Estimation of Fire-Related Parameters in Tunnels from Analytical Modeling of Warm Advection
B. P. Kazakov, A. V. Shalimov, E. L. Grishin, D. S. Kormshchikov
Mining Institute, Ural Branch, Perm, Russia
Keywords: advection, temperature gradient, stratification, instability, depression, heat power, unsteady heat transfer, Grashof number
Abstract
The article presents the analytical research data on the convective motion dynamics and air temperature variation in a mine tunnel after cutoff of a drag source during fire. The single-valued prediction is only possible based on the stability theory of convection currents. The mathematical modeling of advection currents of counter air flows in a tunnel is performed at longitudinal gradient of temperature. The analytical formulas are obtained to calculate advection vortex and air flow velocity in vortex as function of burning time and temperature at the source. The range of hot airflow weakly depends on the burning temperature, insignificantly grows within a day and makes 850 m at the temperature of 1000 °С. The developed procedure allows evaluating the fire size and duration, as well as the air flow velocities in tunnels after the drag source cutoff.
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