采空区氧化-升温耦合模拟相似准则及传热相似性研究

氧化升温规律是衡量采空区内自燃的重要指标。使用相似材料在室温下进行采空区升温规律相似实验是制约采空区温度场实验发展的瓶颈。根据采空区氧化升温耦合数学模型,导出了保证温度场相似比为1的相似准则,研制出了一种与煤氧化机理相似度极高的自热型相似材料,并通过DSC-TG联用实验和程序升温实验,对相似材料的放热特性、耗氧特性、活化能的变化及其与煤的传热相似性进行了实验研究。研究表明:相似材料与煤的氧化机理相似,且在室温下就开始放出大量的热,放热量可以达到煤的4.5倍,耗氧速率是煤的120倍,添加自热材料使得煤的活化能降低了20~30 k J/mol。相似材料在动态采空区实验中的应用结果表明,采空区升温规律实验值与模拟值及实测值基本吻合,可以从氧化升温耦合的角度对采空区升温规律进行模拟研究。

Similarity criterion and heat transfer similarity of oxidation temperature coupled simulation in gob

Oxidation heating law is an important index to measure spontaneous combustion in gob.Using similarity material to study on temperature regulation of gob limits the development of temperature field experiment.According to the mathematical model of coupled oxidation and heating,the similarity criterion was calculated,ensure that temperature similarity criterion ratio was 1,a kind of similarity material that was highly similar to coal oxidation mechanism was developed,and the experimental study on heat transfer similarity including heat release characteristics,oxygen consumption characteristics and activation energy of similarity material was carried out through DSC-TG experiment and programmed temperature experiment.The results showed that:oxidation mechanism of similarity material and coal was similar,and it can release a large amount of heat at room temperature,the heat was 4.5 times as much coal as coal,the rate of oxygen consumption was 120 times of coal,the activation energy of coal was reduced by 20-30 kJ/mol through adding self-heating material.The results of the application of similarity material in the experiment of dynamic gob indicated that:simulated and measured values of temperature heating law in gob were in agreement,and the temperature heating law can be simulated from the perspective of coupled oxidation and heating.