Erosion characteristics of pulsed waterjets issuing from a novel ultrasonic nozzle

By taking advantage of the stress wave effect, pulsed waterjet has higher working efficiency when used in mining, cleaning, and surface treatment. To clarify the erosion performance of our newly designed ultrasonic pulsed waterjet (UPWJ), effects of the ultrasonic power and erosion time were experimentally studied and compared with a continuous waterjet (CWJ). Homogeneous material 6061 aluminum alloy suitable for evaluating the erosion performance of waterjet was used as specimen. The erosion morphology, surface parameters, and material removal rate were used to evaluate the performance. Results show that ultrasonic power and erosion time have a positive effect on the erosion capacity of UPWJ, and the erosion edge was more rounded, with the center showing an erosive layer owing to the water hammer effect. Compared with CWJ, the erosion depth of UPWJ was significantly increased by 34% at 450 W and 3 min, while the erosion area is hardly enlarged, meaning that UPWJ has a higher energy density. Moreover, the roughness of erosion pit of UPWJ is generally larger, and the uniformity of the erosion surface is better. The material removal rate of UPWJ is pronouncedly larger than that of CWJ, with a maximum enhancement of 76% at 450 W and 2 min. Besides, the specific energy consumption of UPWJ is up to 20% lower, showing that UPWJ has a higher energy efficiency.