Phase inversion in liquid–liquid pipe flow

This paper covers the phase inversion phenomenon which occurs when an unstable, two-phase liquid–liquid system flows through a horizontal pipe. A short review has been provided for the methods applicable when establishing inversion conditions for stable emulsion systems. As regards phase inversion which takes place in unstable, liquid dispersion systems, the course and findings from our experiments have been described. The experiments involved the mixtures formed by water and four types of oil, and various methods were used for determination of the type of the liquid–liquid system, as well as conditions at which inversion occurred. The experimental findings made it possible to develop a method for determination of the type of an unstable liquid–liquid system which is just flowing, and hence for unequivocal indication of the types of continuous and disperse phases. The suggested method can be easily employed in practice since only the physical properties of both liquids and their mass flux densities need to be taken into consideration.