Experimental characterization and analysis of supercritical jet dynamics by phase-shifting interferometer system

The dynamics of trans-/super-critical jet significantly influence system behaviors for applications in spray and combustion, power conversion and chemical reactions. In this study, a pixelated phase-shifting interferometer with high spatial and temporal resolution has been established to investigate the quantitative characteristics of the sub-/trans-/super-critical jets. Thermodynamic features of the jets have been revealed through the transient quantitative field data. Theoretical analysis through experimental results on density and its gradient data has been elaborated. Boundary fractal analysis and radial diffusion process are examined with parameters of mixing layer thickness and spreading rate. The radial distance of the maximum density gradient decreases with time, which indicates jet transition from liquid to supercritical state as approaching the dense core. The fractal dimension of the edge varies from 1.30 to 1.38 for liquid-into-supercritical jet, showing that the initial “liquid” dominated feature and gradually transform process to a supercritical state from the mixing layer.