摘要
分别采用CFD耦合柴油/天然气/氢气(DNH)三燃料化学动力学机理以及CHEMKIN化学动力学分析的手段,对柴油/天然气(DN)双燃料发动机掺H2的燃烧特性、重要组分及排放物生成过程进行数值模拟.研究表明:在保持引燃柴油量不变的条件下,将缸内燃料热值5%的天然气(NG)替换为H2,燃烧过程中关键自由基OH的浓度峰值会增加了88%;而OH的强氧化性促使CH4的氧化速率增加,HC排放下降为91.8%,CH2O和CO的生成速率及峰值浓度增加,CH2O排放减少为97.5%,CO排放降低为23%,碳烟排放下降为19.3%,由于缸内燃烧温度增加,导致NOx排放增加为51%;掺H2之后,缸内压力升高率增加,燃烧持续期缩短,累积放热量及瞬时放热率峰值增加,缸内温度峰值增加,温度峰值相位提前.
A CFD model in coupling with diesel/natural gas/hydrogen(DNH)three-fuel chemical kinetics mechanism and the CHEMKIN chemical kinetic analysis were used to investigate the effects of hydrogen as an additive in diesel/natural(DN)gas dual-fuel engine on combustion characteristics,important species and emissions generation process.Results show that,under the condition of constant amount of pilot diesel,replacing natural gas(NG)by H2 at an amount having 5%of the total heating value of fuel causes an 88%increase of the peak concentration of OH radical during the combustion process.The strong oxidation of OH radical promotes the oxidation rate of CH4,leading to a 91.8%drop in HC pollutant emission.The production rate and peak concentration of CH2O and CO increase.The pollutant emission of CH2O,CO and soot decreases by 97.5%,23%and 19.3%respectively,but NOx increases by 51%due to the increased in-cylinder temperature.Furthermore,the addition of H2 causes an increase of the cylinder pressure rise rate,the cumulative heat release and the peak temperature,a reduction of the combustion duration and an advance of peak temperature phase.
作者
张韦
常少月
陈朝辉
陈贵升
Zhang Wei;Chang Shaoyue;Chen Zhaohui;Chen Guisheng(Yunnan Key Laboratory of Internal Combustion Engine,Kunming University of Science and Technology,Kunming 650500,China)
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2020年第1期34-41,共8页
Transactions of Csice
基金
国家自然科学基金资助项目(51665023,51666007)
关键词
柴油
天然气
掺氢燃烧
化学动力学
diesel
natural gas
combustion of H2 addition
chemical kinetics
作者简介
张韦,博士,教授,E-mail:koko_575@aliyun.com;通信作者:陈朝辉,博士,副教授,E-mail:chenzhaohuiok@sina.com.
