Abstract Cool flames play a critical role in ignition timing, burning rate, burning limits, engine knocking, and emissions in conventional and advanced combustion engines. This paper provides an overview of the recent progress in experimental and computational studies of cool flames. First, a brief review of low-temperature chemistry and classical studies of cool flames is presented. Next, the recent experimental and computational findings of cool flames in microchannels, microgravity droplet combustion, counterflow flames, and turbulent combustion environments are reviewed. The flammability diagrams of different low-temperature flames and their relations to hot flames in premixed and nonpremixed systems are discussed. The impact of cool flames on turbulent combustion and knock formation is also highlighted. Finally, future avenues in cool flame research, including the use of cool flames as a new platform for low-temperature kinetic model validation, are presented. It is concluded that the understanding and control of low-temperature combustion is critical for the development of future advanced engines and new fuels.

中文翻译：

---

冷火焰动力学

摘要 冷火焰在传统和先进内燃机的点火正时、燃烧速率、燃烧极限、发动机爆震和排放方面起着至关重要的作用。本文概述了冷火焰实验和计算研究的最新进展。首先，简要回顾了低温化学和冷火焰的经典研究。接下来，回顾了微通道中冷火焰、微重力液滴燃烧、逆流火焰和湍流燃烧环境中最近的实验和计算结果。讨论了预混和非预混系统中不同低温火焰的可燃性图及其与热火焰的关系。还强调了冷火焰对湍流燃烧和爆震形成的影响。最后，介绍了冷焰研究的未来途径，包括使用冷焰作为低温动力学模型验证的新平台。得出的结论是，对低温燃烧的理解和控制对于未来先进发动机和新燃料的发展至关重要。