This paper presents a modelling framework for describing annular-mist flows in the process of generating a disparsed phase. The droplet and film phases are described in a statistical manner using a population balance type of equation. The entrainment and deposition phenomena can be described properly in terms of a droplet size distribution. The mathematical model is solved using a spectral method based on the least squares formulation. Numerical examples and validation against experimental data are included for describing the capabilities of the method. (c) 2008 Elsevier Ltd. All rights reserved.