...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physical chemistry chemical physics: PCCP >The influence of thermal coupling and diffusion on the importance of reactions: The case study of hydrogen-air combustion
【24h】

The influence of thermal coupling and diffusion on the importance of reactions: The case study of hydrogen-air combustion

机译：热耦合和扩散对反应重要性的影响：氢空气燃烧的案例研究

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Detailed chemical kinetics mechanisms are usually developed on the basis of spatially homogeneous calculations, but utilized in the simulation of very complex physical models. A fundamental question is if the importance of reactions is determined solely by the temperature and the actual concentration set or if it is also influenced by the thermal and diffusion couplings present in the physical model. A 46-step detailed mechanism of hydrogen oxidation was studied at equivalence ratios 0.5, 1.0, 2.0, and 4.0. Six physical models were designed (homogeneous explosion, burner-stabilized and freely propagating laminar flames, with and without thermal coupling), which provided very similar concentration curves as a function of temperature, while the local sensitivity functions revealed that the couplings in these models were very different. The importance of the reactions in every model was investigated by the principal component analysis of the rate sensitivity matrix F (PCAF method), exploiting that the results of this method depend only on the concentrations and temperature. A fundamentally different method, the principal component analysis of the local sensitivity matrix S (PCAS method) was used to extract information on the importance of reactions from the sensitivity functions. The PCAF and PCAS methods selected identical reduced mechanisms at all conditions, which shows that these are equally effective methods for determining a minimal reduced mechanism. The good agreement between the results of the two methods in the case of all models demonstrated that the importance of reactions was independent of the physical model into which the mechanism had been embedded. Thermal coupling did not have any effect on the selection of the reduced mechanisms. The difference between the importance of reactions in explosions and flames was caused by the difference of the concentrations in the low-temperature regions and not by the presence of diffusion. The reduced mechanisms contained 15 to 28 reaction steps, depending on the equivalence ratio and the type of the model. All species were retained in models of the combustion of lean and stoichiometric mixtures, while species H2O2 could be eliminated at rich conditions. Description of near stoichiometric conditions required more reaction steps, while rich combustion could be described by few reactions. An overall reduced mechanism, applicable in a wide range of conditions, contained 31 reaction steps. Results of the PCAS method revealed the global similarity relations of the sensitivity matrices of adiabatic explosions. [References: 15]
机译：详细的化学动力学机制通常是在空间均质计算的基础上开发的，但可用于模拟非常复杂的物理模型。一个基本的问题是，反应的重要性是仅由温度和实际浓度设置决定的，还是由物理模型中存在的热和扩散耦合影响的。在当量比0.5、1.0、2.0和4.0下研究了46步详细的氢氧化机理。设计了六个物理模型（均匀爆炸，燃烧器稳定和自由传播的层流火焰，带有和不带有热耦合），它们提供了非常相似的浓度曲线随温度变化的函数，而局部灵敏度函数表明这些模型中的耦合是非常不一样。通过速率敏感度矩阵F（PCAF方法）的主成分分析，研究了每种模型中反应的重要性，并利用该方法的结果仅取决于浓度和温度。根本不同的方法是使用局部敏感度矩阵S的主成分分析（PCAS方法）从敏感度函数中提取有关反应重要性的信息。 PCAF和PCAS方法在所有条件下均选择相同的还原机制，这表明，这些方法是确定最小还原机制的同等有效方法。在所有模型的情况下，两种方法的结果之间的良好一致性表明，反应的重要性与嵌入该机理的物理模型无关。热耦合对简化机构的选择没有任何影响。爆炸和火焰中反应的重要性之间的差异是由低温区域浓度的差异引起的，而不是由扩散的存在引起的。简化的机制包含15到28个反应步骤，具体取决于当量比和模型的类型。所有种类都保留在稀薄和化学计量混合物的燃烧模型中，而H2O2种类可以在丰富的条件下消除。接近化学计量条件的描述需要更多的反应步骤，而富油燃烧可以通过很少的反应来描述。适用于各种条件的总体还原机理包含31个反应步骤。 PCAS方法的结果揭示了绝热爆炸敏感性矩阵的全局相似关系。 [参考：15]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号