Improvement of abrasive jet efficiency in cutting operations

The paper deals with the results obtained in the frame of a research programme aimed at increasing the cutting performance of plain and abrasive waterjet through the improvement of the jet structure and of the process of energy transfer. The features of plain jets have been investigated at variable experimental conditions (nozzle diameter, stand-off distance and pressure) using different techniques. Concerning abrasive jets, the structure of which is destroyed by the presence of solid particles and of entrained air (in the case of AWJ experiments), the improvement achieved has been directly evaluated on the basis of cutting results. The advantage of polymers addition due to their stabilising effect on the turbulence produced by the high velocity flow of the water along the pipe and the nozzle is put into evidence.