EFFECT OF TEMPERATURE ON THE FLOW PROPERTIES OF SUSPENSIONS

Fine powder of CaCO3 was dispersed in H2O, ethylene, glycol (EG), and 50% aqueous solution of polyethylene glycol (PEG). In all cases, the apparent viscosity, η, of the suspensions decreased with temperature. The results are discussed on the basis of the energy dissipation theory. The total energy dissipation of flow, ET(=ηaD2), per cm3 per sec was divided into two terms, i.e., Ep due to the interaction of flow units (flocs) and Ev, the viscous energy. Ev plays a dominant role when the viscosity of the medium, ηo, is large (e.g., for EG), whereas Ep is responsible for the overall flow behavior for the system with small ηo (e.g., for H2O). From the analysis of Ep with respect to the rate of shear, D, and the effective floc concentration, a parameter m2 was obtained, which is independent of D and of solid concentration, and serves as a measure of the extent of energy dissipation due to the interaction between flocs. © 1979.