摘要
对某高速直喷柴油机的燃烧过程进行了多维仿真计算,研究了燃烧室形状和喷孔结构参数之间的匹配规律。通过变参数研究确定了燃烧室形状和喷孔结构参数之间的匹配规律。为了定量描述燃烧过程中燃油雾化、液体蒸发、油气混合的特性,建立了缸内平均湍流混合速率、燃油蒸气质量分数方差的中间特征参数,同时详细分析了不同当量比油气混合气在燃烧过程中的贡献率。从燃烧的宏观和微观角度综合分析了柴油机燃烧室形状与喷孔结构间的耦合作用机制。结果表明,对于所研究的机型,0.64口径比燃烧室匹配10孔喷油器的方案最优:预混过程好,燃烧速度快,后期扩散燃烧阶段过稀和过浓混合气参与燃烧的比例较小且预混与扩散燃烧放热情况差别小,放热情况更均匀。
Multi-dimensional simulation was applied for investigation of the combustion system of a high-speed direct injection diesel engine.The influence of the matching of combustion chamber and structural parameters of injection nozzle was analyzed comprehensively.Firstly,the law of the matching of combustion chamber and structural parameters of injection nozzle has determined by varying parameters study.In order to quantitatively describe the properties of fuel atomization,liquid evaporation and mixing of oil and gas,intermediate characteristic parameters of average rate of turbulent mixing and variance of the fuel vapor concentration were established,meanwhile a detailed analysis of the contribution rate on combustion of mixture in different equivalent ratio was showed.Comprehensive analysis the coupling mechanism of combustion chamber and structural parameters of injection nozzle from macro and micro perspective in combustion was acquired.The results showed that,for the model studied,the plan of a combustion chamber of 0.64 caliber ratio matching with a 10-hole injector was more appropriate.The premixing and combustion of the optimal scheme were better.In the diffusion combustion stage,the contribution of too thin and too rich mixture to combustion was small.The difference of the heat release rate between premixed and diffusion combustion was small,which meant a more homogeneous heat releasing process.
出处
《热科学与技术》
CAS
CSCD
北大核心
2012年第2期156-162,共7页
Journal of Thermal Science and Technology
基金
国家自然科学基金资助项目(51076008)
中央高校基本科研业务费专项资金资助项目(M11JB00300)
关键词
高速直喷柴油机
燃烧室形状
喷孔结构
匹配规律
high-speed direct injection diesel
combustion chamber geometry
structural parameters of injector
matching law
