TY - JOUR
T1 - Research on the initiation and wavefront evolution of diverging cylindrical detonations of acetylene and oxygen mixtures
AU - Li, Jian
AU - Ding, Chenyu
AU - Yang, Tianwei
AU - Lin, Genghao
AU - Ning, Jianguo
N1 - Publisher Copyright:
© 2024 Elsevier Masson SAS
PY - 2024/12
Y1 - 2024/12
N2 - The present study focuses on fundamental research about the transition from a planar detonation to a cylindrical detonation and the propagation of the diverging cylindrical detonation. We aim to figure out the mechanism of the transition and propagation of the diverging cylindrical detonation by analyzing the cellular pattern and critical initial pressure. The findings highlight that the successful detonation in a cylindrical chamber via transition through a straight channel is predominantly influenced by diffraction at the corners and the successive continuous reflections between the front and rear walls. Depending on the initial pressure, the initiation modes exhibit characteristics of subcritical, critical, and supercritical three-stage processes. Sustained propagation of cylindrical detonations necessitates increasing the number of cells to match the growth rate in the front region. Experimental investigations reveal two distinct modes of cell number increase: mild and violent. In the case of the former, cell number increase predominantly occurs on a scale of two to three times the characteristic cell size of the Chapman-Jouguet detonation. In contrast, a decaying Mach stem undergoes twisting and evolves into local kinks, leading to the development of new triple-wave points. The latter mode typically occurs near the limit, where cell increase primarily arises from randomly occurring local explosions, and operates on a scale of ten times the characteristic cell size or the chamber diameter. In addition, a numerical study of two-dimensional fundamental problems abstracted from the experiment is conducted to help interpret experimental results and reveal more about the physics of the problem.
AB - The present study focuses on fundamental research about the transition from a planar detonation to a cylindrical detonation and the propagation of the diverging cylindrical detonation. We aim to figure out the mechanism of the transition and propagation of the diverging cylindrical detonation by analyzing the cellular pattern and critical initial pressure. The findings highlight that the successful detonation in a cylindrical chamber via transition through a straight channel is predominantly influenced by diffraction at the corners and the successive continuous reflections between the front and rear walls. Depending on the initial pressure, the initiation modes exhibit characteristics of subcritical, critical, and supercritical three-stage processes. Sustained propagation of cylindrical detonations necessitates increasing the number of cells to match the growth rate in the front region. Experimental investigations reveal two distinct modes of cell number increase: mild and violent. In the case of the former, cell number increase predominantly occurs on a scale of two to three times the characteristic cell size of the Chapman-Jouguet detonation. In contrast, a decaying Mach stem undergoes twisting and evolves into local kinks, leading to the development of new triple-wave points. The latter mode typically occurs near the limit, where cell increase primarily arises from randomly occurring local explosions, and operates on a scale of ten times the characteristic cell size or the chamber diameter. In addition, a numerical study of two-dimensional fundamental problems abstracted from the experiment is conducted to help interpret experimental results and reveal more about the physics of the problem.
KW - Cellular structure
KW - Cylindrical detonation
KW - Detonation diffraction
KW - Gaseous detonation
KW - Open-shutter photography
UR - http://www.scopus.com/inward/record.url?scp=85206466946&partnerID=8YFLogxK
U2 - 10.1016/j.ast.2024.109668
DO - 10.1016/j.ast.2024.109668
M3 - Article
AN - SCOPUS:85206466946
SN - 1270-9638
VL - 155
JO - Aerospace Science and Technology
JF - Aerospace Science and Technology
M1 - 109668
ER -