Mechanisms performance and pressure dependence of hydrogen/air burner-stabilized flames
Mechanisms performance and pressure dependence of hydrogen/air burner-stabilized flames
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DOI：
10.1051/mmnp/2018046
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发表时间：
2018
影响因子：
2.2
通讯作者：
V. Bykov;V. Gubernov;U. Maas
中科院分区：
文献类型：
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作者：
V. Bykov;V. Gubernov;U. Maas
氢气燃烧的动力学机制是研究最多的燃烧系统。这是由于燃烧过程的机制极其重要，即它作为碳氢化合物燃烧系统的所有机制中的子机制存在。因此，氢火焰的详细方面仍在积极研究中，例如在高压、不同热损失强度和局部当量比等条件下。为此，燃烧器稳定火焰构型是通过改变燃烧器的间隔距离、压力、温度和混合物成分来研究化学动力学不同方面的有效工具。在本工作中，重新审视了扁平多孔塞式燃烧器火焰构型。氢气/空气燃烧系统考虑了详细的分子传输（包括热扩散）和 8 种不同的化学反应机制。进行了详细的数值研究，以找出化学动力学对稳定性损失和火焰振荡动力学的作用。作为主要成果，发现/证明了关键值的结果，例如临界质量流量、加权振荡频率和吹出速度，随着压力的增加几乎随机分布。因此，这些参数可以被认为是独立的，并且可以用于改进和验证非定常动力学的化学动力学机制。
The kinetic mechanism of hydrogen combustion is the most investigated combustion system. This is due to extreme importance of the mechanism for combustion processes, i.e. it is present as a sub-mechanism in all mechanisms for hydrocarbon combustion systems. Therefore, detailed aspects of hydrogen flames are still under active investigations, e.g. under elevated pressure, under conditions of different heat losses intensities and local equivalence ratios etc. For this purpose, the burner stabilized flame configuration is an efficient tool to study different aspects of chemical kinetics by varying the stand-off distance, pressure, temperature of the burner and mixture compositions.In the present work, a flat porous plug burner flame configuration is revisited. A hydrogen/air combustion system is considered with detailed molecular transport including thermo-diffusion and with 8 different chemical reaction mechanisms. Detailed numerical investigations are performed to single out the role of chemical kinetics on the loss of stability and on the dynamics of the flame oscillations. As a main outcome, it was found/demonstrated that the results of critical values, e.g. critical mass flow rate, weighted frequency of oscillations and blow-off velocity, with increasing the pressure scatter almost randomly. Thus, these parameters can be considered as independent and can be used to improve and to validate the mechanisms of chemical kinetics for the unsteady dynamics.