煤矿乏风瓦斯热逆流氧化的一维数值模拟

One-Dimensional Numerical Simulation of Thermal ReverseFlow Oxidation of Ventilation Air Methane in Coal Mine

为了研究煤矿乏风低含量瓦斯热逆流氧化,建立了煤矿乏风瓦斯热逆流氧化的一维数学模型,应用FLUENT软件研究了氧化床内热结构特性以及工况参数对氧化床热结构、甲烷氧化率及出口温度的影响。计算结果表明:1)氧化床内温度场基本成梯形分布,高温区沿氧化床高度方向周期性往复移动。2)随着乏风中甲烷体积分数的提高,氧化床高温区域拓宽,最高温度和出口温度也有相应的提高,甲烷的氧化率略有升高。3)随着氧化床处理乏风量的增加,氧化床内温度峰值、反应率及出口温度都有明显升高,反应区向两端移动,高温区域加宽,但甲烷氧化率随之下降。4)随着换向半周期的延长,氧化床反应区和高温区向氧化床中部移动,高温区域变窄,出口温度升高,甲烷氧化率略有下降。5)随璧面热损失的不断增加,氧化床峰值温度、高温区温度及甲烷的氧化率均降低,反应速率也下降剧烈,高温区域宽度也明显变窄。

In this paper,an one-dimensional mathematical mode was set up,to investigate the thermal reverse-flow oxidation of ventilation air methane（VAM） in coal mine,and Fluent software was adopted to simulate the effects of the thermal structures of oxidation bed and the operating condition parameters on the thermal structure,oxidation ratio of methane and outlet temperature.The results indicate that： 1） The temperature field of oxidation bed presents trapezium distribution,and the high-temperature zone makes reciprocating movement periodically along the height direction of oxidation bed.2） With the in-crease of methane concentration,the high-temperature zone widens,and the maximum temperature and the outlet temperature increase accordingly,while the oxidation ratio of methane increases slightly.3） As the ventilation air volume increases,the peak temperature,reaction rate and outlet temperature all rise significantly,the reaction zone moves towards both ends of the oxidation bed,and the high-temperature zone widens,while the oxidation ratio of methane decreases.4） With the extension of half cycle,the reaction zone and high-temperature zone move towards the center of oxidation bed,the high-temperature zone narrows down,the outlet temperature increases,and the oxidation ratio of meth-ane decreases slightly.5） With the continuous increase of heat loss on wall,the peak temperature,the temperature in high-temperature zone,and the oxidation ratio of methane gas all decrease,the reaction rate also falls sharply,while the high-temperature zone narrows down distinctly.