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Diffusion principles of SF6 tracer gas: constraints on SF6 mixing distance in mine tunnels

Year: 2025
Type: article
Abstract: Mine wind measurement work is an important task to ensure the normal operation of mine production and environmental safety. The traditional wind measurement method uses the average wind speed and average cross-sectional area of the tunnel to calculate the air volume. Due to the fact that the tracer gas wind measurement method does not require the measurement of average wind speed and tunnel cross-sectional area, the error is smaller than traditional wind measurement methods. The wind measurement method monitors SF 6 diffusion by stably releasing SF 6 in the tunnel, and then measuring the SF 6 concentration until achieving even distribution. The accuracy of SF 6 concentration measurement directly determines the accuracy of wind measurement. The premise of accurately measuring the uniform concentration of SF 6 distribution is to determine the SF 6 mixing distance. This study analyzes the diffusion principles of SF 6 in the tunnel, and applies the computational fluid dynamics method for three intersecting tunnels to study the SF 6 -air mixing distance in the intersection tunnel under a range of conditions to assess the effects of various parameters on the SF 6 mixing distance. The SF 6 concentration distribution was investigated to determine the optimal location for concentration sensors. The results indicate that the SF 6 mixing distance increases with gravity, while the SF 6 concentration distribution rectangular and semi-circular arch tunnels follows a relationship of left and right interchangeability. For a given cross-sectional shape, shorter mixing distances are associated with larger tunnel cross-sectional areas, lower SF 6 concentrations, higher tunnel wind speeds, and greater angles between the two air inlet tunnels. The results of this study provide a reference for selecting appropriate numerical simulation models for more accurate mine wind measurement work and future intelligent ventilation wind measurement.
DOI: 10.1038/s41598-025-86864-5
Language: English
Open Access status: gold
Estimated APC paid: $2,690
OpenAlex ID: W4408963594
FWCI: 1.738
Cites: 17
Cited by: 3
Related to: 10