Study on Flow in Horizontal Agitated Thin-Film Evaporators : 1st Report, Liquid-Fillet in Steady Two-Dimensional Flow

Abstract

A liquid-fillet is formed in front of the rotor blades in thin-film evaporators. The shape of the fillet varies along the axis so that an axial flow is induced in the fillet. Furthermore, the shape of the fillet varies periodically as the blades rotate due to the circumferential variation of the gravitational effect. However, these secondary effects are disregarded and steady two-dimensional flow in the circumferential direction is theoretically examined. The influences of the viscosity and the amount of fluid in the casing as well as the tip clearance effect of blades on the thickness of the liquid-fillet are predicted, and good agreement with experimental data is demonstrated. The secondary effects disregarded in the present analysis will be presented in following papers.