煤岩导热特性实验及其对围岩温度场影响

Experiment on thermal conductivity of coal and its influence on temperature distribution of surrounding rock

为研究煤和岩石的导热特性对围岩温度场的影响,选取多个矿井的煤、岩样品,采用LFA457型激光导热系数测试仪测定不同温度下煤和岩石的热物理参数.根据实验得到的煤岩热物理参数,采用数值模拟的方法研究围岩热物理参数对围岩温度场的影响规律.研究结果表明:煤的热扩散系数和导热系数远小于岩石的热扩散系数和导热系数,而煤的比热容普遍高于岩石的比热容;煤和岩石的热扩散系数和导热系数均随着温度的升高而呈幂函数关系减小,而其比热容随着温度的升高呈线性增加.围岩热物理参数不同时,调热圈半径与围岩热扩散系数呈幂指数关系递增,壁面与风流温差随蓄热系数增加而线性增大.

In order to study effects of coal and rock thermal conductivity on temperature distribution of surrounding rock,thermal physical parameters in different temperatures of coal and rock samples selected from several coal mines were determined by using NETZSCH LFA 457 Micro Flash. According to the thermal physical parameters of coal and rock obtained from the experiment, the influence of the thermal physical parameters of the surrounding rock on the temperature field of the surrounding rock was studied by using numerical simulation. The results of study show that thermal diffusivity and thermal conductivity of coal is much smaller than that of rock, and the specific heat capacity of coal is higher than that of rock. The thermal diffusion coefficient and thermal conductivity of coal and rock show a power function relationship with the increase of temperature, while the specific heat capacity increases linearly with the increase of temperature. When thermal physical parameters of surrounding rock are different, the radius of cooled zone and thermal diffusivity increase exponentially, and the temperature difference between wall surface and air temperature increases linearly with the increase of heat storage coefficient.