含内热源松散煤体热湿迁移特性研究

Study on heat and moisture migration characteristics of loose coal with internal heat source

为研究松散煤体内部热湿迁移规律,建立松散煤体多场-相变-扩散耦合数学模型,对热力驱动下的温、湿度场时空演变规律进行仿真研究;通过热湿迁移特性实验平台,对数值模拟结果的有效性与准确性进行验证。研究结果表明:温度相对误差小于5%,含湿量相对误差小于8%;松散煤体温度逐渐升高,温升速率逐渐减小,温度最终趋于稳定值,沿轴线方向温度呈指数性降低;松散煤体湿度场可分为煤体含水率和空气含湿量,在空间上可分为含水率减少区、含水率增大区和含水率不变区,随着计算进行,峰值含水率逐渐增大且向远离热源方向移动;含湿量相较于实验初期均有所增大,沿轴线方向先呈线性降低,后呈指数性降低且线性区域越来越大,指数性区域越来越小。

In order to study the law of heat and moisture migration inside loose coal,a multi-field,phase transition and diffusion coupled mathematical model of loose coal was established,and the simulation research was carried out on the temporal and spatial evolution law of temperature and humidity fields under thermal driving.The validity and accuracy of the numerical simulation results were verified by the experimental platform of heat and moisture migration characteristics.The results showed that the relative error of temperature was less than 5%and the relative error of moisture content was less than 8%.The temperature of loose coal increased gradually and finally remained unchanged,the temperature rise rate decreased gradually,and the temperature decreased exponentially along the axial direction.The moisture field of loose coal could be divided into coal moisture content and air moisture content,and the moisture content could be divided into reducing area,increasing area and constant area in space.With the progressing of calculation,the peak moisture content gradually increased and moved away from the heat source.The moisture content increased comparing to the initial stage of the experiment,which first decreased linearly along the axis direction,then decreased exponentially,and the linear region was growing,while the exponential region was getting smaller.