Lagrangian Approach for Simulating Supercooled Large Droplets’ Impingement Effect

In this paper, a droplet tracking method and a splashing model have been developed to calculate the droplet collection efficiency in a supercooled-large-droplets regime using the Lagrangian computational method. In the droplet tracking method, the droplet deformation and the droplet-wall effects (for example, splashing, bouncing, and reimpingement), which are the typical cases in a supercooled-large-droplets regime, are incorporated by introducing the mass residual ratio. The effects of the transition from the conventional-small-droplets impingement to a supercooled-large-droplets impingement, as well as the splashed secondary droplets, on the droplet collection are considered in the current splashing model. The performance and capacities of the droplet tracking method and the supercooled-large-droplets splashing model are validated against the alternative experimental reference data. The mass loss ratio and the mass back ratio are introduced in order to explore the distribution and the quantity of the mass loss and mass back caused by droplet splashing and reimpingement. The predicted results show that the quantity and the distribution range of the mass back ratio on airfoil surfaces are relatively lower than those of the mass loss ratio. A significant mass back is observed when the airfoil is contaminated with ice. No mass loss or mass back is observed beyond the impinging region for the given conditions.