Experimental and Numerical Prediction Model for the Dangerous Radius of Natural Gas Leakage in Soil

[Image: see text] Prediction of the dangerous radius of natural gas plays an important role in reducing the hazards of a buried natural gas pipeline after leakage. The factors affecting the diffusion law of natural gas in soil after leakage are mainly divided into the pipe, soil, and environmental sides. Previous studies focused on the effects of leakage pressure, leakage aperture, and leakage direction on the pipe side and porosity and water content on the soil side. In this paper, experiments and numerical simulations are conducted for further investigating the effects on the diffusion of natural gas in soil of the soil type (porosity and granule diameter) and layered structure among the soil side factors and soil temperature as environmental side factors. The contour radius corresponding to 5% volume concentration (the lower limit of natural gas explosion in soil) is defined as the natural gas dangerous radius for analysis. Based on comprehensive analysis of the effects of the factors, a prediction model is proposed for the dangerous radius of natural gas in soil with leakage pressure, leakage aperture, porosity, and granule diameter as the dominant influencing factors, which is of great significance for locating the source of the leakage.