摘要
文章通过引入体平均参量,导出模拟煤堆自燃过程的二维非稳定数学模型。该模型考虑了依赖于温度和氧气浓度的局部氧化反应,以及依赖于煤堆表面温度和水蒸气分压力的表面蒸发过程。氧气和水蒸气通过对流和扩散传递于煤堆孔隙之中,热量通过导热和对流传递。为了求解该控制方程,实验测出20～65℃温度范围内的氧化速率,并推广到更高的温度范围。实地堆放一个可视作二维形状的煤堆,采用数值的方法对控制方程进行求解。结果表明:煤堆孔隙率、水分、氧气浓度以及初始温度对煤自燃发热过程有着重要的影响。
A two-dimentional mathematical model of the spontaneous combustion of large coal stockpiles has been developed,by means of a new method——averaging volume method。The unsteady-state model takes into account a local oxidation reaction which depends on temperature and the concentration of unreacted and reacted oxygen,as well as a surface evaporation which depends on temperature and the partial pressure of vapor in surface of pile and vapor in atmosphere。The transport processes of diffusing and convection take mobile reaction,oxygen,from the boundary to the distributed reaction where heat energy is released,and then convey the later back to the boundary。To solve the eqvations,rate of heat generation of fine coal is measured at various temperatures in the range 293-338K。The equations are solved numerically and results give valuable insight into the nature of self-heating。The influence of coal partical size,voidage,moisture,concentration of oxygen and ambient temperature are discussed with the conclusion that voidage,moisture,oxygen and ambient temperature play a crucial role in determing the safety or otherwise of a coal stockpile.
出处
《工业锅炉》
2004年第4期26-29,37,共5页
Industrial Boilers
关键词
自燃
煤堆
计算
Spontaneous combustion
Coal stockpiles
Calculation
