Mechanism of transient phase transition in liquid oxygen with different absorbent media

This study captures transient phase change reaction images of dual liquid oxygen charges with different absorbent media in the same frame using a high-speed camera. Based on grayscale image temporal features, the transient phase change reaction process of liquid oxygen charges with different media is divided into three stages: initial combustion, gasification expansion, and turbulent dissipation. By inverting the relative velocity and temperature fields from grayscale images, the differences in phase change processes among various absorbent media are analyzed, exploring the characteristic differences of absorbent media with different fiber structures across reaction stages. The study reveals that tissue paper, as a porous short-fiber material, releases energy steadily, while cotton, with its dense long-fiber structure, exhibits concentrated energy release with a longer time delay due to lower permeability. Under identical initiation times, tissue paper shows a more uniform reaction velocity distribution compared to cotton, which produces transient high-speed points. The phase change uniformity of tissue paper is significantly higher than that of cotton, indicating that the short-fiber structure of tissue paper has a superior liquid oxygen adsorption capacity compared to cotton. Although cotton generates higher local pressure, the uneven adsorption of liquid oxygen leads to a significantly lower energy utilization efficiency and non-uniform energy release. As a potential indicator reflecting rock-breaking performance, this difference in energy utilization demonstrates that the liquid oxygen charge with cotton as the absorbent media exhibits inferior potential rock-breaking performance compared to that using toilet paper as the absorbent media. • Innovation in Observation Technology: A high-speed camera is used to capture transient phase change reaction images of dual liquid oxygen charges with different absorbent media in the same frame, enabling synchronous visual observation of phase change processes under multiple working conditions. • Division of Process Stages: Based on the temporal features of grayscale images, the transient phase change reaction process of liquid oxygen charges with different media is clearly divided into three stages: initial combustion, gasification expansion, and turbulent dissipation, providing a clear framework for phase change mechanism analysis. • Multi-Physical Field Inversion and Analysis: By inverting the relative velocity and temperature fields from grayscale images, the differences in phase change processes among various absorbent media are systematically analyzed, and the characteristic differences of absorbent media with different fiber structures across reaction stages are explored. • Revelation of Medium Structure-Performance Relationship: The mechanism of performance differences between two typical absorbent media is clarified—tissue paper (porous short-fiber material) exhibits steady energy release, uniform reaction velocity distribution, high phase change uniformity, and superior liquid oxygen adsorption capacity; while cotton (dense long-fiber material) shows concentrated energy release with a longer time delay due to lower permeability, prone to generating transient high-speed points. Although cotton produces higher local pressure, its uneven adsorption leads to low energy utilization efficiency and non-uniform energy release. • Verification of Application Performance: It is confirmed that in the application of absorbent media for liquid oxygen charges, the rock-breaking performance of tissue paper is superior to that of cotton, providing experimental and theoretical basis for the selection of absorbent media for liquid oxygen charges.