天然气发动机燃烧不稳定性分形特征分析  

Fractal Characteristics of Combustion Instability for a Natural Gas Engine

作　　者：丁顺良 刘津津 牟俊超 崔超[1] 宋恩哲[3] 杨福源[4,5] DING Shunliang;LIU Jinjin;MOU Junchao;CUI Chao;SONG Enzhe;YANG Fuyuan(School of Mechanical and Power Engineering,Zhengzhou University,Zhengzhou 450001,China;Shanghai Marine Diesel Engine Research Institute,Shanghai 201108,China;College of Power and Energy Engineering,Harbin Engineering University,Harbin 150001,China;State Key Laboratory of Automotive Safety and Energy,Tsinghua University,Beijing 100084,China;School of Vehicle and Mobility,Tsinghua University,Beijing 100084,China)

机构地区：[1]郑州大学机械与动力工程学院,郑州450001 [2]上海船用柴油机研究所,上海201108 [3]哈尔滨工程大学动力与能源工程学院,哈尔滨150001 [4]清华大学汽车安全与节能国家重点实验室,北京100084 [5]清华大学车辆与运载学院,北京100084

出　　处：《西安交通大学学报》2022年第12期23-32,共10页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(51906225);汽车安全与节能国家重点实验室开放基金资助项目(KF2030);河南省高等学校重点科研资助项目(20A470001)。

摘　　要：为了揭示点火正时θ_(sit)对天然气发动机燃烧不稳定性的影响规律,在低负荷工况下,针对不同θ_(sit)工况进行试验,利用多重分形和多尺度熵方法对指示平均有效压力p_(imep)、放热量Q时间序列进行分析,并利用p_(imep)的循环变动系数P_(CCV)进行验证,对天然气发动机燃烧不稳定性的分形特征进行了定性、定量研究。结果表明:天然气发动机燃烧过程呈现出一定的分形特征,随着θ_(sit)提前,Hurst指数变化差值和奇异谱宽度先增大后减小,P_(CCV)先减小后增大,多尺度熵随尺度因子的增加而减小,燃烧不稳定性的分形复杂度和反持续相关性先增强后减弱,表明存在一个最优θ_(sit)使得天然气发动机的燃烧稳定性达到最佳。并且,对θ_(sit)影响天然气发动机燃烧不稳定性的原因进行了研究,为改善天然气发动机稀燃稳定性提供了理论依据。To reveal the pattern of influence of θ_(sit)on combustion instability for natural gas engine,experiments are carried out under low load condition with different θ_(sit).The multi-fractal and multiscale entropy methods are applied to analyze the experimental p_(imep) and Q time series,and the P_(CCV) of p_(imep) are used to verify the results.The fractal characteristics of combustion instability for the natural gas engine is qualitatively and quantitatively analyzed.Results show that the combustion process for natural gas engine exhibits certain fractal characteristics.With θ_(sit)being advanced,the difference value of Hurst index and the width of singular spectrum increase at first and then decrease;the _(CCV) decreases at first and then increases;the multiscale entropy decreases asτincreases.The fractal complexity and anti-persistence correlation of combustion instability enhance at first and then weaken,indicating that there is an optimal θ_(sit)which makes the combustion stability of natural gas engine reach its best.In addition,the analysis on the causes of θ_(sit)affecting the combustion instability provides a theoretical basis for improving the lean-burn stability of natural gas engine.

关 键 词：天然气发动机 燃烧不稳定性 点火正时 多重分形 多尺度熵 

分 类 号：TK464[动力工程及工程热物理—动力机械及工程]