Measurement Analysis And Numerical Simulation Of Spontaneous Combustion "Three Zone" In Gob

Spontaneous combustion of residual coal in gob is one of the major disasters in mine, formulating reasonable prevention measures is particularly important to prevent coal spontaneous combustion, but the premise of prevention is to determine the range of gob spontaneous combustion "three zone". This thesis studies the oxidation rule of residual coal spontaneous combustion in gob of2341(3) fully mechanized working face and determines the range of gob spontaneous combustion "three zone", based on the study of mechanism of coal spontaneous combustion,"three zone" division theory and numerical simulation, and taking the theory of coal spontaneous combustion as guidance, combining with laboratory experiments, field test and numerical simulation.Low temperature oxidation experiment is conducted for particle size greater than60mesh,60～80mesh and80～100mesh coal sample. The characteristics of gas products and its change law are analyzed, and the effect of particle size on the oxygen consumption rate is studied. It is obtained that the oxygen consumption rate increases with the particle size decreases, but the increase rate becomes smaller gradually.Testing system is embedded in inlet and return airway of fully mechanized working face, and the temperature and oxygen concentration distribution situation of gob is studied and analyzed during the period of mining and near the end of mining. According to the measured data, combining with the oxygen concentration division index, the range of gob spontaneous combustion "three zone" is obtained.Oxygen concentration field of gob is simulated with and without the condition of nitrogen injection by FLUENT software, and the rationality of model is confirmed through the comparison of test and simulation data under the condition of nitrogen injection. And Four observation line of Y=25m, Y=50m, Y=100m, Y=150m is defined in gob, and the oxygen concentration field is studied in different permeability. It is obtained that the diffrence of "three zones" of inlet side is lager, and return side is small in different permeability.