CAREER: Promotion and Prevention of Flame Acceleration and Deflagration-to-Detonation Transition: from Fundamental Study to Practical Consideration

从亚音速（爆燃）到超音速（爆轰）的火焰加速问题在燃烧应用和消防安全方面是极其重要的。这种现象就是所谓的爆燃-爆轰过渡（DDT）。从实际考虑，DDT影响了无数的灾难，如每年夺去数百人生命的发电厂爆炸和矿难。另一方面，DDT可以以能量上最便宜的方式用于先进技术，如下一代高超音速飞机的微型燃烧室和脉冲爆震发动机。从基本观点来看，滴滴涕是一种有趣的现象，其应用范围从燃烧和惯性约束聚变到热核超新星。本项目将描述促进、控制或防止滴滴涕过程的机制。具体而言，将验证用更安全的替代燃烧制度取代节能制造中的危险爆炸的可能性。此外，还将开发一种用于消防安全和滴滴涕风险评估的新型预测工具。后者对于西弗吉尼亚州来说尤为重要，因为首席研究员所在的地区，该州的经济在很大程度上依赖于煤炭和页岩气采矿业。该项目的研究部分将与广泛的教育模块相结合，以提高学校和大学对先进燃烧研究的认识。特别是，教育模块将包括与美国宇航局赞助的西弗吉尼亚太空资助联盟合作组织的校园年度培训项目。教育模块也将被翻译成概念仓库——一个由nsf赞助的基于网络的教学工具。研究部分将包括计算工作和分析工作。它将致力于影响火焰加速和爆轰触发过程的几个因素之间的相互作用，如燃烧器的机械和热边界条件，燃烧不稳定性，湍流和可燃或惰性粉尘杂质。具体来说，将仔细研究燃料特性的局部变化对全局火焰传播情景的影响，并确定新发现的近音速准稳态爆燃状态的特性。这将决定这一制度是否受到粘性效应的控制，以及它是否可以作为引爆的替代方案。最后，对某煤矿甲烷-空气-粉尘火灾的演变过程进行量化。将确定火灾的演变如何取决于可燃或惰性粉尘的类型、大小、浓度和分布、燃料参数和采矿通道的几何形状。这将为新的预防性消防安全策略提供知识基础。

1554254 - AkkermanThe issues with flame acceleration from subsonic (deflagration) to supersonic (detonation) are extremely important in terms of combustion applications and fire safety. This phenomenon is the so-called deflagration-to-detonation transition (DDT). From the practical consideration, the DDT influences countless disasters such as explosions in power plants and mining accidents that claim hundreds of lives every year. On the other hand, the DDT can be employed, in the energetically cheapest manner, in advanced technologies such as micro-combustors and pulse-detonation engines of the next-generation hypersonic aircrafts. From the fundamental viewpoint, the DDT is an intriguing phenomenon with applications ranging from combustion and inertial confined fusion to Thermonuclear Supernovae. This project will characterize the mechanisms promoting, controlling or preventing the DDT process. Specifically, a possibility to replace a hazardous detonation in energy-efficient manufacturing with a safer alternative combustion regime will be verified. Additionally, a novel predictive tool for fire safety and DDT risk assessment will be developed. The latter is exceptionally important for West Virginia, the Principal Investigator's region where the state economy is significantly based on the coal and shale gas mining industry. The research component of this project will be integrated with an extensive educational module promoting awareness of advanced combustion research in schools and colleges. In particular, the educational module will include an on-campus annual training program organized in a partnership with the NASA-sponsored West Virginia Space Grant Consortium. The educational module will be also translated into the Concept Warehouse - an NSF-sponsored web-based instructional tool.The research component will include computational endeavors and analytical efforts. It will be devoted to the interplay between several factors influencing the processes of flame acceleration and detonation triggering such as mechanistic and thermal boundary conditions of a burner, combustion instabilities, turbulence, and combustible or inert dust impurities. Specifically, the influence of the local variations of the fuel properties on the global flame propagation scenario will be scrutinized, and the properties of a newly-found, near-sonic quasi-steady deflagration regime will be identified. It will be determined if this regime is controlled by viscous effects, and if it can be an alternative to a detonation. Finally, the evolution of a methane-air-dusty fire in a coal mine will be quantified. It will be identified how the fire evolution depends on the type, size, concentration and distribution of the combustible or inert dust, the fuel parameters and the geometry of a mining passage. This will provide the knowledgebase for the novel preventive fire safety strategies.