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预氧化煤体的力学参数和导热特性关系研究

Study on relationship between mechanical parameters and thermalconductivity of pre-oxidized coal

  • 摘要: 为了研究不同预氧化温度对煤体基础力学参数、导热特性参数的影响,以及两参数之间的线性相关度,选取新疆硫磺沟长焰煤,使用程序升温箱对煤样进行30、80、140、200℃的预氧化处理,再借助MTS880电液伺服试验机、LFA457激光导热分析仪和FF35 CT工业断层扫描仪机来研究煤体力学参数、导热系数及内部孔裂隙的变化情况,并引入Pearson相关系数来定量计算弹性模量和导热系数间的线性相关度。结果表明:140℃预氧化作用下煤样的弹性模量、抗压强度和导热系数都最大;200℃预氧化作用下煤样的微孔裂隙相对来说最多,而弹性模量、抗压强度最小;预氧化温度在30~200℃,煤体的弹性模量和导热系数的相关系数不小于0.992,为高度正相关,都随着预氧化温度的升高呈现出先增大后减小的趋势。

     

    Abstract: In order to study a different pre-oxidization temperature affected to coal basic mechanics parameter and thermal conductivity characteristic parameters as well as the linear correlation between the two parameters, a long-flame coal from Liuhuanggou, Xinjiang was selected, a programmed temperature rising box was applied to the pre-oxidization treatment of the coal samples with the temperatures of 30, 80, 140 and 200 ℃. Then a MTS880 electro-hydraulic servo testing machine, LFA457 laser thermal conductivity analyzer and FF35 CT industrial computed tomography system were applied to study the coal mechanics parameter, thermal conductivity coefficient and crack variation condition within the internal boreholes. The correlation coefficient was introduced to quantitatively calculate the linear correlation between the elastic modulus and the thermal conductivity coefficient. The results showed that under the pre-oxidation function with a temperature of 140 ℃, the elastic modulus, compressive strength and thermal conductivity coefficient would be the largest in all. Under the pre-oxidation function with a temperature of 200 ℃, the micropore cracks of the coal samples would relatively be the maximum and the elastic modulus and compressive strength would be the minimum. When the pre-oxidization temperature was at 30~200 ℃, the correlation coefficient between the elastic modulus and thermal conductivity coefficient would be greater or equal to 0.992, would be positively correlated with the height and all would be firstly increased and then would be reduced in tendency with the pre-oxidization temperature increased.

     

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