摘要
为了研究初始参数对不同掺氢比CH4-H2混合燃料的均质压燃(HCCI)燃烧性能的影响,采用燃烧软件包Chemkin进行了数值模拟,并利用生成速率(ROP)分析法研究了掺氢比和过量空气系数对NO排放主导机理的影响.研究表明,掺氢比、压缩比、进气温度、空气过量系数通过影响发动机内的温度继而影响NOx排放;高掺氢比时可以通过适当降低压缩比和进气温度并增大空气过量系数从而控制NOx的排放.分析表明,掺氢比增大,热力型机理贡献率随之增大,占主导地位;过量空气系数增大,热力型机理贡献率减弱,N2O中间体机理贡献率增大,过量空气系数为2.5时,两种机理的主导地位大致相当.
To study the effect of initial parameters on homogeneous charge compression ignition(HCCI)combustion performance of CH4-H2 mixtures with different hydrogen ratios,numerical research was carried out through combustion software Chemkin,and the rate of production(ROP)analysis method was used to study the influence of hydrogen mixing ratio and excess air coefficient on the dominant mechanism of NO emission.The result shows that hydrogen ratio,compression ratio,inlet temperature and air excess coefficient affect NOx emission by affecting the temperature in the engine,and the NOx emission can be controlled by reducing the compression ratio and inlet temperature properly and increasing the air excess coefficient at high hydrogen ratios.The analysis shows that the contribution rate of thermodynamic mechanism increases with the increase of hydrogen ratios and decreases with the increase of the excess air coefficient,while the contribution rate of N2O intermediate mechanism increases with the increase of the excess air coefficient.When the excess air coefficient is 2.5,the dominant position of the two mechanisms is approximately the same.
作者
邓权威
林其钊
DENG Quanwei;LIN Qizhao(Department of Thermal Science and Energy Engineering,USTC,Hefei 230027,China;School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China)
基金
国家自然科学基金(51376171)资助.
