computed data by a maximum deviation of ± 50%.