A numerical support of leading point concept
A numerical support of leading point concept
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DOI：
10.1016/j.ijhydene.2022.05.140
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发表时间：
2022-06
影响因子：
7.2
通讯作者：
H. Lee;Peng Dai;M. Wan;A. Lipatnikov
中科院分区：
文献类型：
--
作者：
H. Lee;Peng Dai;M. Wan;A. Lipatnikov
本文报道了16个平面和一维复杂化学组成的贫氢（当量比为0.50或0.35）火焰在小尺度强湍流（Karlovitz数高达565）中传播的非定常三维直接数值模拟（DNS）数据。通过对实验数据的分析，比较了预混湍流火焰刷前缘和后缘在其传播过程中所起的作用。比较是基于以下考虑：（i）正（负）弯曲的反应区占主导地位的前（后，分别）边缘的预混湍流火焰刷和（ii）分子或原子氢的优先扩散的结果，在增加局部燃料消耗和热释放率，分别在正或负，弯曲的反应区。因此，湍流燃烧速度计算的钝化差分扩散效应的所有物种，无论是H2或H进行比较，评估所发挥的作用，由一个预混湍流火焰刷的前缘和后缘在其传播。通过分析的DNS数据，一个显着的增加，在当地的燃料消耗和热释放速率由于优先扩散的H2或H记录接近的领先或落后，分别研究火焰刷的边缘。然而，通过激活优先扩散单独为H2计算的湍流燃烧速度显着高于通过激活优先扩散单独为H计算的湍流燃烧速度。这一结果表明，在探索的湍流火焰刷的传播的前缘发挥了重要作用。
Unsteady three-dimensional Direct Numerical Simulation (DNS) data obtained from 16 statistically planar and one-dimensional, complex-chemistry, lean (equivalence ratio is equal to 0.50 or 0.35) hydrogen-air flames propagating in forced, intense, small-scale turbulence (Karlovitz number up to 565) are reported. The data are analyzed to compare roles played by leading and trailing edges of a premixed turbulent flame brush in its propagation. The comparison is based on the following considerations: (i) positively (negatively) curved reaction zones predominate at the leading (trailing, respectively) edge of a premixed turbulent flame brush and (ii) preferential diffusion of molecular or atomic hydrogen results in increasing the local fuel consumption and heat release rates in positively or negatively, respectively, curved reaction zones. Therefore, turbulent burning velocities computed by deactivating differential diffusion effects for all species with the exception of either H2or H are compared for assessing roles played by leading and trailing edges of a premixed turbulent flame brush in its propagation. By analyzing the DNS data, a significant increase in the local fuel consumption and heat release rates due to preferential diffusion of H2or H is documented close to the leading or trailing, respectively, edges of the studied flame brushes. Nevertheless, turbulent burning velocities computed by activating preferential diffusion solely for H2are significantly higher than turbulent burning velocities computed by activating preferential diffusion solely for H. This result indicates an important role played by the leading edge in the propagation of the explored turbulent flame brushes.