摘要
采用计算流体力学(CFD)软件对煤粉颗粒在平面扩散火焰系统中的着火和燃烧过程进行了详细的数值模拟,测量了不同热协流气氛(O_(2)/N_(2)、O_(2)/CO_(2))、温度(1400~1800K)和氧气体积分数(10%~30%),特别是高温低氧(1800K,10%O_(2))环境下的气体温度场和颗粒温度分布,获得了MILD燃烧工况下煤粉颗粒着火和燃烧特性.结果表明,在高温低氧环境下,煤粉颗粒的着火距离明显缩短,气体温度场更加均匀.1800K协流温度下,随着氧气体积分数每提高10%,其着火距离缩短12%~14%,氧气体积分数为10%时的烟气温度波动系数比氧气体积分数为20%时下降9%.与O_(2)/N_(2)气氛相比,在O_(2)/CO_(2)气氛中相同热协流温度和20%氧气体积分数下,着火距离增加了2.7~3.4 mm,烟气平均温度降低了168~183 K.
The ignition and combustion processes of pulverized coal particles in a planar diffusion-flamelet-based system were numerically simulated using the Computational Fluid Dynamics(CFD)software in detail.The gas temperature fields and particle temperature distributions under different thermal coflow environments(O_(2)/N_(2) and O_(2)/CO_(2)),temperatures(1400—1800K),and oxygen volume fractions(10%—30%)were measured,with a focus on the high-temperature and low-oxygen environment(1800K and 10%O_(2)).The ignition and combustion characteristics of pulverized coal particles under moderate and intense low-oxygen dilution(MILD)combustion conditions were obtained,showing that in the high-temperature and low-oxygen environment,the ignition distance of pulverized coal particles was obviously shortened and the gas temperature field was more uniform.Specifically,the ignition distance decreased by 12%—14%with every 10%increase in the oxygen volume fraction at 1800K.In addition,the fluctuation coefficient of flue gas temperature decreased by 9%when the oxygen volume fraction was reduced from 20%to 10%.Compared with those in the O_(2)/N_(2) environment,the ignition distance increased by 2.7—3.4 mm while the average flue gas temperature decreased by 168—183 K in the O_(2)/CO_(2) environment under the same coflow temperature and 20%oxygen volume fraction.
作者
周博斐
张廷尧
周月桂
Zhou Bofei;Zhang Tingyao;Zhou Yuegui(Institute of Thermal Energy Engineering,School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《燃烧科学与技术》
CAS
CSCD
北大核心
2021年第6期653-658,共6页
Journal of Combustion Science and Technology
基金
国家重点研发计划资助项目(2016YFB0600701)
国家自然科学基金资助项目(51761125011).
关键词
低氧稀释燃烧
富氧燃烧
着火距离
温度均匀性
数值模拟
low-oxygen dilution combustion
oxy-fuel combustion
ignition distance
temperature uniformity
numerical simulation