摘要
化学反应动力学模型的准确性与计算量的矛盾是限制选择性非催化还原(selective non-catalytic reduction,SNCR)数值模拟的主要因素。通过敏感性分析和引入准稳态假设,对包含60个组分、371个基元反应的SNCR详细机制—— A机制进行简化,得到包含28个组分、97个基元反应的骨架机制及最终的包含12种主要组分、8步总包反应的简化机制模型,减小了化学反应速率的计算量。进一步利用柱塞流反应器(plug flow reactor,PFR)模型计算,验证了反应温度、停留时间以及氨氮摩尔比等因素影响下简化模型的准确性,与常用的SNCR两步总包反应模型相比,有显著的改进。在此基础上,将简化机制的化学反应速率计算程序以用户自定义函数的形式加入Fluent软件,用一维几何模型验证了在商业计算流体力学(computational fluid dynamics,CFD)软件平台上使用简化机制进行SNCR反应流数值模拟的可行性,并进一步对沉降炉SNCR过程进行了CFD模拟,研究了温度、扩散、湍流等因素对SNCR的影响,模拟结果与实验吻合良好。
The trade-off of reliability and computation cost of chemical kinetic models is the major difficulty in selective non-catalytic reduction （SNCR） simulation. Based on AA mechanism, a detailed mechanism containing 60 species and 371 reactions for SNCR, a skeletal mechanism with 28 species and 97 reactions and further a reduced mechanism model of 12 major species and 8 global steps were established through sensitivity analysis and quasi-steady-state （QSS） assumption, which significantly reduced the computation cost. According to the computations using plug flow reactor model, the reduced mechanism is well consistent with the detailed over a wide range of temperature, residence time, ammonia/NO mole ratio and shows great improvement compared with the two step global kinetic model commonly used. The code of the reduced mechanism was then combined to Fluent, a commercial Computational Fluid Dynamic （CFD） software, by user defined function （UDF） interface to realize the simulation of SNCR reacting flow. A 1D model was first carried out to validate this method, and then the simulation of drop tube furnace was conducted to investigate the effect of temperature, mixing and turbulence. The simulation showed good consistency compared with the experiments.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2010年第14期68-76,共9页
Proceedings of the CSEE
基金
国家863高技术基金项目(2006AA06A304)~~
关键词
选择性非催化还原
机制简化
准稳态假设
反应
流
数值模拟
㈧--L|
selective non-catalytic reduction（SNCR）
mechanism reduction
quasi-steady-state（QSS） assumption
reacting flow
computational fluid dynamic （CFD） simulation
