摘要
为研究CO_(2)/O_(2)环境对柴油着火和燃烧特性的影响,以正庚烷为柴油表征燃料,利用CONVERGE计算了不同CO_(2)/O_(2)环境下正庚烷的着火和燃烧过程,并搭建了可视化定容燃烧弹试验平台进行了验证。使用高速摄影机记录了初始温度850 K,初始压力3 MPa,CO_(2)体积分数分别为35%、40%、50%和60%时正庚烷燃烧的自发光强度,利用CHEMKIN中定容均质反应器分析了CO_(2)物理和化学作用对着火的影响。研究结果表明:在CO_(2)体积分数35%时存在爆燃的现象,随着CO_(2)体积分数增长,着火延迟时间增长,着火位置远离喷嘴,稳态燃烧阶段火焰的长度和宽度也增大,CO_(2)体积分数在50%~60%之间时火焰自发光强度峰值明显下降;CO_(2)的物理作用抑制了着火,第三体作用对着火的促进作用大于直接参与反应对着火的抑制作用,造成CO_(2)的化学作用缩短了着火延迟时间,并且随着CO_(2)体积分数增大,化学作用对着火的促进作用更加明显。
In order to investigate the effect of CO_(2)/O_(2) environment on the ignition and combustion characteristics of diesel fuel,using n-heptane as the diesel surrogate fuel,the ignition and combustion process of n-heptane under different CO_(2)/O_(2) environments were calculated based on the computational fluid dynamics software CONVERGE.The optical constant volume combustion chamber was established to validate the model,and the nature flame luminosity of n-heptane combustion was recorded by high-speed camera.The initial temperature was 850 K,the initial pressure was 3 MPa,and the CO_(2) volume fractions were 35%,40%,50%and 60%.The reaction path of important radicals was calculated by the closed homogeneous reactor in CHEMKIN to analyze the physical and chemical effect of CO_(2) on ignition.The results show that,deflagration exists at 35%CO_(2) volume fraction.As the CO_(2) volume fraction increases,the ignition delay time increases,the ignition position is further away from the nozzle,and length and width of the steady-state flame also increases.The peak intensity of nature flame luminosity decreases significantly when the CO_(2) volume fraction is between 50%and 60%.The physical effect of CO_(2) suppresses the ignition,and the chemical effect of CO_(2) promotes the ignition due to the promotion of ignition by third body effect than the inhibition of ignition by direct chemical effect,and the chemical effect is strengthened with the increase of CO_(2) volume fraction.
作者
万源
刘永峰
毕贵军
刘海峰
张璐
WAN Yuan;LIU Yongfeng;BI Guijun;LIU Haifeng;ZHANG Lu(School of Mechanical-Electronic and Vehicle Engineering,Beijing University of Civil Engineering and Architecture,Beijing 102627,China;Singapore Institute of Manufacturing Technology,A*Star,Singapore 637662,Singapore;State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)
出处
《内燃机工程》
CAS
CSCD
北大核心
2023年第3期44-54,共11页
Chinese Internal Combustion Engine Engineering
基金
国家自然科学基金项目(51976007)
北京建筑大学研究生创新项目(PG2022128)
内燃机燃烧学国家重点实验室开放研究项目(K2023-04)。
