Numerical Simulation of Coal Spontaneous Combustion around a Borehole Induced by Negative Pressure Gas Drainage

Table 1

Model parameters.

Parameters	Magnitude and unit	Parameters	Magnitude and unit
Coal density	1250 (kg/m^3)	Initial oxygen volume fraction	9.375 (mol/m^3)
Original coal permeability	0.039 (m^2)	Heat transfer coefficient	180 (W/(m^2·K))
Methane heat capacity	1625 (J/(kg·K))	Gas viscosity	(Pa·s)
Coal heat capacity	1260 (J/(kg·K))	Air viscosity	(Pa·s)
Molar air mass	0.029 (kg/mol)	Oxygen consumption constant	0.036 (mol/(m^3·h))
Oxygen diffusion coefficient	(m^2/s)	Thermal conductivity of coal	0.26 (J/(m·s·K))
Oxidation heat of coal	19744.37 (J/g)