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The paper proposes a technique for assessment of critical conditions determining the possibility of deflagration-to-detonation transition (DDT) inside confined vessels filled with hydrogen-based gaseous mixtures. It is known that the chocked flame regime is the necessary step to the deflagration-to-detonation transition in channels. Here the analysis of the chocked flame structure allows defining its stability conditions on the basis of a simple parametric study. The evolution of chocked flame in the stable mode leads to additional flame acceleration finalised with DDT taking place at the flame front. The unstable mode determines the formation of the quasi-steady flame propagating with near-sonic speed. It is found that the proposed parametric study allows assessment of the critical conditions with a fine enough accuracy for the case of smooth channels. However, in flame acceleration inside obstructed channels, the stable mode of chocked flame propagation is limited in time, due to the multidimensionality of the flow patterns formed inside the channel. As a result, one does not observe DDT at the flame front under such conditions. The main scenario of DDT developed inside an obstructed channel is self-ignition in the region of deceleration of supersonic flow by the obstacles. Due to this, to obtain good enough predictions of DDT possibilities inside obstructed channels one should jointly apply the parametric analysis of the chocked flame stability with the geometric criterion (such as the Thomas criterion). This paper demonstrates that such an approach provides good enough predictions of DDT limits for a given mixture, its state and geometry of the vessel.
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International Seminar on Fire and Explosion Hazards (9; 2019; Saint Petersburg, Russia). Proceedings of the Ninth International Seminar on Fire and Explosion Hazards [Электронный ресурс]. Vol. 1: 21-26 April 2019, Saint Petersburg, Russia / Peter the Great St. Petersburg Polytechnic University, Autonomous Non-Profit Organization "Fire and Explosion Safety", Gefest Holding Ltd ; [edited by A. Snegirev [et al.]. — Электрон. текстовые дан. (1 файл : 118 Мб). — Saint Petersburg, 2019. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/k19-45.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/k19-45>.
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