Numerical investigation of the effects of fuel variability on the dynamics of syngas impinging jet flames
Numerical investigation of the effects of fuel variability on the dynamics of syngas impinging jet flames
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DOI：
10.1016/j.fuel.2012.06.025
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发表时间：
2013
期刊：
影响因子：
7.4
通讯作者：
D. Martinez;Xi Jiang;C. Moulinec;D. Emerson
中科院分区：
文献类型：
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作者：
D. Martinez;Xi Jiang;C. Moulinec;D. Emerson
采用大涡模拟技术，研究了燃料可变性对氢气和合成气撞击火焰动力学的影响。在合成气混合物中CO和H2的组成是变化的，包括作为基线情况1的纯H2情况，情况2的20%CO与80%H2，情况3的40%CO与60%H2，以及情况4的20%CO与20%CO2和60%H2。撞击火焰构型的距离与喷嘴直径比H/d=20，燃料的入口速度为27 m/s。燃料从圆形喷嘴喷出，并与空气以非预混配置混合。结果表明，由于浮力和剪切层的不稳定性，火焰在主射流中形成了旋涡结构，壁面射流平行于撞击板运动，在不同的位置和强度上形成大尺度涡环，这与燃料成分有关。本文对一次射流和二次射流中的涡结构进行了全面的分析，沿着描述了它们对合成气火焰近壁传热和不稳定性的影响。还研究了污染物排放和物种形成，以便进一步了解未来更清洁燃烧系统的合成气燃烧特性。
Numerical simulations using the Large-eddy simulation technique is presented to study the effects of fuel variability on the dynamics of hydrogen and syngas impinging flames. The compositions of CO and H2are varied in a syngas mixture, including a pure H2case as the baseline Case 1, 20% CO with 80% H2for Case 2, 40% CO with 60% H2for Case 3, and 20% CO with 20% CO2and 60% H2for Case 4. The impinging flame configuration has a distance to nozzle diameter ratio of H/d=20 and the inlet velocity of the fuel is 27m/s. The fuel is issued from a circular nozzle and mixes with air in a non-premixed configuration. The results show that the flames develop vortical structures in the primary jet associated with the buoyancy and shear layer instability, and the wall jet progresses parallel to the impinging plate forming large-scale vortex rings at different locations and strengths as a consequence of the fuel compositions. A comprehensive analysis of vortical structures in the primary and secondary jet streams, along with a description of their effects on the near-wall heat transfer and instabilities of syngas flames is presented here. Pollutant emissions and species formations are also investigated in order to gain further insight into the syngas burning characteristics for future cleaner combustion systems.