Dynamic pressure enhancement upon disk impact on a boiling liquid

TL;DR

This study experimentally examines how a disk impacting boiling liquid causes unexpectedly high pressures due to vapor pocket collapse, relevant for cryogenic fuel safety.

Contribution

It reveals the mechanism of pressure enhancement during impact on boiling liquids, highlighting vapor condensation effects not previously characterized.

Findings

High impact pressures deviate from inertial scaling.

Rapid vapor pocket collapse occurs at high impact velocities.

Vapor condensation accelerates vapor pocket contraction.

Abstract

We experimentally investigate the impact of a flat, horizontal disk onto a boiling liquid, i.e., a liquid in thermal equilibrium with its vapor phase. We observe exceptionally high impact pressures deviating strongly from the inertial scaling found for impact in a non-condensable environment, coinciding with the rapid collapse of the vapor pocket entrapped below the disk. We explain our findings, which are relevant for the safe transportation of cryogenic fuels, as a result of vapor condensation, leading to accelerated vapor pocket contraction at high impact velocity and low vapor density.