Influencing mechanism of the non-isothermal behavior of an isolated vapor bubble in liquid oxygen

Abstract

The investigation of the evolution of the cryogenic gas–liquid interface is crucial for the storage and management of cryogenic propellants in on-orbit tanks. Studying the non-isothermal growth of isolated bubbles under normal gravity provides a foundation for understanding the distribution of the cryogenic gas–liquid interface. However, a low boiling point, low surface tension coefficient, and low viscosity lead to bubble behaviors that differ from those of room-temperature liquids, increasing the difficulties in investigating cryogenic behaviors, and the related studies are limited. In this work, a visualization experimental platform for liquid oxygen single bubble pool boiling was established. Liquid oxygen was produced by cooling oxygen with liquid nitrogen, and an optical visualization system was designed to observe bubble behavior. The effects of wall superheat, liquid subcooling, and pressure on bubble growth rate and detachment parameters were investigated. Results indicate that higher wall superheat reduces the waiting time for bubble growth, shortens the bubble growth cycle, and increases the bubble diameter. During the initial growth stage, the bubble diameter follows a $D\sim t^{1/2}$ trend, transitioning to $D\sim t^{1/3}$ in the later stage. Bubble growth slows with increasing liquid subcooling, while higher pressure leads to smaller detachment diameters and higher detachment frequencies. The findings compensate for the scarcity of data on the growth of isolated bubbles in cryogenic liquids, and provide important guidance for the development of on-orbit storage and transport technology.