Lattice Boltzmann Simulation of Surface Impingement at High-Density Ratio

In this work, a novel two-phase lattice Boltzmann method has been employed to study droplet impact dynamics in the presence of a surrounding lighter phase. All the simulations were conducted in a three-dimensional Cartesian coordinate system, with the density ratio of the liquid phase to the gas phase fixed at 50. First, simulations of binary droplet collisions are conducted to validate the methodology for 20 < We < 80. Three different types of outcome, namely, coalescence collision, separating collision, and stretching collision, are presented. Secondly, the normal impact of a liquid drop impinging on a perfectly smooth dry surface is simulated at various liquid Weber and Reynolds numbers. Results are shown to compare the spread factor dependence on impact velocity, liquid density, liquid viscosity, surface tension, and surface wetting characteristics. The results are validated with experimental data. Two different outcomes are obtained: deposition and splashing breakup. The transition to splashing is found to be dependent on the liquid Weber and Reynolds numbers.