摘要
基于正庚烷、甲烷、乙烷、丙烷多组分混合物简化动力学机理耦合三维计算流体力学(computational fluid dynamics,CFD)数值模型,模拟研究高替代率时不同进气氛围(H_(2)、O_(2)组分)耦合废气再循环(exhaust gas recirculation,EGR)对天然气/柴油双燃料发动机低负荷工作过程的影响机理。研究表明:在不同EGR率下,进气掺氢会使缸内燃烧速率显著加快,OH活性基浓度明显升高,CH_(4)排放显著降低,但CO排放升高;进气掺氧后,缸压及瞬时放热率峰值、最大压力升高率、最高燃烧温度及OH活性基浓度均升高,碳烟、CO和CH_(4)后期氧化作用增强使其最终排放降低,但NO_(x)排放升高。在EGR率小于29%,掺氢比小于2.5%时,在实现较低CO、碳烟排放的同时能显著降低CH_(4)排放和NO_(2)/NO_(x)比例;高EGR率时,进气掺氧能降低CO、碳烟排放,并改善CH_(4)与NO_(x)排放之间的折中关系。
The effects of different intake atmosphere(H_(2),O_(2) composition)coupled with exhaust gas recirculation(EGR)on the mechanism of working process of natural gas/diesel dual fuel engine at low loads were studied based on three-dimensional computational fluid dynamics(CFD)simulation model,coupled with the simplified chemical kinetic mechanism of n-heptane/methane/ethane/propane multi-component mixture.Results show that under different EGR rates,the combustion rate in the cylinder and the concentration of OH active radical are increased significantly,and CH_(4) emissions are reduced significantly.But CO emissions are increased when H_(2) is added into the intake charge.Under different EGR rates,the peaks of cylinder pressure and instantaneous heat release rate,the maximum pressure rise rate,the maximum combustion temperature and the concentration of OH active radical are increased when O_(2) is added into the intake charge.At the same time,the post-oxidation of soot,CO and CH_(4) emissions are enhanced,so that the final emissions of soot,CO and CH_(4) are reduced,while NO_(x) emissions are increased.CH_(4) emissions and the ratio of NO_(2) to NO_(x) are significantly reduced while lower CO and soot emissions are achieved when the EGR rate is less than 29%and the volume mixing ratio of H_(2) is less than 2.5%.Adding O_(2) into the intake charge can reduce CO and soot emissions and improve the trade-off relationship between CH_(4) and NO_(x) emissions.
作者
陈贵升
魏峰
李冰
王震江
黄震
罗赢
CHEN Guisheng;WEI Feng;LI Bing;WANG Zhenjiang;HUANG Zhen;LUO Ying(Yunnan Key Laboratory of Internal Combustion Engine,Kunming University of Science and Technology,Kunming 650500,China;31638 Troops of the PLA,Kunming 650051,China)
出处
《内燃机工程》
CAS
CSCD
北大核心
2022年第2期1-11,共11页
Chinese Internal Combustion Engine Engineering
基金
国家自然科学基金项目(51866004)
云南省教育厅科学研究基金项目(2022Y157)。
关键词
双燃料发动机
进气氛围
废气再循环
燃烧
排放
dual-fuel engine
intake atmosphere
exhaust gas recirculation
combustion
emission
