An investigation of droplet impingement on a conical obstacle

Droplet impingement has been intensively studied in recent years due to its wide range of applications. In the present study, a multi-component multiphase Lattice Boltzmann model is adopted to study the droplet impingement on conical obstacles. A modified non-slip bounce-back boundary condition is applied to simulate the wetting of droplets on the hypotenuse of the cones. The model is validated for its capability to achieve ac-curate results, and then the effect of gravity, as well as surface wettability and surface temperature is investi-gated. Three different droplet behaviours are observed upon the impingement, respectively, namely, rebounding and wrapping the vertex, sliding down against the hypotenuse, and sliding down levitated. The increase in gravity and hydrophilicity reduces the chance of the droplet wrapping the vertex, while the increase in hydro-phobicity and temperature increases the chance of the droplet sliding down levitated. A detailed snapshot is presented to indicate the influence of surface wettability on the droplet's movement and morphology. In general, as the surface becomes more hydrophobic, the droplet gains a larger overall velocity, but the deformation also influences the movement of the droplet. The droplet in the Leidenfrost stage is also investigated, and the rela-tionship between the Jakob number and droplet velocity and temperature distribution is obtained. This study aims to reveal the characteristics of the impingement between a droplet and a conical obstacle and provide fundamental support to related engineering applications such as spray cooling.