Investigations on main hydraulic parameters of a new abrasive water jets assisted bit for rock drilling

To abrasive water jets (AWJ) assisted bit for rock drilling, the penetration speed efficiency can be effected by three main hydraulic parameters of AWJ, namely nozzle diameter, jet pressure and abrasive concentration. By theoretically analyzing, equation for the relationship between penetration speed and main hydraulic parameters was established. The AWJ drilling experiment within limestone was carried out as well. Results obtained from theoretical and experimental ways indicated that nuzzle diameter was the most important effect factor to penetration speed, which was followed by jet pressure and abrasive concentration orderly. Convenient calculation formula of penetration was derived from regression analysis of experimental data. The achievements of present study provide reference evidences for drilling speed of this new abrasive water jets bit.