Investigation of the effects of liquid medium and electrical parameters on hydraulic-electric pulsed discharge rock-breaking

The hydraulic-electric pulsed discharge (HEPD) rock-breaking technology can generate plasma channels in liquid media and shock waves from the plasma channels to break rocks. Since the HEPD rock-breaking technology involves a multi-physical field coupling rock-breaking mechanism that is difficult to describe, the theoretical modeling of this technology is less studied. In this paper, we analyze the HEPD rock-breaking process by combining numerical models and experiments and establish a multi-physics numerical HEPD simulation model, which realizes the whole process of HPED rock-breaking from the five-field coupling. The obtained numerical simulations and indoor experiments show that the HEPD process is divided into three phases: the breakdown channel formation phase, the plasma channel formation phase, and the plasma shockwave bursting phase. With the increase of liquid medium conductivity, the rock’s maximum penetration depth decreases, the rock’s maximum damage depth increases, and the trend of rock crushing pits appears to decrease. The larger the liquid medium breakdown energy consumption, the faster the electric breakdown in the liquid medium is generated, which reduces the breakdown delay. When the liquid medium conductivity increases from 0.0125 to 5 S/m, the liquid medium breakdown energy consumption increases by 13.87% and the breakdown delay decreases by 13.74%.