This page estimates mixing time (time to homogeneity) in a stirred tank. It calculates the Reynolds number (density * speed * impeller diameter squared / viscosity) to check flow regime. For turbulent flow (Re > 10,000), mixing time is approximated as 5.2 divided by (impeller speed in rad/s * the square of the impeller-to-tank diameter ratio). Power number is estimated empirically (~6.3). Laminar/transitional regimes are not calculated.