Research on the Air Leakage Law of goaf under Y～shaped Ventilation Conditions Based on the "O" Ring Theory

This study takes the goaf of the 1302 working face in Shaqu Mine as the research object. Based on the "O" ring theory system, a mathematical model of gas migration in the goaf is constructed using the FLUENT numerical simulation platform, and the "three zones" division is carried out on site in combination with the bundle tube monitoring system. After comparing the on～site monitoring data with numerical simulation results, the reliability of the model was verified, and nitrogen injection fire prevention and extinguishing parameter optimization experiments were carried out. Experimental data shows good consistency between numerical simulation and on～site monitoring. The simulated widths of the oxidation zone on the inlet and return sides of the goaf are 58 m and 54 m, respectively, corresponding to on～site measured values of 60 m and 52 m, with relative errors of less than 5%; After implementing the nitrogen injection process, the width of the oxidation zone on both sides was reduced by 82.8% and 53.7%, respectively. The coupled model of air leakage and spontaneous combustion established in this study provides a theoretical basis for the engineering application of nitrogen injection fire prevention technology in coal mines.