The effect of dilution on the diffusive-thermal instability of the rich premixed hydrogen deflagration
The effect of dilution on the diffusive-thermal instability of the rich premixed hydrogen deflagration
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DOI：
10.1016/j.ijhydene.2019.02.185
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发表时间：
2019-04
影响因子：
7.2
通讯作者：
V. Gubernov;V. Bykov;U. Maas
中科院分区：
文献类型：
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作者：
V. Gubernov;V. Bykov;U. Maas
研究了浓淡预混氢氧火焰的动力学特性。在一维框架内对非定常火焰传播问题进行了数值处理，并建立了详细的化学动力学和混合平均分子扩散模型。通过研究自由传播火焰的临界压力、脉动周期和脉动幅度等脉动不稳定性的特征，研究了混合物稀释对自由传播火焰扩散热脉动不稳定性的影响。氦气、氮气和Ar的稀释对火焰不稳定性的影响在数量上是相似的：即振荡开始的临界压力基本降低，而振荡周期增加。研究还表明，通过降低绝热火焰温度而不是通过改变物种分子扩散来影响中性稳定性边界。观测到的振荡开始的临界压力的降低和稳定火焰传播区域的稳定性边界对热化学系统参数的敏感性，为进一步的化学动力学机制的实验验证开辟了新的视角。
The study focuses on the dynamics of rich premixed diluted hydrogen-oxygen flames. The problem of unsteady flame propagation is treated numerically within a 1D framework with a detailed model for the chemical kinetics and mixture averaged molecular diffusion. The effect of mixture dilution on the onset of the diffusive-thermal pulsating instabilities of freely propagating flames is investigated by studying the characteristics of the pulsating instabilities e.g. critical pressure of the onset, period and amplitude of pulsations. The dilution with helium, nitrogen and argon shows quantitatively a similar effect on the flame instability: namely, the critical pressure for the onset of oscillations is essentially reduced, while the period of oscillations increases. It is also shown that the neutral stability boundary is affected to a leading order through the reduction of the adiabatic flame temperature rather than by modification of the species molecular diffusion. The observed reduction of the critical pressure for the onset of oscillations and the sensitivity of the stability boundary of a steady flame propagation regime to the thermo-chemical system parameters open new perspectives for additional experimental validation of mechanisms of chemical kinetics.