700 ℃切圆锅炉存在较严重的烟温偏差问题，利用Fluent软件，对1台660 MW的700 ℃四角切圆锅炉进行数值模拟。采用数值模拟正交试验法，对燃尽风的反切角度（因素A）、燃尽风的速度偏置（因素B）、燃尽风反切角度与燃尽风速度偏置两者可能存在的交互作用（因素A×B）、燃烧器的上摆角度（因素C）以及二次风的偏转角度（因素D）5个因素，每个因素分别设置2个水平，以炉膛出口烟温偏差为试验指标进行优化。对模拟所得数据采用极差、方差、权矩阵等3种分析方法。结果表明，各因素对试验指标重要程度的排序为：D＞A＞B＞A×B＞C，因素D的影响非常显著，因素A影响显著，其余3个因素影响不明显；各因素权重占比为：因素A（0.184）、因素B（0.068）、因素A×B（0.033）、因素C（0.024）、因素D（0.544）；数值模拟得出最佳因素与水平组合为A2B2C2D1，该组合下锅炉炉膛出口截面左、右两侧烟温偏差为6.6 K，锅炉炉膛出口截面左、右两侧烟温偏差可控制。

700 ℃ tangential firing boiler has serious flue gas temperature deviation problem. A 660 MW tangential firing boiler with 700 ℃ corners was numerically simulated by commercial Fluent software. Using the method of simulated orthogonal test,five factors,such as the anti-tangential angle of the over-fire air (factor A),the velocity offset of the over-fire air (factor B),the possible interaction between the anti-tangential angle of the over-fire air and the velocity offset of the over-fire air (factor A×B),the upward swing angle of the burner (factor C) and the deflection angle of the secondary air (factor D),were set at two levels for each factor,and the flue gas temperature deviation at furnace outlet was used as the test index for optimization. Three analytical methods,such as range,variance and weight matrix,were used to analyze the simulated data. The results show that the order of importance of each factor to the test index is:factor D > factor A > factor B > factor A×B> factor C,among which,the influence of factor D is very significant,that of factor A is significant,and that of the other three factors is not significant. The weight ratio of each factor is:factor A（0.184）,factor B（0.068）,factor A×B (0.033),factor C（0.024）and factor D（0.544）;the numerical simulation shows that the best combination of factors and levels is A2B2C2D1. Under this combination,the flue gas temperature deviation on the left and right sides of the outlet section of the boiler furnace is 6.6 K,and the flue gas temperature deviation on the left and right sides of the outlet section of the boiler furnace can be controlled.

0 引言

1 研究对象

2 模拟计算方法

   2.1 模型网格的划分

   2.2 数学模型

   2.3 边界条件

   2.4 工况设置

3 结果与讨论

   3.1 模拟验证

   3.2 炉内速度场分析

   3.3 炉内温度场分析

   3.4 P6截面速度及温度分布

   3.5 烟温偏差数值分析

   3.6 极差及方差分析

   3.7 权矩阵分析

4 结论