Numerical analysis of multi-factors effects on the leakage and gas diffusion of gas drainage pipeline in underground coal mines

Gas drainage system is a critical technique to prevent gas outbursts in the underground coal mine. The leakage of gas drainage pipelines can pose serious threats to the safety production of underground mining. In this paper, a multi-factors gas drainage pipeline leakage and diffusion (GDPLD) model is proposed based on the OpenFOAM platform, which can analyze the leakage and diffusion characteristics inside the pipelines. With field measurement data in a coal mine, the GDPLD model is verified with good practicability. Furthermore, scenario analysis in the context of different leak sizes, locations, and pipeline diameters is presented to evaluate the specific characteristics of gas leakage and diffusion inside the pipeline with negative pressure. The results showed that the leakage accident close to the pump station with a large leak size and small pipeline diameter usually represents the worst case, and when gas sensors are installed downstream of the leakage location, it is helpful to realize effective detection of the leakage accident. This study can help to improve the understanding of the leakage and diffusion characteristics of gas drainage pipelines and provide technical supports for the monitoring system design of the gas drainage pipelines in underground coal mines.