Two-phase momentum flux in pipes and its application to incompressible flow in nozzles

Abstract

The pressure drop produced when a single-phase gas or liquid flows through a nozzle can be reasonably well estimated from inviscid flow theory. A similarly based model, taking the slip with entrained liquid fraction approach, has been developed for two-phase gas—liquid flows. Fundamental to the model is the constraint that the nozzle flow depends on the entry conditions, particularly the momentum flux. At low qualities the tendency was for fractions of the liquid flow to be accelerated with the gas phase to maintain uniform momentum flux across the nozzle flow area. At higher qualities the gas core of the annular flow, along with its associated droplets, was found to contract with negligible interaction with the surrounding liquid film. The model has been compared with data sources and other models available in the literature and shown to perform well.