화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.36, No.11, 5028-5036, 1997
Hydrodynamics of Dispersed Liquid Droplets in Agitated Synthetic Fibrous Slurries
The hydrodynamic and liquid particle dispersion processes in agitated vessels containing dilute liquid-liquid dispersions, and dilute liquid dispersions in synthetic fibrous slurries, were experimentally studied, A transparent cylindrical vessel 25 cm in height and 15.5 cm in diameter equipped with a six-blade impeller, with geometric proportions representing the standard vessel configuration, was used. The steady-state size distributions of molten wax particles, which constituted 1% by weight of the mixture everywhere, in pure water, and in aqueous slurries with 0.1%, 0.5%, 0.8%, and 1.0% consistencies of nylon fibers, were measured using sampling and microscopic image analyses, The average nylon fiber length and diameter were 6.22 mm and 19.5 mu m, respectively. With pure water the molten wax particle size distributions were spatially homogeneous and bimodal everywhere and confirmed locally isotropic turbulence in the vessel. In tests with fibrous slurries, for fiber consistencies smaller than 1%, the molten wax particle size distributions remained spatially homogeneous and agreed with the locally isotropic turbulence assumption. However, they were unimodal everywhere with narrow particle diameter spectra. Increasing the fiber-consistency and impeller speed both lead to smaller mean molten wax particles and narrower particle diameter ranges, suggesting that fibers hamper particle collision and coalescence. With 1% fiber consistency, widespread flow stratification and fiber flocculation took place.