Experimental study on the non-equilibrium condensation of a liquid film after shock wave in a vertical diaphragmless shock tube

Abstract

In this study, the physical characteristics of ethanol vapor behind the incident and reflected shock waves in a vertical diaphragmless shock tube are measured. To verify the excellent properties of the vertical diaphragmless shock tube, the experimental data are compared with the theoretical Rankine-Hugoniot curves. Combined with the shock wave visualization imaging, it is verified that the designed shock tube can be effectively used for investigating the phase-change heat transfer behind the shock waves. According to measurements based on a He–Ne laser beam optical interference system, the growth rate of the liquid film behind the reflected shock wave (Vfr) is smaller than that behind the incident shock wave (Vfi). The experimental value of condensation parameter is approximately 0.025, which is in good agreement with the theoretical value determined using the molecular dynamics approach. When the Mach number of the incident shock wave (Mi) is employed as a factor influencing liquid film growth, it is observed that when all the other parameters remain constant, the larger the Mi, the faster the growth of condensed liquid film. The vertical diaphragmless shock tube facilitates strong reproducibility of results under the same conditions, which can increase the accuracy of experiments such as phase-change heat transfer.