随着天然气、煤层气的不断开采和广泛应用,对甲烷-空气非预混燃烧特性的研究显得尤为重要.基于涡耗散理论,采用有限容积法建立组分燃烧与输运控制方程,针对长2 m,直径为0.9 m的圆筒形燃烧器内甲烷-空气非预混燃烧过程进行数值计算.分析了组分不同入口流速、温度对燃烧过程燃料转化率的影响.结果表明:随着空气入口流速的不断增加,甲烷空气非预混燃烧过程不充分,在距入口轴向2 m处,水和CO2的量相对较少,而氧气较多,转化率较低;随着甲烷入口流速的不断增加,非预混燃烧过程相对充分,燃料转化率提高;当改变甲烷入口温度时发现:随着甲烷温度的升高,燃烧器内氧气质量分数增加,非预混燃烧过程不充分,转化率低.提高甲烷入口流速,降低甲烷温度可有效提高燃烧过程燃料的转化率.%With the unceasing exploiting and wide application of liquefied natural gas(LNG) and coalbed methane ( CBM), it is very important for the research of the non-premixed burning process of methane and air. Based on the theory of the vortex dissipation, by using the limited volumetric method the controlling equation of the burning and transporting phase was established. The non-premixed burning process of methane and air in the cylindrical combustor with length of 2 m and diameter of 0.9 m was simulated numerically. The effects of air and methane inlet flow and temperature on the conversion in burning process were analyzed. The research results show that at the place of 2 m away from the axial inlet with the air inlet flow increasing, the methane and air mixture burns insufficiently, the mass fraction of water and CO2 is low, however, the mass fraction of oxygen is high, and the conversion is low; with the methane inlet flow velocity increasing, the methane and air mixture burns sufficiently, and the conversion is high; with the methane inlet temperature increasing, the mass fraction of oxygen is adding in the combustor, the non-premixed methane and air burn insufficiently, and the conversion is low. Enhancing the methane inlet flow velocity and lowering the methane temperature may improve the fuel conversion in the process of the burning effectively.
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