CFD simulation on droplet behaviour in post-dryout region

Abstract

Abstract The investigation on heat transfer in post-dryout region is of great significance to determine the maximum wall temperature when dryout occurs. In this paper, the superheated vapor is considered as Eulerian continuous phase. With DPM (Discrete Particle Method) in the ASNSYS Fluent, droplets will be tracked with Lagrangian method. Heat, momentum and mass are exchanged between the two phases inside Eulerian control volumes. The stochastic tracking is included to investigate the effect of turbulence in the continuous phase on the droplet motion. The results show that the wall temperature profile differs a lot under different initial droplet sizes. By summary of the droplet evaporation rate, it’s found that less than 2 % evaporation happens directly on the wall surface, while evaporation mostly happens in the vapor layer near the wall.