热力参数对微尺度发动机燃烧特性影响机理分析  

Mechanism Analysis of Thermodynamical Parameter Effect on Micro Scale IC Engine Combustion Characteristics

作　　者：唐刚志[1] 张力[1] 尚会超[1] 杜宝程[1] 

机构地区：[1]重庆大学机械传动国家重点实验室,重庆400044

出　　处：《内燃机工程》2015年第2期103-110,共8页Chinese Internal Combustion Engine Engineering

基　　金：国家自然科学基金项目(51175530)

摘　　要：为了研究初始温度和压力对微尺度活塞式内燃机微燃烧特性的影响机理,采用层流有限速率模型和甲醇燃烧化学反应机理及动态网格技术,对其闭口热力系的瞬态预混层流燃烧过程进行动态多维仿真。结合化学反应机理温度敏感性分析和产物反应速率分析技术,从宏观和微观两个角度分析仿真结果,结果表明仿真结果与试验结果吻合较好。随着气体初始温度提高,自由活性基团浓度增加,以具有最大正温度敏感系数的反应为代表的基元反应速率增大,燃烧过程加快,缸内压力和温度增加。随着气体初始压力提高,由于H基竞争基元反应速率随压力增加的增加规律不同,使得部分曲轴转角下燃烧速率反而下降,缸内温度有所下降,但压力显著增加。从整体过程来看,燃烧速率随着初始压力的增大而增大。随着初始温度的增加,以具有最大生成排放物反应速率的反应为代表的基元反应速率增大,排放增加。To research influence mechanism of thermodynamical parameters on micro scale combustion characteristics in IC engine, series multidimensional numerical simulations were implemented. The laminar flow finite rate model, methanol combustion reaction mechanism and transient grid technology were adopted in simulation. The technologies of reaction mechanism temperature sensitivity analysis and reaction rate analysis of combustion products were employed to investigate the simulation results from macro and micro aspects. Results show that simulation results agree well with experimental results. With gas initial temperature increase, concentration of free active radical groups and elementary reaction rate increases, so combustion process accelerates, the cylinder pressure and temperature and the emissions also increase. However, with gas initial pressure increase, the combustion rate in part crank angles decreases because of H radical elementary reaction rate variation, causing the cylinder temperature lowering and the cylinder pressure increasing obviously. As a whole, the combustion rate increases with gas initial pressure increase and the emissions increase with its initial temperature increase.

关 键 词：内燃机 微尺度内燃机 微燃烧 化学反应机理 甲醇 

分 类 号：TK422[动力工程及工程热物理—动力机械及工程]