Predictive modelling of nucleate boiling in impacting droplets for high heat flux spray cooling applications

This project seeks to overcome current obstacles to predictive modelling of nucleate boiling in droplets impacting on realistic non-uniform heated surfaces. The key development will be a novel coupling of a mesoscopic lattice Boltzmann method, capable of capturing the incipience of boiling without artificial seed bubbles, together with OpenFOAM-based Navier-Stokes simulations of macroscopic droplet dynamics. This is important for improving and optimising spray cooling of high heat flux surfaces. The project is a collaboration with two US partner universities, where validation experiments will be conducted. Key questions that we wish to answer using the new capability include: (i) What triggers nucleation during droplet impact? (ii) How do impact conditions affect nucleation, boiling and heat transfer? (iii) How do surface conditions and topography affect nucleation, boiling heat transfer? (iv) What are the physical limits to boiling in droplets? The investigation will create new highly publishable droplet impact and boiling regime maps and contribute to understanding the influence of droplet and surface thermophysical properties as well as surface roughness effects.