Investigation of Emulsion Formation in Couette Flow
Sprache des Vortragstitels:
the 16th Food Colloids Conference
Sprache des Tagungstitel:
The mixture of two immiscible liquids, where one of them is dispersed (dispersed phase) in the other (continuous phase) is called emulsion (Umbanhowar et al. 2000). Emulsions play a key role in many processes including food, pharmaceutical, polymer and chemical industries. Droplet formation and its interfacial phenomena, which determine the droplet size distribution, are essential issues in liquid-liquid systems (Paul et al. 2003). Emulsion formation was studied, for example, by Grace (Grace 1982), where he studied the droplet breakup in a laminar Taylor-Couette flow. His data shows that in simple shear flow droplet break up is not possible for viscosity ratios (dispersed over continuous) larger than 4. However, there is considerable lack of sufficient data about droplet size distribution in both laminar and turbulent regimes in couette flows.
Thus, the main objective of this work is to find the drop size distribution versus the variation of Reynolds number (of the continuous phase). The experimental setup consists of an ordinary concentric Taylor-Couette flow device and a high-speed camera. Emulsion systems are created by mixing several oils with distilled water. A surfactant is not present in this work, in order to study the pure effect of the continuous phase inertia force in the turbulent regime as well as of the viscous force in laminar regime. Finally, the captured images are analysed by using a freeware image analysis software (ImageJ). The results show that the drop size distribution becomes wider as the Reynolds number increases.