Numerical study of heat transfer characteristics of drop-wall interaction using multiphase smoothed particle hydrodynamics

Predicting the characteristics of droplet impinging on a solid surface is important for various industrial applications. However, it is difficult to measure the heat flux, energy consumption, and droplet evaporation in details. To analyze the quantitative estimation of heat transfer characteristics during droplet impacting, a numerical method based on Smoothed Particle Hydrodynamics (SPH) with an enhanced heat transfer model is presented in the present work. Comparing with previous work, the physical properties of materials and thermal boundary layer thickness are considered to optimize the model. The heat flux and the temperature field of droplet and solid wall are demonstrated to explain how the droplet is heated and how the wall is cooled. The SPH method is validated against experimental and numerical results from literature. Then numerical simulations of droplet impact on a solid dry surface are performed to investigate the drop spread factor, drop mean temperature, surface central temperature, heat flux, and cooling effectiveness. To further investigate the relations between the physical properties and find models for engineering applications, the numerical data are fitted with functions. The results indicate that the temperature difference performs the key role in cooling the wall and heating the drop, while the Weber number mainly influences the total thermal energy convection by determining the size of contact area. On the one hand, as the temperature difference increases, the droplet absorbs more energy and the surface is cooled more significantly. On the other hand, the increment of Weber number results in a larger contact surface and strengthen the effect of heat removal. The results reveal the thermal and dynamic mechanism of heat transfer during drop impact process.