Physical and Chemical Geotechnologies

Purpose

To establish the regularities of the process of heat release into the methane-air mixture through redhot friction particles formation during the destruction of the gas-saturated rock by working elements of shearers and tunneling machines.

Methodology

We have applied the analytical method of research involving the following: Newton-Richman’s law, the density of the heat flowing into surrounding environment from the surface of a moving hot friction particle is proportional to the temperature difference between the surface of the friction particle and surrounding methane-air mixture; Fourier’s law about the intensity of heat transfer by heated objects into the environment; criterion equation describing the accumulated heat rejection process under forced convection. We have designed the mathematical model of formalized description of the process of heat transfer into the surrounding dust-methane-air medium by moving cloud of frictional sparks.

Findings

We have obtained the dependencies for determining the amount of accumulated heat and heat transferred by a friction particle to into the surrounding methaneair medium, and calculation of the time spent on heat transfer into the combustible mixture, allowing taking into account the induction properties of methane-air medium. We have developed and theoretically substantiated the formal mathematical model describing the process of heat transfer into the surrounding methane-air medium by the moving cloud of frictional sparks formed as a result of interaction of the cutting tool of the working body of the shearer with gas-saturated rock. It differs from the existing as it takes into account the induction properties of methane-air medium and allows determining of the range of dangerous levels of thermal parameters capable for the combustible mixture ignition. We have determined the effective measures and means to prevent explosions methane-air mixtures. We have suggested the criterion of methane ignition safety. It allows evaluating the effect of frictional sparking on the ignition of dust-methane-air mixture and determining the level of danger during the gas-saturated rock destruction by cutting tool of the working body of the combine.

They contain the researches, which were conducted within the project GP – 489, financed by Ministry of Education and Science of Ukraine.

Keywords: friction particle, heat flow, methane-air medium, dust-methane-air mixture inflammation, cutting tool

References

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