Numerical Simulation of the Effect of Heat Transfer and Cooling of a Coal Pillar Oxidation Heat Source by a Bending Heat Pipe

During narrow coal pillar mining, a high-temperature point can easily form inside the coal pillar, leading to CSC. This study aims to investigate the effect of key layout parameters of a bending heat pipe on the heat transfer from a coal pillar oxidation heat source. The bending heat pipe (Tianjin Xinhua Energy Equipment Technology Co., Ltd., Tianjin, China) heat transfer model was constructed using the Fluent software 2021 R1; meanwhile, the effects of heat transfer of non-uniform and uniform temperature fields under different spacings (30 cm, 40 cm, 50 cm) of a single heat pipe and multiple heat pipes were studied. According to our findings, the maximum temperature error between the simulated and experimental temperature fields in the bent heat pipe under identical operating conditions is 3.8 °C, which verifies the model’s feasibility. The temperature field in each section of the coal pillar exhibits a “wave-like” change trend in the heat pipe, with the heat transfer effect diminishing markedly as the spacing increases. Considering the thermal effect and on-site operation feasibility, the optimal spacing of the two bending heat pipes is determined to be 30–40 cm. These research results can offer a theoretical foundation for the application of bending heat pipes in the advanced prevention of the hidden danger of CSC in narrow coal pillar mining.