低氮环境下柴油机燃烧及排放特性数值模拟  

Numerical modeling of combustion and emission performances of diesel engines under low-nitrogen condition

作　　者：谭亲明 胡以怀[1] 张旭升[1] 张洪升[2] TAN Qinming;HU Yihuai;ZHANG Xusheng;ZHANG Hongsheng(Merchant Marine College,Shanghai Maritime University,Shanghai 201306,China;State Key Labratory of Internal Combution Engines,Tianjin University,Tianjin 300072,China)

机构地区：[1]上海海事大学商船学院,上海201306 [2]天津大学国家内燃机重点实验室,天津300072

出　　处：《武汉大学学报（工学版）》2018年第11期1009-1014,共6页Engineering Journal of Wuhan University

基　　金：国家自然科学基金重点项目(编号:51309149);上海海事大学博士研究生创新基金(编号:2015ycx080)

摘　　要：利用AVL—Fire软件建立4135ACa柴油机的三维数值模型，并对柴油机在低氮、无氮环境下的燃烧和排放特性进行了数值模拟计算，研究不同比例O2、N2、CO2的混合气作为柴油机进气时对其燃烧和排放性能的影响．研究表明：柴油机能够实现C02＆Oz环境下燃烧，O2浓度为60％时，燃烧严重滞后，燃烧过程主要在上止点后，燃烧不充分；但无氮燃烧能够有效实现NOx的零排放．当O2浓度为65％时，发火燃烧时刻与正常进气工况基本相同，且燃烧放热总量大于正常进气工况，但最高温度、最高压力及对外做功性能偏低，进一步提高O2浓度有利于提高其性能．在高浓度富氧的无氮燃烧中加入10％N2能够有效改善燃烧状况、提高经济性，但其NOx的排放成倍增加，通过低氮难以优化柴油机无氮燃烧的排放性能．调整喷油时刻或进气温度等能够进一步优化柴油机无氮燃烧性能．The 3D numerical model of 4135ACa diesel engine is established by AVL-Fire software to make simulative calculations of the combustion and emission performances on the diesel engine under the condition of low/no nitrogen. Studies have been made on the influences on the combustion and emission performances with the mixture gas of different proportions of O2/N2/CO2 as the air input. The research results show： Combustion is feasible under the condition of CO2 ＆ O2, but when the density is 60% ; it is seriously lagged behind and incomplete; and the burning process is mainly behind the top dead center. Zero discharge of NOx can effectively come true through nitrogen-free combustion. When O2 density is 65%, the ignition point is almost the same as that of the normal intake condition; and this condition has a larger total heat release; however, it has a relatively low highest temperature, highest pressure and external work. A further increase of O2 density will be favorable for boosting its performance. If 10% N2 is added into the oxygen-enriched nitrogen-free combustion, it is effective to improve the combustion and the eco- nomic efficiency, but the NOx emissions will multiply; so it is still a difficulty to optimize the performances of nitrogen-free combustion with low nitrogen density. Such measures as adjusting oil injection point or the intake temperature will further optimize the performances of nitrogen-free combustion.

关 键 词：柴油机 低氮 无氮 燃烧 排放 数值模拟 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]