摘要
为了研究低NOx旋流燃烧器出口流场特性以及其与水冷壁高温腐蚀的相关性,使用三维颗粒动态分析仪(PDA)测量了不同二次风风量下的低NOx旋流燃烧器出口附近的轴向、径向、切向以及湍动速度分布、回流区的形状、颗粒浓度分布以及颗粒粒径分布.结果表明:在该燃烧器出口附近有一个环形回流区,回流区的大小以及位于二次风区域的径向速度和切向速度都随着二次风风量的增大而增大;颗粒浓度呈现内浓外淡的分布,随着二次风风量的减小,这种趋势更加明显;位于中心区域的粒径略小于外围颗粒直径,二次风风量对其影响较小;颗粒的集中分布容易导致煤粉不易燃尽.气流携带煤粉可能冲刷水冷壁,造成高温腐蚀.因颗粒直径为内小外大的分布,这使得较大的颗粒容易穿过回流区到达壁面造成水冷壁沉积腐蚀.
In order to investigate the flow characteristics of a low NOxswirl burner and the correlation between the flow characteristics and high temperature corrosion on the side walls,an experimental investigation on different mass flow rates of secondary air was conducted using a three-component particledynamics anemometry（PDA）system.Velocities and turbulent velocities,the shape of the recirculation zone,particle concentrations and particle diameters were obtained.Results showed that there is an annular recirculation zone near the burner outlet,and its size and the radial and tangential velocities located in secondary air region all increase with the increase of the mass flow rate of secondary air.Particles are rich in centre and lean outside and this tendency is more obvious with the decrease of the mass flow rate of secondary air.The size of particles located in the central region is smaller than that in the outside,which is hardly influenced by the mass flow rate of the secondary air.The centre rich distribution of particle concentration is easy to cause the badly burnout of pulverized coal.The air flow carrying coal particles may impact the water wall tubes,resulting in high temperature corrosion.The distribution of the particle diameter also causes that large particles can easily penetrate the recirculation zone to collide with the side water walls,which might lead to deposit attack on the water wall tubes.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2014年第12期2162-2171,共10页
Journal of Zhejiang University：Engineering Science
基金
国家"973"重点基础研究发展规划资助项目(2009CB219802)
国家科技支撑计划资助项目(2011BAA04B01)
关键词
高温腐蚀
低NOX燃烧器
PDA
气固两相流
high temperature corrosion
low NOxburner
PDA
gas/particle two-phase flow
