Numerical simulations of cellular detonation diffraction in a stable gaseous mixture

详细信息    查看全文

• 作者：Jian Li^a ; Jianguo Ning^a ; Charles B. Kiyanda^b ; Hoi Dick Ng^b ; ^{hoing@encs.concordia.ca" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Detonations ; Diffraction ; Pulse detonation engine ; Stable mixture ; Adaptive mesh refinement (AMR)
• 刊名：Propulsion and Power Research
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：5
• 期：3
• 页码：177-183
• 全文大小：1281 K

文摘

In this paper, the diffraction phenomenon of gaseous cellular detonations emerging from a confined tube into a sudden open space is simulated using the reactive Euler equations with a two-step Arrhenius chemistry model. Both two-dimensional and axisymmetric configurations are used for modeling cylindrical and spherical expansions, respectively. The chemical parameters are chosen for a stable gaseous explosive mixture in which the cellular detonation structure is highly regular. Adaptive mesh refinement (AMR) is used to resolve the detonation wave structure and its evolution during the transmission. The numerical results show that the critical channel width and critical diameter over the detonation cell size are about 13±1 and 25±1, respectively. These numerical findings are comparable with the experimental observation and confirm again that the critical channel width and critical diameter differ essentially by a factor close to 2, equal to the geometrical scaling based on front curvature theory. Unlike unstable mixtures where instabilities manifested in the detonation front structure play a significant role during the transmission, the present numerical results and the observed geometrical scaling provide again evidence that the failure of detonation diffraction in stable mixtures with a regular detonation cellular pattern is dominantly caused by the global curvature due to the wave divergence resulting in the global decoupling of the reaction zone with the expanding shock front.