Droplet deposition and interchange in annular two-phase flow

Abstract

A mathematical description of droplet entrainment and deposition is presented. This enables both unidirectional deposition and interchange experiments to be analysed. This approach permits description of deposition by both the diffusion like mechanism conventionally used and by the direct impaction mechanism which has recently been identified. A criterion has been derived to differentiate between the two mechanisms of deposition based on the balance between the initial drop momentum and the drag force of a turbulent eddy. The transition criterion has been substantiated with experimental data derived from unidirectional deposition experiments. A preliminary examination of interchange data has been carried out.