Modeling of Droplet Drying in Spray Chambers Using 2D and 3D Computational Fluid Dynamics

Abstract

Steady-state and unsteady-state 2D axisymmetric and 3D calculations of heat and mass transfer processes in cylinder-on-cone spray chamber have been performed. The theoretical model of the process is based on two-phase Eulerian-Lagrangian approach for gas-droplet flow. In steady-state, two cases are considered: flow of hot air only (no liquid spray) and heat and mass transfer between water spray and hot air. For unsteady-state, droplet-droplet interactions in the water spray are included. It has been found that 2D axisymmetric model is suitable for fast and low-resource consumption numerical calculations and it predicts values of velocity, temperature, and vapor mass fraction in the spray chamber with reasonable accuracy. However, due to its restrictions, 2D axisymmetric model fails to predict asymmetry of flow patterns and presence of the transversal air flow and it cannot provide an actual three-dimensional picture of particle trajectories inside the spray chamber. In the case when the above characteristics are important, the utilization of 3D model is essential.

Keywords:

• Computational fluid dynamics
• Droplet drying
• Flow pattern
• Spray chamber
• Two-phase flow