摘要
针对高压直喷(HPDI)天然气双燃料低速船机的燃料喷射系统,研究了不同的天然气预喷策略对发动机燃烧特性及性能的影响,探究了适用于低速船机燃烧系统的天然气喷气规律。利用计算流体力学(CFD)软件Converge建立了HPDI天然气双燃料的单缸机仿真模型,与试验数据进行标定后,计算得到了不同预喷间隔及预喷比例下发动机燃烧性能和排放数据。分析计算结果表明,预喷策略的采用影响了燃烧过程中预混燃烧的比例,从而影响了燃烧放热相位及燃烧等容度。预喷比例相比预喷间隔对燃烧过程的影响更显著,后者在较大预喷比例下才会明显影响缸内燃烧放热过程。合理优化预喷策略可控制预混燃烧程度,从而同时改善NOx排放和油耗。不同的预喷策略使得缸内碳烟分布区域不同;与无预喷算例相比,采用预喷策略的算例最终碳烟排放量偏高。
For the fuel injection system of a pilot-ignited direct-injection natural gas engine,the influence of different natural gas pre-injection strategies on the combustion and emission characteristics of the engine was studied to explore the potential of natural gas pre-injection to improve the combustion system of low speed marine engines using a single-cylinder simulation model established by a Converge software.The combustion and emission data were verified by experiments and calculated at different pre-injection intervals and pre-injection ratios.Results show that the use of pre-injection strategy affects the proportion of premixed combustion in the combustion process,thus affecting the exothermic phase and isovolumetric combustion.Moreover,the pre-injection ratio has a more significant influence on the combustion process than the pre-injection interval,and the latter only affects the combustion exothermic process at a larger pre-injection ratio.In terms of emissions,the optimized pre-injection strategy can control the premixed combustion so as to achieve simultaneous improvement of NO x and fuel consumption.On the other hand,different pre-injection strategies allow different soot distributions in the cylinder.Compared with non-pre-injection solution,the use of pre-injection strategies leads to higher soot emissions.
作者
王解托
刘腾
董晶瑾
刘海峰
叶映
尧命发
WANG Jietuo;LIU Teng;DONG Jingjin;LIU Haifeng;YE Ying;YAO Mingfa(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China;China Shipbuilding Power Engineering Institute Co.,Ltd.,Shanghai 200120,China)
出处
《内燃机工程》
EI
CAS
CSCD
北大核心
2018年第5期73-79,共7页
Chinese Internal Combustion Engine Engineering
基金
船用低速工程(一期)研制项目(CDG01-KT0308)~~
关键词
天然气
预喷策略
微引燃
低速船机
CFD
natural gas
pre-injection strategy
pilot ignition
low-speed engine
CFD
