Does Cavitation Affect Droplet Breakup in High-Pressure Homogenization? Insights into Local Effects

Abstract

High-pressure homogenization is a popular method to produce emulsions of droplet sizes smaller than 1 µm. Regarding the role of cavitation in the process, it is still discussed controversially whether it promotes or hinders droplet breakup during high-pressure homogenization. In this study droplet breakup in a cavitating flow of an optically accessible high-pressure homogenizer orifice is visualized using a high-speed camera setup. The cavitation regime is characterized using laser light induced luminescence. Droplet deformation and breakup events are compared to a cavitation-free flow with the same specific energy input. Once the jet cavitation regime is reached, droplet breakup took place further downstream the orifice exit, and the larger droplets are measured in the final product.