Effects of thermal expansion on Taylor dispersion-controlled diffusion flames
Effects of thermal expansion on Taylor dispersion-controlled diffusion flames
复制标题
热膨胀对泰勒色散控制扩散火焰的影响
DOI：
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发表时间：
2021
影响因子：
1.3
通讯作者：
Adam D. Weiss
中科院分区：
文献类型：
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作者：
Prabakaran Rajamanickam;Adam D. Weiss
进行了理论分析，以研究由于放热而导致的气体膨胀对管流中演变的不稳定扩散火焰的影响，其中反应物的混合由泰勒分散过程控制，从而扩展了先前基于热扩散模型开发的理论。首先表明，在大于径向扩散时间的情况下，在第一近似中，由气体膨胀引起的压力梯度与驱动流动的主要压力梯度相比较小，这表明对背景速度剖面的修正较小。对于伯克-舒曼火焰，求解了速度分量的修正以及浓度、温度和密度等主阶混合变量。由于有效泰勒扩散系数对气体密度的依赖性，观察到热扩散模型的预测存在定量和有时定性的偏差。
A theoretical analysis is developed to investigate the effects of gas expansion due to heat release on unsteady diffusion flames evolving in a pipe flow in which the mixing of reactants is controlled by Taylor's dispersion processes thereby extending a previously developed theory based on the thermo-diffusive model. It is first shown that at times larger than radial diffusion times, the pressure gradient induced by the gas expansion is, in the first approximation, small in comparison with the prevailing pressure gradient driving the flow, indicating that corrections to the background velocity profile are small. The corrections to the velocity components along with the leading-order mixing variables such as the concentrations, temperature and density are solved for a Burke–Schumann flame. Due to the dependence of the effective Taylor diffusion coefficients on the gas density, quantitative and sometimes qualitative departures in predictions from the thermo-diffusive model are observed.