COMPUTATIONS OF DROP DYNAMICS WITH THE IMMERSED BOUNDARY METHOD, PART 2: DROP IMPACT AND HEAT TRANSFER

Abstract

In Part 2 of the two-part article, the impact dynamics of a liquid drop on a flat surface with heat transfer is numerically simulate d with the immersed boundary method. Computations with both static and dynamic contact angles are adopted to assess the importance and implications of the modeling aspect. Both water and ink droplets are considered, with direct experimental visualization and quantitative measurement employed to assess the computation. The effects of wettability, viscosity, surface tension, and impact velocity on the droplet spreading and recoiling behavior and wall heat transfer are assessed. It is found that the drop inertia directly influences the spread characteristics, the surface tension plays a major role in the recoil frequency, the drop viscosity damps out the drop spread and recoil, and the contact angle affects both the spreading and recoiling processes. Overall, the dynamic contact angle model attenuates the recoiling of the drop. The wall heat flux distribution is clearly affected by the drop dynamics. Larger spreading results in a wider area of heat exchange. High heat flux rates take place at the early stage of impingement and decays in time.