Effects of periodic cavitation on steam–water flow regime transition and mixing near steam nozzle exit

Abstract

Supersonic steam injection from underwater vehicles into surrounding bulk water exhibits the formation of coherent structures due to the interfacial interaction between the steam and water. The mixing between the two is a function of the rate of growth of shear layer. In present work, experimental study is conducted with minor contribution from the CFD, to highlight the phenomena associated to the high-pressure steam injection into a pool of water under the influence of periodic cavitation which occurs near the steam's nozzle exit with its opening being at right angle to the opening of the exit nozzle. PIV setup along with piezoelectric acoustic emission sensors as well as LM35 temperature sensors and pitot tubes were applied to characterize the growth of the shear layer as a function of periodic cavitation with a range of steam's operating pressure. Based on the normalized shear growth rate as well as the Strouhal number and the normalized pitot thickness, the effect of rising in the cavitation on the variations of the thickness of the shear layer was studied. It was observed that higher area under the influence of the shear layer was due to the domination of the coherent flow structures, which influenced improved mixing between the steam and water. Comparison of our data with the available shear growth rate in literature shows good agreement when compared as a function of Mach number.

Detergent Dissolution Intensification via Energy-Efficient Hydrodynamic Cavitation Reactors

“…First, the flow patterns and effects including turbulence and microjets generated in the presence of cavitation result in the enhancement of advective mass exchange of the solute to solvent, and subsequently enhances the dissolution. 41 Additionally, in a recent study, 21 it was illustrated that the energy released from the cavitation bubble collapse leads to the deagglomeration of the particle cluster, which further enhances the dissolution rate. As it was shown in our previous study as well 30 that a further increase in the upstream pressure intensifies cavitating flow while reducing the advective mass transport time.…”

“…Cavitation enhances the dissolution in two ways. First, the flow patterns and effects including turbulence and microjets generated in the presence of cavitation result in the enhancement of advective mass exchange of the solute to solvent, and subsequently enhances the dissolution . Additionally, in a recent study, it was illustrated that the energy released from the cavitation bubble collapse leads to the deagglomeration of the particle cluster, which further enhances the dissolution rate.…”