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The effective diffusion coefficients in mine ventilation-flows had been obtained as 4 to 200 m~2/s by matching the measured concentration-time curves with the advec- tion-diffusion equation.The turbulent diffusion coefficients in the simple airways have good agreement with the equation proposed by Taylor.However,for complex airways in operat- ing mines,the evaluated effective diffusion coefficients in the mines show higher values than that calculated by the Taylor’s equation.A numerical simulation model using with movements of discrete particles dosed into ventilation flows has been developed to simu- late diffusion phenomena of gas or dust in mine airways.Numerical simulations had been conducted on distribution of tracers in single airways with ordinary profiles of mean velocity velocity fluctuations and Reynolds stress.As one of results,long band of diffused particles is obtained at the single airway of 600 m in length,and large effective diffusion coefficient is evaluated as 20 m~2/s.
The effective diffusion coefficients in mine ventilation-flows had been obtained as 4 to 200 m ~ 2 / s by matching the measured concentration-time curves with the advecation-diffusion equation. Turbulent diffusion coefficients in the simple airways have good agreement with the equation proposed by Taylor. Even, for complex airways in operat ing mines, the effective diffusion coefficients in the mines show higher values than that calculated by the Taylor’s equation. A numerical simulation model using with movements of discrete particles, has been to simu- late diffusion phenomena of gas or dust in mine airways. Numerical simulations had been conducted on distribution of tracers in single airways with ordinary profiles of mean velocity velocity fluctuations and Reynolds stress. one of results, long band of diffused particles is obtained at the single airway of 600 m in length, and large effective diffusion coefficient is evaluated as 20 m ~ 2 / s.