Analysis of Droplet Deposition in a Vertical Air-water Dispersed Flow

Abstract

Droplet deposition in a turbulent vertical air–water dispersed flow onto wall of a tube has been studied theoretically and experimentally. A model for the deposition of large droplets based on the droplet sticking efficiency to the tube wall is proposed. Sticking efficiency is defined as the ratio of the sticking mass flux to the impacting mass flux. The application of the proposed model is illustrated by calculating several quantities of a practical interest for analysis of heat and mass transfer in dispersed flows, namely the deposition coefficient onto dry wall, sticking efficiency onto wall liquid film and the minimum value of the liquid film Reynolds number at which a steady liquid film exist. The proposed model describes the change of the deposition coefficient with droplet concentration and fits the obtained deposition data satisfactorily for a wide range of the gas Reynolds numbers and droplet concentration. The model is useful for analysing of dryout and burnout heat transfer regimes.