为了研究风粉流动特性对煤粉燃烧的影响，以带预燃室的逆喷旋流燃烧器为对象，利用14 MW煤粉燃烧试验台架对逆向射流和直流2类进入方式进行热态台架研究。基于高温热电偶、烟气分析仪和高速摄像机3种测量手段，获取温度、组分体积分数、火焰形态尺寸数据，结合煤粉燃烧基础理论分析不同区域的燃烧过程，揭示了不同风粉流动特性下煤粉燃烧的差异。研究结果表明：风粉逆向射流和直流进入时，煤粉在预燃室内实现稳燃低氮，且避免高温腐蚀结渣现象，其差异为预燃室内煤粉燃烧份额及预燃室外火焰行程。在预燃室内，逆向射流的煤粉停留时间长，与旋流内二次风混合充分，温度最高为1 255 ℃，O2径向衰减过程中平均下降速率为0.139%/mm，形成环状还原性气氛区域，CO体积分数超过50 000×10^-6，煤粉燃烧份额较高同时抑制NO_x生成；直流的煤粉停留时间短，与旋流内二次风混合弱，温度最高为1 096 ℃，O₂平均下降速率在上游为0.135%/mm，下游为0.080%/mm，形成中心还原性气氛区域，CO体积分数同样超过50 000×10^-6，抑制NOx生成的同时煤粉燃烧份额较低。在预燃室外，逆向射流煤粉随旋流内二次风前行，火焰明亮粗短发散，长度为2 697 mm、出口直径和发散角度为760 mm和24.11°，行程较短；直流煤粉随高速射流前行，火焰细长亮度略低，长度为5 747 mm、出口直径和发散角度为536 mm和7.81°，行程大幅增加。

In order to study the effect of mixed air and particle flow characteristic on pulverized coal combustion,a reverse-jet swirl burner with cone pre-combustion chamber is selected as investigation objection,the 14 MW pulverized coal combustion experimental system is used to research combustion characteristic with reverse-jet and jet flow.On the basic of high temperature thermocouple,flue gas analyzer and high speed camera measurement methods,the dates of temperature,species volume concentration and flame shape scale are obtained.Then,combining with pulverized coal combustion basic theory,the combustion process of different regions are discussed to reveal the difference of reverse-jet and jet flow on pulverized coal combustion characteristic.The experimental results show that the stable and low nitrogen combustion can be achieved in pre-combustion chamber both reverse-jet and jet flow,and high temperature corrosion and slagging are avoided.But the difference of them are combustion fraction in pre-combustion chamber and flame scale beyond pre-combustion chamber outlet.In pre-combustion chamber,the maximum temperature is 1 255 ℃ and O₂ decaying rate is 0.139%/mm for reverse jet case,ring reduction atmosphere zone is formed and CO volume concentration more than 50 000×10^-6,indicating that the combustion fraction is larger.The maximum temperature is 1 096 ℃ and O₂ decaying rates are 0.135%/mm and 0.080%/mm in upstream and downstream respectively for jet case,central reduction atmosphere zone is formed and CO volume concentration more than 50 000×10^-6,indicating that the combustion fraction is smaller.Beyond pre-combustion chamber outlet,the flame shape is bright and tubby for reverse-jet case,and flame length is 2 697 mm,diameter and divergence angle is 760 mm and 24.11°,indicating that the combustion process is shorter.The flame shape is slender and slightly low brightness for jet case,and flame length is 5 747 mm,diameter and divergence angle is 536 mm and 7.81°,indicating that the combustion process is longer.

1 煤粉燃烧试验

   1.1 试验系统

   1.2 试验煤种及工况

2 结果与讨论

   2.1 预燃室内温度分布

   2.2 预燃室内组分体积分数分布

   2.3 预燃室外火焰形态

3 结论