In the process of advancing the working face, the temperature rise and oxidation characteristics of residual coal in goaf and the prediction of index gas are of great significance to mine fire prevention and safety production. Based on the coal spontaneous combustion test, the oxygen consumption and heat release characteristics of coal spontaneous combustion were analyzed by taking coal samples at the working face and carrying out temperature-programmed experiments in the laboratory. The characteristic temperature and index gas of coal spontaneous combustion were determined as the judgment bases of “three zones” of spontaneous combustion in goaf, and the influencing factors of coal spontaneous combustion in goaf under Y-type ventilation were analyzed. Based on the test results, the changes of gas composition in goaf during the advancing of the W1310 working face were monitored. According to the actual situation of the W1310 working face in the Gaohe energy mine of Lu’an group, the multifield three-dimensional numerical simulation calculation and analysis of gas composition in goaf were carried out, and the distribution of oxygen concentration field in goaf under different air volume ratios of machine roadway and air roadway was studied. Through the analysis of the parameters of porous media in the goaf, combined with the actual situation, the user-defined function was compiled for the key parameters such as porosity, viscous resistance coefficient, and inertial resistance coefficient of porous media in the goaf. The three-dimensional seepage field, gas concentration field, oxygen concentration field, and pressure field of the gas components in goaf during the advancement of the goaf working face were simulated. The comparison of the numerical simulation results with the field-measured results shows good agreement. In order to consider safety, the numerical simulation results with a wide oxidation temperature rise zone are used for linear regression, and the regression equation is used to dynamically determine the O 2 concentration at a point away from the goaf and to determine the “three-zone” state of the point, which is of great significance to guide the progress of the working face and safe production.

The hazards caused by gas explosion are mainly due to high temperatures and shock waves. It is of great practical significance to explore a device that can restrain these two hazards at the same time. Through the establishment of the gas explosion calculation model, a numerical analysis of the flame propagation in the three types of pipelines, including the empty pipe, the single metal foam pipe, and the high-temperature heat pipe metal foam composite structure, was carried out. The numerical results are compared with the relevant experimental results. The accuracy, rationality, and accuracy of the calculation model is verified. The research results show that that the gas explosion flame propagation develops fastest and accelerates in the empty pipe, followed by a single metal foam pipe. The gas explosion flame in the pipe with the high-temperature heat pipe metal foam composite structure develops the slowest. The composite structure composed of the high-temperature heat pipe and metal foam is an obvious choice to attenuate the temperature and overpressure of gas explosion. The high-temperature heat pipe can rapidly transmit heat in the form of phase change, and metal foam can effectively reduce the explosion pressure wave. The composite structure with the high-temperature heat pipe, and metal foam, destroys the coupling between flame and pressure wave, which acts as a barrier to explosion. It can effectively reduce the energy of flammable and explosive gas in the rear part of the pipeline and restrain the occurrence of the two explosions. The research results provide a scientific basis for the technical application of new, effective anti-explosion devices in coal mines.

Considering the characteristics of narrow underground space and energy distribution, based on blade element momentum theory, Wilson optimization model and MATLAB programming calculation results, the torsion angle and chord length of wind turbine blade under the optimized conditions were obtained. Through coordinate transformation, the data were transformed into three-dimensional form. The three-dimensional model of the blade was constructed, and the horizontal axis wind turbine blade under the underground low wind speed environment was designed. The static structural analysis and modal analysis were carried out. Structural design, optimization calculation and aerodynamic analysis were carried out for three kinds of air ducts: external convex, internal concave and linear. The results show that the velocity distribution in the throat of linear air duct is relatively uniform and the growth rate is large, so it should be preferred. When the tunnel wind speed is 4.3 m/s and the rated speed is 224 rad/s, the maximum displacement of the blade is in the blade tip area and the maximum stress is at the blade root, which is not easy to resonate. The change rate of displacement, stress and strain of blade is positively correlated with speed. The energy of blade vibration is mainly concentrated in the swing vibration of the first and second modes. With the increase in vibration mode order, the amplitude and shape of the blade gradually transition to the coupling vibration of swing, swing and torsion. The stress and strain of the blade are lower than the allowable stress and strain of glass fiber reinforced plastics (FRP), and resonance is not easy to occur in the first two steps. The blade is generally safe and meets the design requirements.