Similarity Criteria for Scale Modeling of Mine Fires in Inclined Underground Openings
A. V. Shalimov, S. Ya. Zhikharev, M. A. Semin
Mining Institute, Ural Branch, Russian Academy of Sciences, Perm, Russia
Keywords: Thermal depression, aerodynamic drag, energy dissipation, stratification, dimensional analysis, scaling, self-similarity, zero ventilation mode
Abstract
Scale modeling is essential in studying underground mine fires since large-scale experimentation is impossible because of unsafety while numerical modeling has limited accuracy and features high computational input. This article addresses an understudied issue of selection and substantiation of similarity criteria for the analysis of mine fires. The review of the current methods available for scale modeling of heat convection of air under high temperature differences on the basis of investigations of fires in buildings and tunnels displays their insufficient conformity with mine conditions owing to difference in geometry and in air flow behavior. The dimensional analysis reveals that similarity in laboratory modeling is achievable through observance of equality of the dimensionless Richardson, Euler and Froude numbers. The authors describe an emergency scenario, with switching-off of fans, when the only defining criterion is the Grashof number. The proposed approach makes it possible to design low-temperature lab-scale experiments to model air flow along mine openings during fire.
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