关键词: 煤自燃 , 储煤堆 , 重力热棒 , 布置方式 , 降温幅度 , 移热效率

Abstract: In order to grasp the heat transfer efficiency parameters of gravity heat-pipes in the local high-temperature abnormal area of large coal storage piles, this paper adopts a research method combining a scaled experimental platform and the placement of gravity heating rods in the high-temperature area of the inlet of large coal storage piles. The optimal efficiency parameters and range of gravity heat-pipe transfer in coal piles are studied, an in-situ test conducted to verify the thermal transfer efficiency by heat-pipe in a large-scale coal stockpile. The results show that the repeatability experiment proves that there are differences exist on the thermal transfer efficiency and range of heat-pipe under the different arrangements. As the insertion ratio, windward angle and the external air speed of heat-pipe is 1:4, 90° and 2.0 m/s, respectively, the temperature of the coal stockpile decreases from 150 ℃ to 36 ℃, the maximum heat transfer rate reaches 32% at an average cooling rate of 1.55 ℃/h, and the maximum heat transfer radius determined by the heat flux density method reaches 50cm, thus the thermal transfer efficiency and range are optimal. An in-situ test is carried out on a large coal stockpile in Cuijia Gou coal mine, The internal temperature of the coal stockpile in the gravity heat rod transfer area decreased significantly and exhibited stage characteristics. Compared with the high-temperature area of coal stockpile, the temperature decreased to below 40 ℃, and the heat transfer effect is significant. This study can provide theoretical basis for determining the basic parameters of gravity heat-pipe for thermal transfer technology.