Development of a new reduced hydrogen combustion mechanism with NOx and parametric study of hydrogen HCCI combustion using stochastic reactor model
Development of a new reduced hydrogen combustion mechanism with NOx and parametric study of hydrogen HCCI combustion using stochastic reactor model
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DOI：
10.1016/j.enconman.2016.11.021
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发表时间：
2017-01
影响因子：
10.4
通讯作者：
R. Maurya;N. Akhil
中科院分区：
文献类型：
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作者：
R. Maurya;N. Akhil
氢气是一种潜在的替代燃料和可再生燃料，可用于均质充量压燃（HCCI）发动机，以实现更高的效率和CO、未燃碳氢化合物以及CO2和CH 4等温室气体的零排放。在这项研究中，一个详细的氢氧化机理与NOx的开发，将额外的物种和NOx反应，现有的氢燃烧机制（10种和40个反应）。本研究中使用的详细氢燃烧机理包括39个物种和311个反应。从详细机理出发，采用有向关系图（DRG）方法，建立了由30个物种和253个反应组成的简化机理。利用随机反应器模型对HCCI发动机进行了模拟，并与实验数据进行了对比。对HCCI发动机中氢气燃烧和NOx生成的主要反应进行了灵敏度分析。还进行了途径分析，以分析不同温度下的重要反应途径。结果表明，H2 + HO 2 [=] H + H2 O2和O2 + NNH [=] N2 + HO 2分别是氢均质压燃燃烧和NOx生成中最重要的反应。采用改进的化学动力学模型对HCCI燃烧过程进行了详细的参数研究。通过改变发动机转速（1000-3000 rpm）、进气温度（380-460 K）和压缩比（16-18），在不同的相对空燃比（λ）下，对不同的发动机工况进行了数值模拟。结果表明，随着压缩比的增加，HCCI的工作范围扩大。研究了进气温度、发动机转速和当量比对缸内压力和放热率的影响。在所有试验条件下，观察到最大热效率为46%，最大燃烧效率为98%。同时对NOx排放进行了参数研究，发现NOx排放从高负荷到低负荷呈指数下降。
Hydrogen is a potential alternative and renewable fuel for homogenous charge compression ignition (HCCI) engine to achieve higher efficiency and zero emissions of CO, unburned hydrocarbons as well as other greenhouse gases such as CO2and CH4. In this study, a detailed hydrogen oxidation mechanism with NOxwas developed by incorporating additional species and NOxreactions to the existing hydrogen combustion mechanism (10 species and 40 reactions). The detailed hydrogen combustion mechanism used in this study consists of 39 species and 311 reactions. A reduced mechanism consisting 30 species and 253 reactions was also developed by using directed relation graph (DRG) method from detailed mechanism. Developed mechanisms were validated with experimental data by HCCI engine simulation using stochastic reactor model. Sensitivity analysis was performed to identify the most important reactions in hydrogen combustion and NOxformation in HCCI engine. Pathway analysis was also performed to analyze the important reaction pathways at different temperatures. Results revealed that H2 + HO2 [=] H + H2O2 and O2 + NNH [=] N2 + HO2 are the most significant reactions in the hydrogen HCCI combustion and NOxformation respectively. Detailed parametric study of HCCI combustion was conducted using developed chemical kinetic model. Numerical simulations are performed at different engine operating condition by varying engine speed (1000–3000 rpm), intake air temperature (380–460 K), and compression ratio (16–18) at different relative air fuel ratios (λ). The HCCI operating range was determined for different compression ratios and results show that operating range expands with increase in compression ratio. The effect of intake temperature, engine speed and equivalence ratio on cylinder pressure and heat release rate were investigated. Maximum thermal efficiency of 46% and maximum combustion efficiency of 98% was observed among all the test conditions. Parametric study of NOxemissions was also conducted and it was found that NOxemissions decrease exponentially from higher to lower engine loads.