Water aerosol formation: Transient process induced by shock waves

Abstract

The formation of aerosols artificially is an interesting topic nowadays. This paper studied the interaction between water sheets and shock waves experimentally to seek the interaction mechanism and simulate the formation processes of water aerosol. Optical instruments like normal high speed camera and multiple-spark high speed camera were employed in the experiments and the data obtained was solved with common statistics software Statistical Product and Service Solutions (SPSS). Phase Doppler Particle Analyzer (PDPA) was also used to give a description of the water aerosol shown with diameter and velocity parameters. After the analysis of typical photos and data obtained, results showed that once past through by shock waves, the water sheet faced a surface stripping and breaking progress. The shock-wave induced in the layer of water is a compressive elastic-wave, whose magnitude is related to the ratio of acoustic impedance of the two media. Shock propagates through the thickness of the water-wall and when it reaches the next water/air interface is nearly totally reflected as a tensile wave. Such tensile wave will induce cavitation in the water-wall. Subsequent to cavitation, water keeps moving with uniform velocity and undergoes tensile strain, with small vapor bubbles forming while the water keeps moving in the direction of the blast. Finally, based on the dispersal mechanism, dimensionless parameters calculated were brought in to build the water dispersal model.