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回转窑窑壁非稳态传热模型及窑皮厚度优化 总被引:1,自引:0,他引:1
烟气、料床、窑壁是回转窑传热过程的三要素,在确定这三要素之间传热量的基础上,建立了回转窑窑壁非稳态传热数学模型。对中铝河南分公司2号窑窑壁的非稳态传热过程进行了数值计算。结果表明:窑体旋转一周,烧成带窑壁内表面温度将在1 232~1 334℃变化,这易导致窑壁热疲劳破坏;窑皮越厚,窑壁的径向温度梯度越小,热应力越低;将烧成带窑皮厚度控制在252 mm,可使烧成带窑壁外表面温度维持在200℃。 相似文献
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CFD prediction of physical field for multi-air channel pulverized coal burner in rotary kiln 总被引:3,自引:0,他引:3
A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5 m in diameter, 90 m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss. 相似文献
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回转窑内烟气温度分布的数值研究 总被引:1,自引:0,他引:1
回转窑各操作参数如窑头过剩空气量、内外风量比、煤种和煤粉粒度等及燃烧器性能好坏对窑内火焰形状、温度分布和燃烧器性能的发挥有很大影响.据此,以一旋流式四风道煤粉燃烧器及相应的φ4.5×90 m回转窑为对象,应用流体力学计算软件CFX,研究了煤种为低挥发分无烟煤时,影响窑内火焰性能、温度分布和燃烧效率的主要因素,提出了针对该种新型燃烧器的优化的操作参数和结构参数. 相似文献