Study on the effect of gravity heat pipe arrangement onhigh temperature point of coal pile

The existing researches have concluded that the number of gravity heat pipes, insertion depth and angle, filling rate, working fluid will affect the distribution of the internal temperature field of coal pile. However, there are few researches on the optimal arrangement of gravity heat pipes in coal pile. In order to solve the above problems, based on the gravity heat pipe heat transfer theoretical model, the heat source is equivalent to a sphere, and the effect of gravity heat pipe arrangement on the high temperature point of coal pile is analyzed by a combination of numerical simulation and experiment, and the optimal arrangement of gravity heat pipe is derived. The numerical simulation results based on Comsol software show that the depth of gravity heat pipe insertion has greater effect on the temperature of the high-temperature heat source point inside coal pile than the inclination angle of gravity heat pipe insertion. Under the same angle, the greater the gravity heat pipe arrangement depth is, the better. This means that the closer to the heat source, the better. Under the same depth, when the gravity heat pipe arrangement angle is 60, 90, 45 and 30°, the cooling range decreases in order. When the insertion depth of gravity heat pipe is 60 cm and the insertion angle is 60°, the highest cooling range reaches 61.2 ℃, and the coal pile has the best cooling effect. The experimental results based on the coal storage pile heat transfer test bench show that the optimal arrangement of gravity heat pipes is consistent with the simulation results, and the overall trend of the cooling rate is similar to the simulation results. With the increase of the inclination angle, the cooling rate of heat pipe decreases first and then increases, and the cooling rate reaches the maximum when the inclination angle of heat pipe insertion reaches 60°.