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ASYMPTOTIC ANALYSIS OF THE COAL SELF-HEATING MODEL.
OPPORTUNITIES FOR FIRE SAFETY E.P.
Feldman*1, N.O. Kalugina1, O.V. Chesnokova1 1Institute for
Physics of Mining Processes of the National Academy of Sciences of Ukraine,
Dnipro, Ukraine *Corresponding author: edward.feldman.40@gmail.com Physical and technical problems of mining
production, 2019, (21), 106-115. https://doi.org/10.37101/ftpgp21.01.004 ABSTRACT Purpose. Investigation of
the processes of self-heating of a coal mine section away from the face,
based on an asymptotic analysis of a mathematical model, which takes into
account the case of tight contact of coal with rock at great depths of
formation and conditions when the heat of the chemical reaction of coal
oxidation is transmitted to the surrounding environment mechanism of thermal
conductivity only. Methods. The work is based on theoretical studies,
including methods of thermodynamics, statistical physics, and asymptotic
analysis. Findings. Analysis of the kinetics of heat
transfer in the coal bed allowed us to investigate the process of its
self-heating and to find that when the contact area of the rock is heated,
the heat flow from the coal decreases and therefore the temperature of the
coal increases so that the stationary regime disappears. In other words, the
coal temperature rises, albeit slowly but infinitely, and the stationary
state output is absent at all values of the heat transfer coefficient and the
thermal conductivity of the rock. Originality. For the first time, a theoretical
model of coal self-heating in a compact array is investigated,
when the heat of a chemical oxidation reaction of coal is transmitted to the
environment (enclosing rocks) only by the mechanism of thermal conductivity.
New in the development of this model is the fact that the host rocks are heated near the surface of their contact with coal.
The density of heat flow from coal into the rock is determined, according to
Newton's law, by the difference of contact temperatures of coal and rock, not
by the difference between the temperatures of coal and the average temperature
of the surrounding rocks, as was done previously. Practical
implications. The
results obtained allow us to estimate the degree of influence and priority of
parameters and characteristics of self-heating dynamics, as well as to
determine the duration of this process, in particular the time of reaching
the critical temperature of self-ignition of coal in the fire hazardous area
of the formation. Keywords: coal, oxygen, self-heating, spontaneous combustion, fire REFERENCES 1. Feldman, Е.P., Kalugina, Т.О., & Chesnokova, О.М. (2018) Matematychna modelʹ teploperenosu u vuhilʹnomu
plasti na velykykh hlybynakh. Fizyko-tekhnichni problemy hirnychoho vyrobnytstva, (20),
9-14. 2. Gluzberg Ye.N. (1986). Teoreticheskiye osnovy prognoza i profilaktiki shakhtnykh endogennykh pozharov. Moskva: Nedra. 3. Sian Zhang, Ting
Ren, Yuntao Liang, & Zhongwei Wang. (2016). A review on numerical solution to self-heating
of coal stockpile: mechanism, theoretical basis, and variable study. Fuel. (102), 80-109. DOI:10.3892/mmr.2015.3167 4. Veselovskiy V.S., Vinogradova
L.P., Orleanskaya G.L. (1972). Fizicheskiye
osnovy samovoz-goraniya uglya i rud. Moskva: Nauka. 5. Feldman, E.P., & Starikova,
I.G. (2013). Samonagrevaniye ugol'nogo
plasta v usloviyakh za-trudnennogo dostupa kisloroda. Khimiya tverdogo topliva, (1), 16-23. DOI: 10.7868/S0023117713010039 6. Shcherban' A.N., Kremnev O.A.
(1951). Issledovaniye koeffitsiyentov
teploprovodnosti v mo-delyakh
gornykh vyrabotok, Kiyev: Iz-vo AN USSR. ABOUT AUTHORS Feldman
Eduard, Doctor of Physical and Mathematical Sciences, Professor, State
Scientific Worker, Department of Physics of Coal and Rock, Institute for
Physics of Mining Processes of the National Academy of Sciences of Ukraine,
2A Simferopolskaya Street, Dnipro, Ukraine, 49600.
E-mail: edward.feldman.40@gmail.com Kalugina Nadiia, Doctor of
Engineering Sciences, Scientific Secretary of the Institute for Physics of
Mining Processes of the National Academy of Sciences of Ukraine, 2A Simferopolskaya Street, Dnipro, Ukraine, 49600. E-mail:
kalugina_n_a@ukr.net Chesnokova Oksana, Researcher, Department of Physics of Coal and Rock, Institute
for Physics of Mining Processes of the National Academy of Sciences of
Ukraine, 2A Simferopolskaya Street, Dnipro,
Ukraine, 49600. E-mail: chesnokova0507@gmail.com
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