CAJ | 학술논문

通过修改SENKIN程序,建立起一个有质量交换和缸壁传热的9区化学反应动力学模型.以SKLE正庚烷简化模型作为燃烧反应动力学机理,利用该模型计算了发动机的主要燃烧参数和排放物含量.结果表明,该多区模型能够准确地模拟温度分层均质压燃发动机的燃烧和排放特性.在温度分层均质压燃发动机中,外核心区、壁面边界层和缝隙是CO和HC的主要来源.其中,在外核心区产生CO和HC是由于壁面边界层和缝隙内的未燃混合气在膨胀过程中流入该区被部分氧化或没有被继续氧化.NO_x主要来源于高温的内核心区.要同时获得高效燃烧和超低排放,应适当提高壁面温度.
통과수개SENKIN정서,건립기일개유질량교환화항벽전열적9구화학반응동역학모형.이SKLE정경완간화모형작위연소반응동역학궤리,이용해모형계산료발동궤적주요연소삼수화배방물함량.결과표명,해다구모형능구준학지모의온도분층균질압연발동궤적연소화배방특성.재온도분층균질압연발동궤중,외핵심구、벽면변계층화봉극시CO화HC적주요래원.기중,재외핵심구산생CO화HC시유우벽면변계층화봉극내적미연혼합기재팽창과정중류입해구피부분양화혹몰유피계속양화.NO_x주요래원우고온적내핵심구.요동시획득고효연소화초저배방,응괄당제고벽면온도.
A nine-zone model accounting for both mass exchange and heat loss was developed by modifying the SENKIN program. Combining with the SKLE simplified chemical kinetics model of n-heptane, the model was used to simulate the combustion and emissions of homogeneous charge compression ignition (HCCI) engine with charge-temperature stratification. The results showed that the simulation is able to reproduce the major combustion and emission characteristics of the experiments very well. In HCCI engine with charge-temperature stratification, the outer core zone, the boundary zone and the crevice zone are the source of CO and HC emissions. The CO and HC emissions in the outer core zone result from the partial-oxidation and unburned fuels which flow into the outer core zone from both the boundary zone and the crevice zone at the expand stroke. Most of NO_x emissions are produced in the inner core zones with higher temperature compared to the other zones. High efficiency combustion and extra low emissions are achieved simultaneously by increasing the wall temperature properly in HCCI engine with charge-temperature stratification.