Multi-field coupling numerical simulation heat accumulation zones in gob areas of the crossheading effect on oxidization and heat accumulation zones in gob areas

Under the ventilation condition of U + L, a crossheading has important impact on spontaneous combustion of residual coal in a gob area. In order to ensure mine safety and obtain parameters to prevent spontaneous combustion of residual coal, on the basis of the mechanism of coal oxidation and using UDF to incorporate the reaction mechanism into FLUENT, multi-field coupling numerical simulation was performed to study the distribution law of the oxidization and heat accumulation zone in a gob with a cross-heading. The results show that the air flow field, oxygen concentration field and temperature field all change when the crossheading exists, the oxidization and heat aeeumulation zone not only offsets to the return-side but also becomes deeper and wider. The distance between the erossheading and working surface affects the width of the oxidization and heat accumulation zone, and when it is 20 m, the maximum width is approximately 25 m. After 10 d of reaetion, the heating rate at the high temperature point can reach 1.24K·d^-1 in the U + L ventilation system, which is 1.5 times that in the U ventilation system. However, the position of the crossheading has little effect on the high temperature point. The temperature nearby the crossheading is the highest in the return-side temperature field of the U + L ventilation system, and the average temperature is d K higher than the same location temperature in the U system per day. With increasing distance from the crossheading to working face, the heating rate in the crossheading rim increases from 0.1 K·d^-1 to 0.9 K·d^-1. Although the crossheading does not belong to the high temperature region in the whole temperature field, it has good warming potential.