Self-excited pulsation performance and dual-cavitation synergistic mechanism of the angular Helmholtz cavitation jet nozzle

Cavitation jet, owing to its exceptional erosion capabilities, has shown considerable potential for application across petroleum engineering fields. To enhance jet performance and cavitation effects, an angular Helmholtz cavitation jet nozzle (AHCJN) based on a multi-cavitation synergistic mechanism was designed. This study investigates the dual-cavitation synergistic mechanism of the AHCJN and examines the influence of process parameters on its self-excited pulsation performance through numerical simulations. Results showed that the dual-cavitation synergistic mechanism of AHCJN is characterized by the periodic expansion and collapse of bubbles in the resonator, driving cyclic energy accumulation and release within the nozzle, while the migrated bubbles in the diffusion section induce secondary periodic energy concentration and release. The pulse peak increases linearly with injection pressure, decreases exponentially with confining pressure, exhibits an initial rise followed by a decline with standoff distance, and remains unaffected by ambient temperature. The pulse amplitude shows a linear increase with injection pressure, an exponential decrease with confining pressure and ambient temperature, and an exponential increase with standoff distance. The pulse frequency increases linearly with injection pressure and is unaffected by confining pressure, standoff distance, or ambient temperature. Additionally, a mathematical model developed using multiple linear regression (MLR) identified injection pressure as the primary factor influencing both pulse peak and frequency, with confining pressure primarily affecting pulse frequency. These key findings will provide theoretical guidance for the application of cavitation jets in petroleum engineering.