Experimental study of n-heptane ignition delay with carbon dioxide addition in a rapid compression machine under low-temperature conditions  

作　　者：GUANG HuanYu YANG Zheng HUANG Zhen LU XingCai 

机构地区：[1]Key Laboratory for Power Machinery and Engineering of Ministry of Education,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Chinese Science Bulletin》2012年第30期3953-3960,共8页

基　　金：supported by the Key Program of National Natural Science Foundation of China (50936004);Key Project of Science and Technology Committee of Shanghai (09DJ1400302)

摘　　要：The ignition delay of n-heptane homogeneous charge compression ignition(HCCI) combustion under high levels of carbon dioxide addition was quantitatively measured at elevated pressure from low to intermediate temperatures in a rapid compression machine.The experiments were conducted in the compressed temperature range 613-750 K.Both the compression ratio and fuel/air equivalence ratio were varied to investigate their effects on the ignition delay of n-heptane.Carbon dioxide was subsequently added to study the influence of the carbon dioxide level on the ignition delay of n-heptane under low-temperature conditions.It was found that carbon dioxide had different effects on the two-stages of ignition delay of n-heptane under low-temperature conditions:the concentration of carbon dioxide had little effect on the first-stage ignition time;a certain concentration of carbon dioxide accelerated the first-stage ignition but had a significantly larger impact on the second-stage ignition delay,thus increasing the overall ignition delay time.The results also showed that the first-stage ignition delay of n-heptane is only a function of temperature under low-temperature conditions.The mass of n-heptane in the combustible mixture,the equivalence ratio,and the pressure at the top dead center had little effect on the first-stage ignition time of n-heptane.The ignition delay of n-heptane homogeneous charge compression ignition （HCCI） combustion under high levels of carbon diox- ide addition was quantitatively measured at elevated pressure from low to intermediate temperatures in a rapid compression ma- chine. The experiments were conducted in the compressed temperature range 613-750 K. Both the compression ratio and fuel/air equivalence ratio were varied to investigate their effects on the ignition delay of n-heptane. Carbon dioxide was subsequently added to study the influence of the carbon dioxide level on the ignition delay of n-heptane under low-temperature conditions. It was found that carbon dioxide had different effects on the two -stages of ignition delay of n-heptane under low-temperature condi- tions： the concentration of carbon dioxide had little effect on the first-stage ignition time; a certain concentration of carbon dioxide accelerated the first-stage ignition but had a significantly larger impact on the second-stage ignition delay, thus increasing the overall ignition delay time. The results also showed that the first-stage ignition delay of n-heptane is only a function of tempera- ture under low-temperature conditions. The mass of n-heptane in the combustible mixture, the equivalence ratio, and the pressure at the top dead center had little effect on the first-stage ignition time of n-heptane.

关 键 词：点火延迟时间 二氧化碳 低温条件 压缩机 庚烷 实验 中间温度 点火时间 

分 类 号：TK16[动力工程及工程热物理—热能工程]