Mining Institute, Ural Branch, Russian Academy of Sciences (Perm, Russia)

A. V. Shalimov, Leading Researcher, Doctor of Engineering Sciences
S. Ya. Zhikharev, Chief Researcher, Doctor of Engineering Sciences, Associate Professor
M. A. Semin, Head of Laboratory, Doctor of Engineering Sciences
D. S. Kormshchikov, Senior Researcher, Candidate of Engineering Sciences
E. G. Kuzminykh, Engineer, kuzminykh.evgeniy@gmail.com

The article presents the results of a comprehensive study of the stability of mine workings ventilation during mine fires based on three methods of modeling mine aerological processes – analytical, numerical and physical. In the Boussinesq approximation, the magnitude of the critical vertical gradient of air temperature in the supply shaft during the cold season is analytically determined, at which the column of air in it loses stability with the appearance of return flows. Based on the results of calculating the heat exchange of air with the shaft support at different speeds of its movement, it was concluded that there is a minimum speed at which natural thrust in a mine with single-level shafts ceases to support itself, and in the emergency zero ventilation mode, the mine ventilation stops, which is the purpose of turning off the fan in case of fire. Based on numerical modeling, another approach to determining the convective stability of air by the magnitude of the adiabatic gradient, adopted in meteorological studies of atmospheric processes, is analyzed, giving a more rigorous forecast, according to which the critical temperature gradient is almost 4 times less than that obtained by the first method. It has been established that the cramped conditions of mine shafts have a strong stabilizing effect on air stability, corresponding to a greater extent to the analytical scenario of its loss. A low-temperature scaling method has been developed as a theoretical justification for laboratory experimental studies of air movement along inclined mine workings during a fire. It is shown that this method can be useful in creating physical models of such workings with a heat source, when the generally accepted method of Froude scaling is not applicable due to the impossibility of conducting high-temperature experiments in laboratory conditions.
The research was funded by the Russian Science Foundation under project No. 26–19–00270.

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