Numerical simulation of evaporation of droplet impacting on tubular wall with different wettability based on smoothed particle hydrodynamics method

In this paper, the evaporation numerical model of droplet impinging on the tubular wall with different wettability is established based on the smoothed particle hydrodynamics (SPH) method. The liquid phase mass fraction is introduced and integrated with the particle merging technique to address the phase change processes effectively. The flow spreading and heat transfer processes accompanying the phase change during droplet impact on a tubular wall are simulated. Meanwhile, five tubular walls with different wettability are prepared by sanding method and surface active material modification. The corresponding contact angles are 11°, 36°, 58°, 78°, and 112°, respectively. The experimental study of droplet impacts on tubular walls with different wettability is conducted. The reliability and validity of the SPH model are verified by comparing the simulation results with the experimental results. The dynamic process of flow spreading and evaporation of droplets impacting different wettability tubular walls are simulated, and the effects of surface wettability, wall temperature, and impact Weber number on the droplet evaporation process are further discussed and explored. It is found that poor surface wettability hinders droplet spreading and discourages the evaporation process. The spreading factor of the droplet increases with the tubular wall temperature and the impact Weber number. However, the increase in the impact Weber number promotes droplet spreading more significantly than the increase in tube temperature. Enhancing the wall wettability, increasing the tubular wall temperature, and enhancing the impact Weber number are beneficial to the evaporation of the liquid.