Modeling of droplet/wall interaction based on SPH method

摘要

Fuel droplet impingement on different wall conditions have been studied using Smoothed Particle Hydrodynamics (SPH) method, and a new splashing sub-model is proposed based on numerical results to calculate the splashing mass fraction of the incident droplet and compared with experimental results. Temporal evolution of the droplet shape after impingement is studied with various initial and boundary conditions. It is found that few splashes take place when the drop hits a relatively smoothed dry surface. Wall film plays a great role on droplet splashing. On one hand, the film slows down the droplet spreading process and transmits the energy to the crown part, making it easier to splash; on the other hand, the incident energy is dissipated when the drop moves through the film. The result shows that when non-dimensional wall film (h_(nd)) is less than 0.5, the splashing mass fraction is relatively high and secondary droplets are easier to form. Further increase h_(nd), the fraction goes down and more film part splashes. The splashing sub-model is fitted and modified using numerical data and experimental data in a wet wall case. The result shows that the splashing mass and secondary droplets can be predicted as a function of We using the proposed sub-model.