A population balance method for simulation of particle-induced droplet breakup in spray flame synthesis and suspension spray combustion

Abstract

A population balance method based on weighted Monte-Carlo droplets is used to investigate breakup phenomena in single droplet combustion and spray flame synthesis (SFS). Particle shell formation in conjunction with superheating of liquid components is shown to be a plausible cause for droplet breakup. The breakage rate is calculated based on temperature and particle concentration profiles inside individual droplets, whereas the breakage function was determined using shadowgraphy imaging of droplets and image analysis. This enabled the simulation of consecutive breakup events in single droplet combustion and SFS. Furthermore, in the context of population balance simulations, an adaptive grid method is introduced for the calculation of particle accumulation at the droplet surface. This method is applicable to quickly evaporating droplets where particle transport by advection is fast compared to transport by radial diffusion. The new adaptive grid method is evaluated by comparison with seven single droplet combustion experiments from literature. More than that, parallel algorithms for a computationally efficient implementation using graphics processing units (GPUs) are discussed.

Keywords

• Spray combustion
• Droplet breakup
• Shadowgraphy imaging
• Population balance simulation
• Graphics Processing Unit (GPU)
• SpraySyn reactor