A new calculation formula to describe the dynamic pressure of water jet peening with elliptical nozzle for high-efficiency treatment

Abstract

Water jet peening is a good potential method to control welding residual stresses. The water jet with elliptical nozzle can improve the treatment efficiency due to its large treatment area. In this article, the water jet velocity and dynamic pressure for different elliptical nozzle dimensions and standoff distances are discussed by numerical simulation. The results show that when the axial distance is 10 mm, the effective impact diameter of the elliptical nozzle a/b=8–12 is about 2 times or more than that of the circular nozzle. The length of the jet core of the elliptical nozzle is only related to the outlet structure and is independent of the inlet pressure. The correlation between the dimensionless core length of the elliptical water jet and its long and short axes is derived. When the ratio of the major axis to the minor axis is between 7 and 13, the core length of the elliptical water jet is 7–7.5 times that of its minor axis. Combining the suitable treatment area and dynamic pressure, the elliptical nozzle with an axis ratio of 8 is recommended to control the welding residual stress. Finally, a new formula for calculating dynamic pressure distribution is proposed for the elliptical nozzle water jet at different stages.

Effect of Special-Shaped Nozzle Structure on Water Jet Performance

“…Water is used in water jet technology as the working medium to produce high-speed jet beams by using specifically shaped nozzles with extremely high energy [1][2][3]. It is widely used in machining, coal mining, petroleum exploration, aerospace, medical surgery, equipment cleaning, and many other fields due to its clean, nonthermal effect, ease of control, high efficiency, safe and convenient operation, and other advantages [4][5][6]. As the core component of water jet technology, the structural parameters of the nozzle directly affect water jet performance.…”