DOI: 10.1615/ICHMT.1997.IntSymLiqTwoPhaseFlowTranspPhen
ISBN Print: 1-56700-162-9
FLOW OF HIGH INTERNAL PHASE RATIO EMULSIONS THROUGH PIPES, ORIFICES AND NOZZLES
ABSTRACT
The flow behavior of high internal phase ratio emulsions through pipes of 3.5, 5.6 and 21 mm internal diameters, orifices with D0/Di ratios of 0.2, 0.4, 0.6 and 0.8 and nozzles with uniform decrease in diameter is investigated in this work. W/O type emulsions were formed with 1% sorbitol solution as the aqueous dispersed phase and light mineral oil as the continuous oil phase and polyoxyethelene(2) oleyl ether as the surface active agent. Slip flow is observed in 21 mm internal diameter stainless steel pipes where the shear stress at the wall is not excessive. The emulsion undergoes a structural change through which the viscosity increases sharply in the small diameter pipes, where the wall shear stress is considerable. 88% emulsions, liable to changes in drop configuration are affected the most by variations in the wall shear stress. Elongational viscosities can be correlated with the rate of extension only if all of the surface active agent is present in the films separating the dispersed phase and not in the plateau borders which can act as reservoirs. The phase ratio becomes a factor only in orifices with D0/Di ratio of 0.4, where maximum pressure differences are observed.