贫燃预混旋流燃烧器回熄火边界数值模拟  

Simulation of flash back and blow-off limits in lean premixed swirl combustor

作　　者：郭乔轩 雷福林[1,2,3] 田文栋 张哲颠[1,2,3] 肖云汉 GUO Qiaoxuan;LEI Fulin;TIAN Wendong;ZHANG Zhedian;XIAO Yunhan(Key Laboratory of Advanced Energy and Power,Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Research Center for Clean Energy and Power,Chinese Academy of Sciences,Lianyungang 222069,China)

机构地区：[1]中国科学院先进能源动力重点实验室(工程热物理研究所),北京100190 [2]中国科学院大学,北京100049 [3]江苏中国科学院能源动力研究中心,江苏连云港222069

出　　处：《热力发电》2020年第11期82-88,共7页Thermal Power Generation

基　　金：国家科技重大专项(2017-I-0009-0010)。

摘　　要：为了预测回熄火边界,采用部分预混燃烧模型对天然气旋流预混燃烧器开展计算流体力学模拟。燃烧室直径60 mm、长160 mm,模拟工况包括空气和体积分数为25%的O2+体积分数为75%的N22种氧化剂,旋流器出口轴向速度为0.6~1.5 m/s范围的回火边界,以及1.5~4.5 m/s范围内的吹熄边界。通过回火和吹熄实验数据对模型进行验证,并分析结构参数对回熄火边界的影响。对比了Realizable k-ε模型和雷诺应力湍流模型,结果表明雷诺应力模型对回熄火边界的模拟结果更好。分析了回火和吹熄前后旋流器出口截面Da的变化情况,结果表明不同气流速度条件下回火临界点的1/Da以及吹熄临界点的Da和混合分数具有一定的关系。保持几何旋流数不变,对比分析了3种旋流器进口结构回熄火发生前后的流场变化及回熄火边界的变化,结果表明结构参数对回火和吹熄区间的影响作用相反,存在最优的进口长度和宽度组合使得由回火到吹熄的稳定燃烧区间最大。To predict the boundaries of flashback and blow-off,partial premixed combustion model is employed to perform computational fluid dynamics(CFD)simulation of the natural gas premixed swirl burner.The combustion chamber is 60 mm in diameter and 160 mm in length.The simulation conditions include two oxidizers,the air and the 25%O2+75%N2(volume fraction).The swirler exit is flash back with axial velocity of 0.6~1.5 m/s and blowoff of 1.5~4.5 m/s.The model is verified by the flashback and blow-off experimental data,and the influence of the structural parameters on the boundaries of flash back and blow-off is analyzed.The Realizable k-εmodel and Reynolds stress turbulence model are compared,and it shows the Reynolds stress model has better simulation results.The changes of Da number at the section of swirler exit before and after flashback and blow-off are analyzed.It is found that there is a certain relationship between 1/Da at critical flashback point and mixing fraction,as well as Da at critical blow-off point and mixing fraction at different gas velocities.Keeping the geometric swirl number unchanged,the flow fields before and after the flashback and blow-off and their boundaries for three kinds of swirler inlet structures are compared and analyzed.The results show that,the influence of the structural parameters on flashback intervals is opposite to that on blow-off,and there is an optimal combination of the inlet length and width to maximize the stable combustion region between flashback and blow-off.

关 键 词：贫燃预混燃烧 旋流燃烧器 回火边界 吹熄边界 几何旋流数 数值模拟 

分 类 号：TK16[动力工程及工程热物理—热能工程] TK473