Forced ignition of turbulent spray flames
Forced ignition of turbulent spray flames
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DOI：
10.1016/j.proci.2016.08.044
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
E. Mastorakos
中科院分区：
文献类型：
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作者：
E. Mastorakos
本文综述了火焰在喷雾中通过火花的作用或局部热沉积引发火焰，以及随后的火焰在液滴均匀和非均匀分散以及湍流存在时的发展的知识现状。这些工艺在各种应用中非常重要，例如燃气轮机点火(再点火)和与可燃液体雾相关的安全。本文从燃烧室的整体尺度出发，对火焰的初始发展、球形火焰和边缘火焰的演化以及喷雾火焰的着火进行了综述。通过实验和直接数值模拟讨论了在整个燃烧器点火的不同阶段决定点火过程成败的因素，同时也评估了建模的努力。燃料的挥发性、液滴大小、总的油空比和预蒸发程度是区分喷雾点火和气态火焰点火的重要因素，以及由随机液滴位置引起的额外波动，以及这可能如何影响建模和火焰演化。火焰在层流和湍流喷雾中的传播机理是决定点火成败的关键因素之一。并对今后的研究提出了建议。
This paper reviews the current state of knowledge on the initiation of a flame in a spray through the action of a spark or through local deposition of heat, and the subsequent flame development, in uniform and non-uniform dispersions of droplets and in the presence of turbulent flow. These processes are of importance in various applications such as gas turbine ignition (relight) and safety related to flammable liquid mists. The review focuses on the initial kernel development, the evolution of a spherical or edge flame, and the ignition of the spray flame when viewed at the whole combustor scale. The factors that determine success or failure of the ignition process at the various phases of the overall burner ignition are discussed through experiments and Direct Numerical Simulations, while modelling efforts are also assessed. The fuel volatility, droplet size, overall fuel-to-air ratio, and the degree of pre-evaporation are the important factors that distinguish spray ignition from gaseous flame ignition, and the extra fluctuations introduced by the random droplet locations, and how this may affect modelling and flame evolution, are highlighted. The flame propagation mechanism in laminar and turbulent sprays is one of the key aspects determining overall ignition success. Suggestions for future research are discussed.