Effect of thermal properties on self-propagating fronts in reactive nanolaminates
Effect of thermal properties on self-propagating fronts in reactive nanolaminates
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DOI：
10.1063/1.3599847
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发表时间：
2011-07-01
影响因子：
3.2
通讯作者：
Weihs, Timothy P.
中科院分区：
文献类型：
--
作者：
Alawieh, Leen;Knio, Omar M.;Weihs, Timothy P.
研究了（1:1）Ni/Al多层体系中热扩散对火焰前缘动力学的影响。对导热模型进行了系统的改进，即通过纳入浓度、方向和温度依赖性的影响。所得到的导热模型被纳入由saloum和Knio[燃烧]开发的还原反应形式。火焰157(6),1154（2010）。恒定电导率和可变电导率模型的计算在轴向和法向前传播方面进行了对比。观察到各种电导率模型的预测之间存在显著差异，特别是在热和反应宽度方面。出乎意料的是，平均锋面传播速度的差异没有那么明显。最后，采用恒定导热系数和变导热系数模型对三维前传播进行了简单的计算实验。三维变电导率计算揭示了瞬态自旋反应的发生，这似乎与最近的实验观察一致，而当使用恒定电导率模型时，观察到稳定的前沿行为。因此，目前的经验表明，热扩散不稳定性可能在一些实验观察到的瞬态锋传播机制的开始和表现中起作用。(C) 2011年美国物理研究所。(doi: 10.1063/1.3599847)
The effects of thermal diffusion on flame front dynamics in a (1: 1) Ni/Al multilayered system are computationally investigated. A systematic refinement of the thermal conductivity model is performed, namely by incorporating the effects of concentration, direction, and temperature dependence. The resulting thermal conductivity models are incoporated into the reduced reaction formalism developed by Salloum and Knio [Combust. Flame 157(6), 1154 (2010]). Computations using constant and variable conductivity models are contrasted with each other, for axial and normal front propagation. Notable differences between the predictions of the various conductivity models are observed, particularly concerning the thermal and reaction widths. Differences in the average front propagation velocity are, unexpectedly, less pronounced. Brief computational experiments are finally conducted for 3D front propagation using constant and variable thermal conductivity models. The 3D variable-conductivity computations reveal the occurrence of transient, spinlike reactions that appear to be consistent with recent experimental observations, whereas stable front behavior is observed when a constant-conductivity model is used. Thus, the present experiences suggest that thermo-diffusive instabilities are likely to play a role in the onset and manifestation of some of the experimentally-observed transient front propagation regimes. (C) 2011 American Institute of Physics. [doi:10.1063/1.3599847]