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

1554254 -Akkerman火焰从亚音速（爆燃）加速到超音速（爆震）的问题在燃烧应用和消防安全方面极其重要。这种现象就是所谓的燃烧转爆轰（DDT）。从实际考虑，DDT影响了无数的灾难，如发电厂爆炸和矿难，每年夺去数百人的生命。另一方面，DDT可以以能量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，DDT是一个有趣的现象，其应用范围从燃烧和惯性约束聚变到热核超新星。本项目将介绍促进、控制或预防滴滴涕进程的机制。具体而言，将验证以更安全的替代燃烧制度取代节能制造中危险爆炸的可能性。此外，还将开发一种新的防火和滴滴涕风险评估预测工具。后者对西弗吉尼亚州尤为重要，西弗吉尼亚州是主要研究者所在的地区，该州经济主要依赖煤炭和页岩气开采业。该项目的研究部分将与一个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州空间赠款财团合作组织的校园年度培训计划。教育模块也将被翻译成概念仓库-一个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震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，可燃或惰性粉尘杂质。具体而言，燃料性质的局部变化对全球火焰传播的情况下的影响将被仔细检查，并确定一个新发现的，近音速准稳态爆燃制度的属性。将确定这种状态是否由粘性效应控制，以及它是否可以作为爆炸的替代方案。最后，在煤矿甲烷空气粉尘火灾的演变将被量化。将确定火灾演变如何取决于可燃或惰性粉尘的类型、尺寸、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.