多孔壁风耦合空气分级条件下煤粉燃烧的数值模拟  

Numerical Simulation of Pulverized Coal Combustion in Staged Air Coupling with Multi-Hole Wall Air

作　　者：马红和[1] 李军[1] 周璐[1] 赵军 MA Honghe;LI Jun;ZHOU Lu;ZHAO Jun(Department of Thermal Engineering,Taiyuan University of Technology,Taiyuan 030024,China;School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]太原理工大学热能工程系,太原310024 [2]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2020年第10期137-143,共7页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(51706151);山西省高校科技创新计划资助项目(2019L0147)。

摘　　要：为阐明多孔壁风耦合空气分级对煤粉燃烧的作用特性,利用商业软件Ansys Fluent进行了数值模拟研究,并采用用户自定义函数法(UDF)编译写入了焦炭气化反应和NO被焦炭异相还原的宏文件。探究了燃烧炉中流场、温度场和主要组分浓度场的分布规律,分析了多孔壁风对NOx排放和燃烧效率的影响。结果表明:多孔壁风系数存在优化值,此时不会明显影响炉内的燃烧组织;多孔壁风可在主燃区和还原区壁面形成空气膜,其中,主燃区空气膜中氧气体积分数大于4%,还原区不低于2%,阻止了还原性气体的腐蚀;多孔壁带入还原区的氧气能够与焦炭结合,在焦炭表面生成含氧络合物C(O),既能强化NO的异相还原,又能促进焦炭在燃尽区燃烧。Numerical simulation using Ansys Fluent software is performed to clarify the combustion characteristics of pulverized coal in staged air coupling with multi-hole wall air,and a user defined function method(UDF)is used to compile and write macro documents of char gasification reaction and NO dissimilar reduction by char.The distributions of flow field,temperature field and concentration field of major species are investigated,and the influence of multi-hole wall air on NO x emission and combustion efficiency is analyzed.Calculating results show that:there exits an optimal multi-hole wall air ratio,and in this case the combustion is not affected adversely;an air film is formed near the wall,and the oxygen concentrations in the primary and reduction zones are above 4%and 2%,respectively,thus the corrosion due to the reducing species is prevented;the complex C(O)is produced on the char surface in the reduction zone,which enhances the reduction of NO and promotes the char combustion after the ejection of the over-fired air.

关 键 词：煤粉燃烧 空气分级 多孔壁风 数值模拟 

分 类 号：TK223.2[动力工程及工程热物理—动力机械及工程]