磨料水射流与磨料气体射流破岩压力对比分析

Comparison analysis on the rock breakage pressure induced by abrasive water jets and abrasive gas jets

为验证磨料气体射流破岩可行性,对比分析磨料水射流和磨料气体射流破岩效果。理论分析了磨料水射流和磨料气体射流中磨料加速机理,得出磨料动能与磨料水射流和磨料气体射流入口压力之间的数值关系。基于统一强度理论,建立了适用于磨料射流破岩的能量准则,得出了岩石破坏时所需的临界能量。根据磨料加速理论和岩石破坏临界能量计算了岩石破坏临界磨料速度以及所需入口压力。基于理论计算结果,试验验证了磨料水射流和磨料气体射流冲蚀灰岩的破碎效果。结果表明:当磨料速度达到270 m/s时,所需气体射流压力的理论值为15 MPa,水射流压力的理论值为45 MPa;两种磨料射流冲蚀坑形状相同,均呈现"V"型,磨料水射流的冲蚀坑形状相较于磨料气体射流具有"口小","坑深"的特征,磨料气体射流破灰岩形成的冲蚀坑体积要大于磨料水射流。

In order to verify the feasibility of rock breaking by abrasive gas jet,the effect of abrasive water jet and abrasive gas jet on rock breaking is compared and analyzed.In this paper,the mechanism of abrasive acceleration in abrasive water jet and abrasive gas jet is theoretically analyzed.The numerical relationship between the abrasive kinetic energy and inlet pressure of abrasive water jet and abrasive gas 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 gas jet on limestone erosion is experimentally studied.The results show that when the abrasive speed reaches 270 m/s,the required gas 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 gas 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 gas jet is larger than that of the abrasive water jet.