Interrelations among mixing time, power number and discharge flow rate number in baffled mixing vessels

Abstract

Interrelations among the non-dimensional mixing time, the power number and the discharge flow rate number for baffled mixing vessels are experimentally investigated for paddles and turbines of various dimensions. The correlation equations with the geometrical dimensions of the impellers are presented for the mixing time, the power number and the discharge flow rate number, respectively. The power number can be directly correlated to the discharge flow rate number to the 1.34 power. The mixing time is proportional to the time required to circulate the discharged liquid once, as proposed by van de Vusse in 1955. The number of times of circulation of the liquid to reach the mixing time is correlated with the geometrical dimensions of the impellers. The relations of the nondimensional mixing time with the power number or with the discharge flow rate number are presented. The impeller with larger diameter, larger breadth and greater number of blades is recommendable within the experimental range for turbulent mixing from the point of view of energy saving. © 1985, The Society of Chemical Engineers, Japan. All rights reserved.