PhD Defence Bernardo Palacios Muñiz | Impact of a Boiling Liquid: Droplets and Breaking Waves at Thermal Equilibrium

Impact of a Boiling Liquid: Droplets and Breaking Waves at Thermal Equilibrium

Bernardo Palacios Muñiz is a PhD student in the Department Physics of Fluids. Promotors are prof.dr. R.M. van der Meer and prof.dr. D. Lohse from the Faculty of Science & Technology.

During the transport of cryogenic fuels, such as liquid natural gas, the liquid fuel is surrounded by its own vapour in thermal equilibrium. In such conditions, minute exchanges of energy can trigger phase change, making the physics surrounding liquid impact phenomena extremely complex. In consequence, the prediction of loads, due to liquid impact on the walls of the container, is simply impossible with currently available tools. This thesis is an experimental study of fundamental solid-liquid impact phenomena, when the liquid is surrounded and in thermal equilibrium with its own vapour, i.e., when it is what we call a boiling liquid. Using high speed photography, state-of-the-art sensors and novel imaging techniques, we have performed an exhaustive campaign of two fundamental experiments at very different scales, namely of the impact of droplets and breaking waves over solid surfaces, while in boiling liquid conditions. During our research, we have found that phase change, along with other complex phenomena, plays a crucial role in liquid-solid impact:  such as suppressing the entrapment of vapour underneath a droplet or, on a much larger scale, driving large pressures due to the collapse of the vapour pocket between a breaking wave and a wall. The work on this thesis, not only aims to expand our understanding of impact phenomena by introducing phase change, but also to improve the understanding behind the loads that cryogenic fuel tanks are subjected to.