【摘要】 采用计算流体力学软件PHOENICS,选择合理的数学模型,对1台1GW超超临界单炉膛双切圆炉内的煤粉燃烧过程进行数值模拟,得出了炉内主燃区各截面上的速度场以及温度分布规律。结果表明,燃烧器布置在前后墙导致主燃区下﹑中层区域炉内气流为斜椭圆形,上部区域为长轴基本平行于两侧墙的椭圆形;温度在斜椭圆长轴所指的水冷壁附近局部区域较高,形成“热角”区域,在其它主燃区的水冷壁附近温度较低,且在温度较高的水冷壁附近均存在气流刷壁现象,热态运行时易形成高温腐蚀和结渣条件;针对这一问题,改变主燃区配风方式,因此,综合考虑结渣、焦炭燃尽效果以及NO排放量这几个因素,正宝塔配风方式下的工况较优。更多还原

【Abstract】 The Computational Fluid Dynamics(CFD)code PHOENICS was employed to evaluate pulverized coal combustion process in a 1GW dual circle tangential firing single chamber boiler.The distribution of gas velocity and temperature field in the down,middle and upper combustion zone of the furnace was obtained.The numerical results showed that the arrangement style of burners on walls leads to ellipse shape flow pattern,the long axis of which was slant against the sides wall in the down and middle part of the combustion field,but parallel to the two side walls in the upper.Temperature in the combustion field,pointed by the long axis of the slant ellipse shape flow,was much higher than that in other position.’Hot corners’ are formed by the aerodynamic character in furnace.Moreover,the impingement of the gas flow on water-cooled walls existed in the higher temperature field,which may lead to high temperature corrosion and slag at such zone during operation.In order to solve this problem,the secondary air distribution in the main combustion zone was altered.The results showed that the ’pagoda’secondary air distribution was optimum,taking account of slag resistance,char combustion efficiency and overall NO emission level.更多还原