A phase-diagram-formulated EOS and fluid-solid coupling analysis for eco-friendly blasting of carbon dioxide phase transition

The Carbon dioxide (CO2) phase transition blasting is a state-of-the-art technology in fields of geotechnical, geological, and mining engineering, due to its advantages of high safety, environmental friendliness (Non-toxic and smoke-free), and cost-effective design benefited from the low-temperature characteristics. However, the evolution mechanism of CO2 within the pressure vessel before the blasting is still not clearly revealed. To address this issue, a phase-diagram-formulated Equation of State (EOS) is proposed to describe the phase evolution and mechanical behaviors of CO2. Furthermore, a fluid-solid coupling simulation model is established using the Euler grid-based Finite Element Method (FEM). The simulation model is validated through CO2 phase transition blasting experiments and then used for the mechanism analysis. The results reveal that the initial rapid rise, further slow increase, and extremely rapid decline of the pressure evolution in the vessel are dominated by the combination of heat absorption and external work, the phase transition of CO2, and the failure of the rupture disc, respectively. In addition, the influence laws of combustion agent energy, environment temperature and rupture disc strength on the blasting are systematically investigated. The final conclusions may provide useful insights for the design of CO2 phase transition blasting and the development of eco-friendly blasting technologies.