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

West Virginia University Research Corporation, Morgantown WV

Investigators

Abstract

1554254 - Akkerman The 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.