Cavitating flow morphology determination in cavitation-on-a-chip devices based on local real-time pressure measurements

This study presents a practical approach for the characterization and control of hydrodynamic cavitation (HC) behavior in microfluidic devices by utilizing real-time static pressure measurements. Two geometrically identical micro-orifice devices were specifically designed for this purpose. Pressure measurement locations were strategically positioned along the embedded microchannel in both devices. These locations were determined as a function of the hydraulic diameter of the microchannel. Pressure measurements were simultaneously made with high-speed imaging. Particular attention was directed to the prediction and monitoring of cavitation inception, cavitating flow patterns, and cavitation development. Thus, the dynamic and complex nature of hydrodynamic cavitation in microdomains could be captured by local pressure variations along the microchannel walls. According to the results, cavitation inception and subsequent formation of twin sheet cavities could be detected by changes in local pressure values. Moreover, the analysis of local pressure variations could be employed to predict the length of sheet cavities. The findings of this study offer valuable guidelines for designing microfluidic systems involving hydrodynamic cavitation. Moreover, this study proves the potential of local wall pressure measurements as a stand-alone practical approach, which will reduce reliance on high-speed visualization. It could thus enhance the affordability and accessibility of HC-on-a-chip platforms for emerging applications, including biomedical engineering, wastewater treatment, and 2D material exfoliation.