Study of Droplet Shadow Zone of Aircraft Wing with Diffusion Effects

Abstract

The aircraft deicing and detection tasks are complicated by the revealed existence of a shadow zone behind the wings, which contains no droplets due to the wing shielding effect. The effects of this so-called droplet shadow zone on the droplet distribution along the cylinder and the wing are theoretically and experimentally explored in this study. The computational domain of droplet motion is subdivided into a droplet flow zone and a droplet shadow zone. The interface between the two zones is captured by the level set method. The content of liquid water in the droplet shadow zone is zero. Outside the droplet shadow zone, the droplet trajectories are predicted using the Eulerian two-phase flow model. Fick’s law of diffusion is introduced into the Eulerian and level set equations. On this basis, a method for capturing the droplet trajectories and interface with an account of the diffusion effect is proposed. Besides, a series of experiments is carried out in the icing wind tunnel of Nanjing University of Aeronautics and Astronautics. The calculation and experimental results indicate that the proposed method can accurately predict the droplet shadow, and the calculated values of droplet collection coefficient also agree well with the experimental ones.