Numerical study on temperature field in the gob under different cooling control measures

The temperature and flow fields of the gob area are quantified in this paper. Firstly, a mathematical model for multi-physical coupling in the gob was established. The on-site test of Daqiang Coal Mine was conducted without injecting nitrogen, which verified the effectiveness of the model. The cooling effect of the nitrogen injection decreases as the distance between the air inlet side and the working surface increases. In addition, the hot air extraction was clearly evaluated and the movement of hot air was analyzed. Both nitrogen injection and hot air extraction in the mining area have a significant effect on reducing the airflow temperature at the coal mining face. The air flow temperature with nitrogen injection at each location was lower than that without nitrogen injection along the direction of the coal face. In contrast, the air temperature on the return air corner is greatly reduced after the hot air extraction measures are taken and it can improve the air thermal state near the return air corner. We can provide effective solutions to the problems of spontaneous combustion and thermal damage in high-temperature mines through theoretical research and practical exploration.

Automated summary

The temperature and flow fields of the gob area are quantified in this paper. A mathematical model for multi-physical coupling in the gob was established and its effectiveness was verified through on-site tests. The study found that both nitrogen injection and hot air extraction have a significant effect on reducing the airflow temperature at the coal mining face.