On the Energy Efficiency Under the Coupling Effect of Electric and Hydroelectric Fragmentation

The fragmentation mode of plasma-pulse geo-drilling (PPGD) is crucial to determine its energy efficiency; however, the coupling effect of the two fragmentation modes is neglected in this article, which leads to the limited improvement of the rate of penetration (ROP) of PPGD. In this article, the “pin-pin” electrode configuration is used to establish the electric breakdown model, in which we utilized the proportional coefficient of electric fragmentation (PCEF) to define the degree of coupling. To quantify this effect, we investigated the impact of the PCEF on the energy consumption efficiency (ECE) and the shock wave pressure. Additionally, we investigated the influence of circuit parameters, rock types, and coupling degree on the breakdown delay, and peak shock wave pressure of PPGD. Research indicates that: 1) the PCEF can be roughly determined by measuring the voltage breakdown delay of the “pin-pin” electrode configuration; 2) the peak pressure of the shock wave generated in dielectric (rock and liquid medium) is negatively correlated with the circuit inductance; as the capacitance increases, the ECE at the load terminal decreases gradually; and 3) the ECE at the load terminal and breakdown delay are positively correlated with the resistance coefficients of the rocks. This article is expected to provide theoretical guidance and reference for improving the efficiency of PPGD in practical engineering.