Study on the mechanism of outlet-pressure optimization for enhancing the durability of ultra-high-pressure microjet nozzles

Abstract Ultra-high-pressure micro-jet (UHP) sterilization technology has received significant attention as a non-thermal food processing method. However, during highpressure jet operation, cavitation at the nozzle outlet rapidly damages the nozzle structure, resulting in extremely poor durability and consequently limiting the application of UHP micro-jet technology in food processing. To address this issue, this study first built a CFD model of the ultra-high-pressure jet system to simulate the spatial distribution of cavitation regions in the flow field near the nozzle. The model’s accuracy was then validated through accelerated cavitation-erosion experiments on jet nozzles. Finally, based on this model, we calculated the effects of different jet outlet pressures on cavitation distribution near the nozzle. The results show that increasing the jet outlet pressure can effectively suppress cavitation in the flow field near the nozzle, providing a simple and effective approach to improving the service life of ultra-high-pressure jet nozzles.