Research Article
Disastrous Mechanism and Concentration Distribution of Gas Migration in Fully Mechanized Caving Stope in Wuyang Coal Mine
Table 1
Numerical simulation parameters.
| | Mark | Value | Meaning |
| | rho_CH4 | 0.717 (kg/m3) | Gas density under standard condition | | rho_air | 1.29 (kg/m3) | Air density | | D | 1-5 (m2/s) | Gas diffusion coefficient | | Mug | 1.8e-5 (Pas) | Gas dynamic viscosity | | pn | -2 (KPa) | Pressure at return air exit | | Gp_c | 260 (m3/min) | Extraction quantity of high pumping roadway | | k0 | 1.45 | Natural expansion coefficient | | k1 | 1.15 | Residual expansion coefficient | | u0 | 5.1 (m/s) | Flow velocity of intake airflow roadway | | u_15 | 5-7 (m/s) | Gas emission rate of residual coal in goaf | | u_14 | 8-7 (m/s) | Gas emission rate of adjacent coal seam | | v_mol | 22.4 (l/mol) | Molar volume of gas | | M_O2 | 32 (g/mol) | Molar mass of oxygen | | M_N2 | 28 (g/mol) | Molar mass of nitrogen | | M_CH4 | 16 (g/mol) | Molar mass of methane |
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