变风速下四角切圆锅炉燃烧特性的数值模拟  

Numerical Simulation on Combustion Characteristics of Tangentially-fired Boilers at Different Air Speeds

作　　者：李德波[1] 徐齐胜[1] 沈跃良[1] 张睿[2] 温智勇[1] 刘亚明[1] 

机构地区：[1]广东电网公司电力科学研究院,广州510080 [2]浙江大学热能工程研究所能源清洁利用国家重点实验室,杭州310027

出　　处：《动力工程学报》2013年第2期106-106,共1页Journal of Chinese Society of Power Engineering

摘　　要：采用大涡数值模拟(LES)方法对某电厂一台220t/h四角切圆锅炉在3组不同风速条件下的炉内流场、温度场、CO2、CO、O2和NO的排放特性进行了研究,并将数值模拟结果与现场的试验数据进行了对比.结果表明:在第一组模拟条件下,炉内出现不完全燃烧现象,炉膛出口处CO质量分数最大而O2质量分数最小,其他2组模拟结果表现出较好的一致性,说明在空气充足的情况下,风速不会对CO2、CO和O2的质量分数产生太大影响;当过量空气系数较小或较大时,炉膛出口处NO的质量浓度减小;模拟结果中炉膛内最高温度超过1 550℃,炉膛出口平均温度约为959℃,与试验数据较吻合,验证了模拟结果的准确性;随着风速和过量空气系数的增大,炉膛内和炉膛出口处平均温度均下降;随着风速的增大,炉内切圆半径和切圆中心位置均未发生改变,但切圆最大风速增大.The in-furnace flow field, temperature field, and the emission characteristics of CO2, CO, O2 and NO of a 220 t/h tangentially-fired boiler were studied under three different simulation conditions of air speed by Large Eddy Simulation （LES） method, of which the results were compared with actual experimental data. Results show that under the first simulation conditions, incomplete combustion may occur in the furnace, in which case, the outlet mass fraction of CO is the highest, while that of O2 is the lowest; whereas under other two simulation conditions, the results show relatively good consistency, indicating that with adequate air, the air speed will not influence much on the mass fraction of O2, CO and O2 ; when the excess air coefficient is relatively small or large, the outlet mass concentration of NO decreases; according to the simulation results, the maximum temperature in the furnace is 1 550 ℃ and the mean outlet temperature is 959 ℃, which are consistent with the experimental data, proving the simulation results to be accurate. With the increase of air speed and excess air coefficient, the mean in-furnace temperature and outlet temperature decrease. With the rise of air speed, both the tangential radius and the circle center do not change, but the maximum tangential air speed increases.

关 键 词：四角切圆锅炉 大涡数值模拟 最大风速 燃烧特性 过量空气系数 炉膛出口 质量分数 炉内流场 

分 类 号：TK222[动力工程及工程热物理—动力机械及工程]