Numerical Study of the Diffusion Law of Buried Natural Gas Pipeline Leakage between Buildings

Abstract When a buried natural gas pipeline leaks, different factors will have an impact on the diffusion of natural gas leakage. Previous studies mostly took single-source leakage in pipelines as the background. This study took the dual-source leakage of a buried natural gas pipeline between two buildings as the background; analyzed the variation laws of the velocity, streamline, and concentration of the leaked natural gas in the soil–atmosphere coupled space; and studied the influence of different soil environments, pipeline leakage states, surface wind speeds, and building layouts on the ground diffusion boundary of single- and dual-source leakage of buried natural gas pipelines. The results show that an increase in soil porosity and particle size leads to an increase in the early warning boundary. Hardening the ground and increasing pipeline pressure will cause the early warning boundary of ground natural gas to increase, whereas the burial depth of the pipeline has little effect on the early warning and the dangerous boundaries. The different heights of the two buildings will reduce the range of the ground natural gas early warning boundary and the danger boundary, and the decrease in surface wind speed will lead to an increase in the range of the natural gas early warning boundary and the dangerous boundary. The early warning boundary and danger boundary prediction models for single- and dual-source leakage of buried natural gas pipelines between two buildings were established by simulation calculation. The average errors between the single-source leakage prediction results and the simulation results were 1.5% and 14.7% respectively, and the average errors between the dual-source leakage prediction results and the simulation results were 4.0% and 9.6% respectively.