Numerical simulation analysis and parameter optimization of pulsed laser rock breaking

Pulsed laser rock-breaking, as a novel and efficient rock fragmentation technology, contributes to enhancing the development efficiency of ultra-hard and ultra-deep oil and gas resources. However, current research on parameter optimization analysis for laser rock-breaking remains limited. Therefore, the parameter optimization of pulse laser rock-breaking was investigated through numerical simulation and multi-objective algorithms. A Gaussian-distributed laser heat source model was established, and numerical simulations of laser irradiation on granite were conducted. The results demonstrated that increasing laser power, pulse repetition frequency, and pulse duty cycle, while reducing the beam spot radius, could enhance perforation dimensions while simultaneously reducing specific energy (SE) and improving rate of penetration (ROP). However, increasing the laser irradiation time reduced SE while simultaneously decreasing the ROP. To balance SE reduction with ROP improvement, an Improved Multi-Objective Particle Swarm Optimization (IMOPSO) algorithm incorporating adaptive t-distribution mutation and cosine-decline inertia weight (CDIW) was proposed. The results demonstrated that the IMOPSO algorithm achieved the most extensive and uniformly distributed Pareto front coverage in terms of SE and ROP ranges, ultimately yielding optimal sets of parameter combinations. The findings provide operational guidelines for laser parameter configuration in engineering applications.