Deflagration-to-detonation transition in an unconfined space

• Published in: Combustion and flame Vol. 195; pp. 163 - 169
• Main Authors: Koksharov, Andrey, Bykov, Viatcheslav, Kagan, Leonid, Sivashinsky, Gregory
• Format: Journal Article
• Language: English
• Published: New York Elsevier Inc 01-09-2018; Elsevier BV
• Subjects: Accelerating flames; Deflagration; Deflagration-to-detonation transition; Detonation; Feasibility; Flame retardants; Flame speed; Fluidized bed combustion; Positive feedback; Thermal runaway; Thermal runaway of fast flames; Accelerating flames; Deflagration-to-detonation transition; Thermal runaway of fast flames
• ISSN: 0010-2180; 1556-2921
• DOI: 10.1016/j.combustflame.2018.03.006

Whereas deflagration-to-detonation transition in confined systems is a matter of common knowledge, feasibility of the transition in unconfined space is still a matter of controversy. With a freely expanding self-accelerating spherical flame as an example, it is shown that deflagration-to-detonation transition in unconfined gaseous systems is indeed possible provided the flame is large enough. The transition is caused by positive feedback between the accelerating flame and the flame-driven pressure buildup, which results in the thermal runaway when the flame speed reaches a critical level.