The interest in oil-water pipe flow descends from its importance in petrochemical industries; pumping power requirements during oil transportation is considerably reduced in the core-annular flow regime. In petroleum transportation pipelines, an additional phase of natural gas frequently flows with the oil. The prediction of pressure drop and stability characteristics of the three-phase flow in these lines is important for proper operation of the transportation plants at reduced power consumption. Results from a set of experiments of three-phase flow of high viscosity oil, water and air in horizontal pipes of two different diameters are presented in the paper. Pressure drop measurements are related to three phase flow patterns observations in a defined range of specific flow rates of water, oil and air. When air is supplied in a wavy-stratified flow of oil and water, the presence of air plugs hinders stratification and ensures a lower resistance as respect the corresponding oil-water case; disturbances induced by the gaseous phase grow rapidly with increasing air specific flow rate and the tendency is reversed by a higer flow rate of air. The presence of air in an annular flow of oil induce large quasi-periodic deformations of the interface between oil and water and has a negative effect on drag.
From two phsae oil water to three phase oil/water/air flows in horizontal pipes: pressure drop and flow regimes / G., Sotgia; Stalio, Enrico; Tartarini, Paolo; A., Villa. - STAMPA. - (2006), pp. 425-430. (Intervento presentato al convegno Congresso nazionale UIT sulla trasmissione del calore tenutosi a Napoli nel 21-23 giugno 2006).