Development of an advanced imaging technique for dynamic emulsion stability

•Experimental study of oil-water emulsion stability in an impeller stirred tank.•Development of imaging technique for dynamic droplet size analysis.•Theoretical assessment of droplets for the inertial and viscous sub ranges.•Measurement of parameters characterizing the droplet stability.

Oil-water emulsions consist of droplets that are approximately spherical in shape and with a distribution in size. An image processing technique that can be used for studying emulsion droplet stability behaviour in multiphase flow has been developed. In this work, the developed technique is used to study a model system, comprising Nexbase (with and without SPAN 80 surfactants) oil and saline water emulsion in a stirred tank system. A state of the art stirred tank experimental set up was constructed that measured dynamic droplet size evolution with varying impeller speed and torque. The equilibrium droplet size measurement and torque data were used to validate with theoretical inertial (Hinze model) and viscous subrange models. Besides, this method was successfully used to obtain droplet size relaxation coefficients with varying impeller speeds.