| Compared to single coal seam gobs,Composite Gobs,formed of mining of closeddistance coal seam group,have much more complicated flow field.so,it’s meaningfulto study its ventilation and gas drainage for the protection of mining of closeddistance coal seam group.As to determine the model of gob porosity, porosity continuous distributionmodel with unknown parameters was derived according to the theory of groundpressure.The permeability distribution and Inertial Resistance Coefficient modelbased on porosity model was established according to the Ergun function. Then thephysical model of Panjiang Group Jinjia coal mine ’s111811mine face was finished,as well as the objective function about measured methane concentration, which isused to evaluate reverse-solving. After finishing all these preparatory work，reverse-solving was used to study the parameters included in the continuous modelsby FLUENT numerical simulation, gob non-linear seepage model was finallydetermined.Upon the research, factors of ventilation and gas drainage of111811and11223composite gob was further studied,5factors were selected,a5factor and5levelorthogonal test was established. a combination method of orthogonal test, numericalsimulation and fuzzy comprehensive assessment was used to optimize the factors.Based on correlation theory, Uses the software of FLUENT to carry on the numericalsimulation to each experiment.Use the method of fuzzy optimization theory tomultiple-target assess the orthogonal test plans,put the fuzzy assessment relult intoorthogonal test result table and select the optimized parameters combination.To verify the optimization result of ventilation and gas drainage,flow field databefore and after the optimization was compared,the result showed that,the gasconcentration of the upper corner and the return airway reduced by21.88%and20%,while,gas drainage of Stationary Tube increased by24.78%,the optimizationresult played a good role to the protection of mining safety and gas extractioneconomies. |
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