Study on the flow field structure and pulsation characteristics of liquid oxygen transient expansion directional energy release gas

WANG Yanbing; LI Xue; QUE Chaoyang; FU Dairui; HU Yizhong; MAO Huigang; LEI Zhen

doi:10.13247/j.cnki.jcumt.20250007

Abstract：To investigate the phase change expansion and flow field structural characteristics of the gas flow field during the directional energy release process of liquid oxygen transient expan-sion,a combination of high-speed schlieren test and overpressure testing system was used to conduct liquid oxygen transient phase change expansion tests under different slit widths.Sta-tistical software was used to analyze the variation characteristics of the brightness Mean and pulsation RMS values of the schlieren image,and the relationship between image grayscale and flow field density gradient was derived based on the schlieren image.The flow field pulsation laws corresponding to different stages of liquid oxygen phase change expansion were studied.At the same time,the dynamic change characteristics of the gas flow field were analyzed based on the collected and calculated velocity and overpressure field data.The research results indi-cate that the expansion process of liquid oxygen phase change can be divided into two stages:liquid oxygen escape and phase change stage,and detonation stage.In the latter stage,the pulsation of the liquid oxygen reaction gas flow is more severe than the former.The gas flow density in both stages changes dramatically along the direction of the cutting seam of the drug package.After the two stages are completed,the flow field density gradually decays to the en-vironmental density;The narrow slit channel accelerates the release rate of gas products,en-hances the local compression effect of gas,guides the directional injection of oxygen and com-bustion gas,and promotes energy concentration in the direction of the slit.As the slit width increases,the amount of gas escaping increases,and the concentration of energy released by the drug package decreases.The corresponding airflow pulsation velocity along the slit direc-tion gradually decreases;Compared to wide slit liquid oxygen charges,liquid oxygen charges with smaller slit widths effectively improve the release efficiency and control energy distribu-tion of liquid oxygen phase change products during transient phase change expansion.The con-centration of energy release determines their directional fracturing effect on rocks,and research can provide new ideas for directional rock breaking technology.