Comparison of the rock breakage pressure of abrasive water jets and abrasive air jets

Abstract

To verify the feasibility of rock breakage with abrasive air jet, the effect of abrasive water jet and abrasive air jet on rock breaking is compared and analyzed. In this paper, the mechanism of abrasive acceleration in abrasive water jet and the abrasive air jet is theoretically investigated. The numerical relationship between abrasive kinetic energy and inlet pressure of abrasive water jet and the abrasive air jet is obtained. Based on the unified strength theory, the energy criterion for rock breaking by abrasive jet is established, and the critical energy required for rock failure is obtained. Based on the accelerated theory of abrasive and the critical energy of rock failure, the critical rock velocity and the required inlet pressure of rock are calculated. Based on the theoretical calculation results, the crushing effect of abrasive water jet and abrasive air jet on limestone erosion is studied experimentally. The results show that when the abrasive speed reaches 270 m/s, the required air jet pressure theoretical value is 15 MPa, the water jet pressure theoretical value is 45 MPa. Two kinds of abrasive jet erosion pits are shaped with “V” type. Compared with the abrasive air jet, the shape of the crater of abrasive water jet has the characteristics of “small mouth” and “deep pit”. The size of the erosion crater formed by the abrasive air jet is larger than that of the abrasive water jet.