A simple one-step chemistry model for partially premixed hydrocarbon combustion
A simple one-step chemistry model for partially premixed hydrocarbon combustion
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DOI：
10.1016/j.combustflame.2006.08.001
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发表时间：
2006-10-01
影响因子：
4.4
通讯作者：
Williams, Forman A.
中科院分区：
文献类型：
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作者：
Fernandez-Tarrazo, Eduardo;Sanchez, Antonio L.;Williams, Forman A.
这项工作探讨了具有统一反应级数的一步不可逆阿累尼乌斯动力学在部分预混烃燃烧的数值描述中的适用性。采用平面预混火焰计算来选择反应热 q、活化温度 T-a 和指前因子 B 三个模型参数。可以看出，富燃料燃烧中需要引入 q 随当量比 phi 的变化来描述部分燃料氧化对放热量的影响，从而导致所有碳氢化合物在 phi > 1 时存在通用的线性变化 q(phi)。该模型还采用可变的活化温度 T-a(phi) 来模拟浓火焰和极稀火焰中基础化学的变化。由此产生的化学描述能够在整个可燃极限范围内准确地再现稀释和未稀释火焰的传播速度。此外，甲烷-空气逆流扩散火焰的计算用于在非预混合条件下测试所提出的化学反应。该模型不仅准确预测了熄灭时的临界应变率，而且还给出了氧气泄漏的近乎熄灭火焰，从而克服了一步阿伦尼乌斯动力学的已知预测局限性。 (c) 2006 年燃烧研究所。由爱思唯尔公司出版。保留所有权利。
This work explores the applicability of one-step irreversible Arrhenius kinetics with unity reaction order to the numerical description of partially premixed hydrocarbon combustion. Computations of planar premixed flames are used in the selection of the three model parameters: the heat of reaction q, the activation temperature T-a, and the preexponential factor B. It is seen that changes in q with equivalence ratio phi need to be introduced in fuel-rich combustion to describe the effect of partial fuel oxidation on the amount of heat released, leading to a universal linear variation q(phi) for phi > 1 for all hydrocarbons. The model also employs a variable activation temperature T-a(phi) to mimic changes in the underlying chemistry in rich and very lean flames. The resulting chemistry description is able to reproduce propagation velocities of diluted and undiluted flames accurately over the whole flammability limit. Furthermore, computations of methane-air counterflow diffusion flames are used to test the proposed chemistry under nonpremixed conditions. The model not only predicts the critical strain rate at extinction accurately but also gives near-extinction flames with oxygen leakage, thereby overcoming known predictive limitations of one-step Arrhenius kinetics. (c) 2006 The Combustion Institute. Published by Elsevier Inc. All rights reserved.