LES Study of stabilization mechanism in lifted ethanol spray flames
LES Study of stabilization mechanism in lifted ethanol spray flames
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乙醇喷射火焰稳定机理的LES研究
DOI：
10.1016/j.proci.2022.07.127
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发表时间：
2022
影响因子：
3.4
通讯作者：
R. Kurose
中科院分区：
文献类型：
--
作者：
Yong Hu;R. Kai;Jian Wen;Taichi Murakami;Yong Jiang;R. Kurose
本文对悉尼大学的O 'Loughlin和Masri （O 'Loughlin和Masri，《燃烧》）实验研究的稀释喷雾提升火焰进行了详细的数值研究。火焰2011)，重点是了解在喷雾影响下控制火焰稳定的机制。采用大涡模拟（LES）与有限速率化学动态增厚火焰（DTF）模型相结合的方法，对两种不同喷雾质量载荷和进口部分预混程度的乙醇火焰进行了数值模拟。采用化学爆炸模式分析（CEMA），有助于确定沿剪切层夹带点火过程的突出作用；该过程在下游部分预混反应区的火焰锚固中占主导地位。因此，一个较高的喷雾负荷可以加强夹带，导致更快的形成点火核。此外，在目前的火焰中，稳定点似乎持续在纯气体区域，具有最高的反应混合物分数和低的标量耗散率。结果表明，预混火焰能较好地表征主要受进口部分预混控制的前缘火焰结构，而上游演化的预燃混合气则适合于扩散火焰。此外，两种小火焰结构都无法捕获直接喷焰相互作用的下游结构，因为较大的液滴会产生较不均匀的混合物，且标量耗散率较高。这在稀薄的喷雾火焰中更为明显。
This work presents a detailed numerical investigation of dilute spray lifted flames experimentally studied by O’Loughlin and Masri at the University of Sydney (O’Loughlin and Masri, Combust. Flame 2011), with a focus on understanding the mechanism that governs flame stabilization under the influence of sprays. Two ethanol flames with varied spray mass loading and degree of partial-premixing at the inlet are simulated by large eddy simulation (LES) combined with the dynamically thickened flame (DTF) model with finite-rate chemistry. Chemical explosive mode analysis (CEMA) is employed which helps identify the prominent role of an entrainment-based ignition process along the shear layer; this process dominates the flame anchoring of the downstream partially-premixed reaction zone. Thus, a higher spray loading can intensify the entrainment, leading to a faster formation of ignition kernels. Furthermore, in present flames, the stabilization point appears to be sustained in a purely gaseous zone with the most reactive mixture fraction and low scalar dissipation rate. Results show that the premixed flamelet can adequately represent flame structures at the leading-edge that are primarily controlled by the inlet partial-premixing, whereas the upstream evolving pre-ignition mixtures are fit for the diffusion flamelet. Moreover, both flamelet configurations fail in capturing downstream structures with a direct spray - flame interaction because the larger droplets produce a less homogeneous mixture with a higher scalar dissipation rate. This is more evident in the lean spray flame.
影响因子：
4.4
作者：
V. N. Prasad;A. Masri;S. Navarro-Martinez;K. Luo
通讯作者：
V. N. Prasad;A. Masri;S. Navarro-Martinez;K. Luo