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Numerical modelling of coal mine explosion

Klemens R., Kosinski P., Wolanski P., Korobeinikov V. P., Markov V. V., Menshov I. S., Semenov I. V.

Archivum Combustionis

2001

Vol. 21 nr 1

71-79

The investigation of unsteady processes behind shock waves propagating in a gasdust combustible mixture is very important to understand mechanisms of industrial dust explosions like those in coal mines. In the paper, two aspects of this study are considered. The first one concerns questions related to ignition and burning of the mixture, where some results are given of numerical investigation of the transition to detonation process. Also 2D structure of unsteady detonation in the mixture of coal particles with air is taken into consideration. In the applied model, the moving medium is treated as a two-phase, two-velocity and two-temperature continuuum with mechanical and thermal interaction between the phases. Devolatilization, gas-gas and gas-particle exothermic chemical reactions, radiation and heat conduction are also taken into account. The other aspect is the problem of the dust enhancement and dispersion from the dust layer behind a shock wave. The forces caused by particles rotation and gas vorticity are taken additionally into account. Two numerical methods were developed to solve numerically the considered problems. Examples of calculations are presented.

On electrical discharges and ignitions of combustible mixtures

Bobrov Yu.K., Korobeinikov V.P.

Archivum Combustionis

1998

Vol. 18 nr 1-4

76-85

Mathematical methods are used for the study of electrical discharge initiation and propagation as well as ignition and extinction of different kinds combustible media. The results of mathematical theory of catastrophe, dynamical systems and finite difference approaches are applied. The critical parameters for breakdown and ignition of combustible mixtures are obtained due to the analysis. The physical nature of electrostatic sparks and linear discharges is also discussed. The basic parameters of the discharges arising near and far from walls are described. The method of mathematical theory of catastrophe is used for the study of electrical discharge formation. The gas case and two-phase mixtures of dusts with gases and solid matter case are considered. The critical values of electrostatic fields, pressures, temperatures and the particle concentrations are determined theoretically. As an example, the ignition possibility of large combustible mixture clouds in air by lighting is discussed. A comparsion with experimental data is briefly considered. The full mathematical model of electrical discharge development in the combustible mixtures is also briefly discussed.