High-voltage pulse fragmentation (HVPF) offers a promising approach for energy-efficient rock comminution. This study presents a combined numerical and experimental investigation of the mechanisms of electrical rock breakage in sandstone during HVPF.
Experiments were conducted to assess the influence of electrode gap, pulse count, and electrical conductivity of the ambient fluid on damage propagation.
The results show that smaller electrode gaps and an increased number of pulses lead to larger damaged volumes, with experimental damage accumulation showing an exponential trend. In contrast, numerical modeling developed in COMSOL Multiphysics predicts a linear increase in damage, attributed to simplified assumptions regarding damage evolution.
To improve agreement, a damage-dependent breakdown threshold is introduced into the model. The impact of ambient fluid conductivity is also investigated. Experimentally, a higher conductivity increases the voltage gradient required to form a discharge channel, while numerically, increased conductivity decreases the damage volume.
These results highlight the influence of fluid properties on breakdown behavior and support the development of more realistic models for the electrical fragmentation of rock.