Numerical simulation of temperature field in surrounding rock of coal mining face based on cyclic advancement algoritm

With the increasing depletion of shallow coal resources, deep mining has become the new normal for coal resources development. The high temperature and high humidity thermal environment in deep mines jeopardizes the health of operators, increases the failure rate of electromechanical equipment, and is very likely to cause safety accidents underground. As one of the most important heat sources in the coal mining face, the heat dissipation calculation of high-temperature surrounding rock has long relied on fitting empirical equations and lacks a scientific and reasonable calculation method.Based on Fourier's law and the law of energy conservation, a two-dimensional non-stationary mathematical model of surrounding rock temperature field in the coal mining face was established, and the model was discretized by the finite volume method. Then a new algorithm of cyclic advancing was proposed to simulate the actual coal cutting process by the intermittent movement of the coordinates, which significantly improves the calculation accuracy of heat dissipation of high-temperature surrounding rock in coal mining face under dynamic advancing conditions. Subsequently, the cyclic advancing algorithm process was introduced in detail with a single node as an example, and the numerical solution program was developed independently based on the Visual Studio programming platform. Finally, we carried out numerical simulation and verification of the temperature field and heat dissipation law of the high-temperature surrounding rock in the coal mining face in conjunction with the engineering background. The results show that: the simulation results are basically consistent with the trend of the field measured data, and the average relative error of the model is 6.15%. During the continuous cycle of coal cutting, the temperature field of the surrounding rock shows the characteristics of cyclic change. Within a cycle, the heat dissipation intensity of the surrounding rock in each region reaches the peak at the beginning of the coal cutting cycle, then the unstable heat transfer coefficient begins to fall rapidly, and the downward trend gradually slows down. The traditional fitting empirical formula neglects the change of the heat dissipation intensity of surrounding rock with time in the process of coal cutting cycle, and overestimates the heat dissipation capacity of surrounding rock. In the coal mining face with serious thermal damage, the heat dissipation of surrounding rock can be effectively reduced by appropriately slowing down the feed rate or adopting the cutter head of the coal miner with a shallower cut-off depth.