Mixing in Eccentrically Located Hi-F Mixer

Abstract

The high performance of a large impeller can be combined with the advantages of an eccentric mixer by using the impeller at an eccentric position. In this study, the power consumption, mixing time, and dispersion performance of an eccentrically located Hi-F mixer, which is a type of large impeller, were investigated. Furthermore, the sloshing phenomenon was investigated. The power consumption, P, and mixing time, θ_M, were measured under various eccentric conditions. The relation between the power number (N_p) and Reynolds number (Re) and that between the dimensionless mixing time (n · θ_M) and Re were investigated. The curves representing these relations were similar to curve that is characteristic of concentric mixing with baffles. Equations for estimating N_p and n · θ_M were proposed. To investigate the dispersion performance for low- and medium-viscosity liquids, the suction rotational speed, n_s, and the dispersion rotational speed, n_d, were measured. The dispersion performance of eccentric mixing was higher than that of concentric mixing without baffles. In the medium-viscosity liquids, the performance of eccentric mixing was higher than that of concentric mixing with baffles. When the Hi-F mixer was used under eccentric conditions, rotary sloshing was generated at a specific rotational speed. The sloshing rotational speed, n_slosh, was independent of the eccentric length, liquid properties, etc. An equation for estimating the n_slosh from D and d_L was obtained.