ABSTRACT
Improving the performance of high-speed water jets is necessary for extending their use in mining and underground applications. From the analysis of the impact of a water jet on the material surface one can show that pulsed jets provide an effective method for cutting or fragmentation of hard and brittle materials. Modulation of the continuous high-speed jet represents one of the most promising methods for generating pulsed jets. In this paper, a brief summary of theoretical models, which attempt to describe the behaviour of the modulated jet after leaving the nozzle, is presented followed by some aspects of the ultrasonic modulation of high-speed continuous water jets. Preliminary tests to evaluate the effectiveness of modulated water jets were performed using aluminum, copper and cast iron samples. The jet was modulated by the vibrations of a piezoelectric transducer and velocity transformer (horn) at 15 kHz.
