TY - JOUR
T1 - Criticality for stabilized oblique detonation waves around spherical bodies in acetylene/oxygen/krypton mixtures
AU - Kasahara, Jiro
AU - Arai, Takakage
AU - Chiba, Shingo
AU - Takazawa, Kouki
AU - Tanahashi, Yu
AU - Matsuo, Akiko
N1 - Funding Information:
This study was supported by Industrial Technology Research Grant Programs from 2000 to 2001 from the New Energy and Industrial Technology Development Organization (NEDO) of Japan. We thank Mr. T. Yamazaki, Mr. N. Mikami, and Mr. S. Maruyama of Air Water, Inc.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2002
Y1 - 2002
N2 - We have experimentally studied self-sustained oblique detonation waves around projectiles as part of a fundamental investigation of the application of an oblique detonation wave engine and a high-efficiency detonation wave combustor as a power generator. In previous papers we used optical observation to clarify the fluid-dynamic structure of self-sustained oblique detonations stabilized around cone-nosed projectiles. In this study we investigated the criticality for detonation waves. The first expression of the criticality was a mean-curvature coefficient, a rate between a detonation cell width and a mean-curvature radius in which the normal velocity component was the Chapman-Jouguet (C-J) velocity, of 5.03. The mean-curvature coefficient was constant and did not depend on the type of fuel mixture (H2/O2/Ar or C2H2/O2/Ar), initial mixture pressure, projectile diameter, projectile velocity, or diluent mole fraction. We obtained a more accurate mean-curvature coefficient for stabilized oblique detonation around symmetric spherical bodies in highly krypton-diluted acetylene/oxygen mixtures that have extremely low C-J velocities. The mean-curvature coefficient of 7.8 was determined to be the most important value for stabilizing the self-sustained oblique detonation waves around multidimensional bodies. Based on experimental results obtained athigh- and low-projectile-velocity ranges, it may be concluded that a lower-velocity projectile can stabilize a self-sustained oblique detonation wave more effectively than can a higher-velocity one. In the high-projectile-velocity region, the experimental critical condition is inconsistent with Lee's detonation initiation theory. We propose a semiempirical criticality equation for the stabilization, which was the secondary expression of the criticality and identical with present and past experimental results.
AB - We have experimentally studied self-sustained oblique detonation waves around projectiles as part of a fundamental investigation of the application of an oblique detonation wave engine and a high-efficiency detonation wave combustor as a power generator. In previous papers we used optical observation to clarify the fluid-dynamic structure of self-sustained oblique detonations stabilized around cone-nosed projectiles. In this study we investigated the criticality for detonation waves. The first expression of the criticality was a mean-curvature coefficient, a rate between a detonation cell width and a mean-curvature radius in which the normal velocity component was the Chapman-Jouguet (C-J) velocity, of 5.03. The mean-curvature coefficient was constant and did not depend on the type of fuel mixture (H2/O2/Ar or C2H2/O2/Ar), initial mixture pressure, projectile diameter, projectile velocity, or diluent mole fraction. We obtained a more accurate mean-curvature coefficient for stabilized oblique detonation around symmetric spherical bodies in highly krypton-diluted acetylene/oxygen mixtures that have extremely low C-J velocities. The mean-curvature coefficient of 7.8 was determined to be the most important value for stabilizing the self-sustained oblique detonation waves around multidimensional bodies. Based on experimental results obtained athigh- and low-projectile-velocity ranges, it may be concluded that a lower-velocity projectile can stabilize a self-sustained oblique detonation wave more effectively than can a higher-velocity one. In the high-projectile-velocity region, the experimental critical condition is inconsistent with Lee's detonation initiation theory. We propose a semiempirical criticality equation for the stabilization, which was the secondary expression of the criticality and identical with present and past experimental results.
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U2 - 10.1016/S1540-7489(02)80344-3
DO - 10.1016/S1540-7489(02)80344-3
M3 - Conference article
AN - SCOPUS:0038156293
VL - 29
SP - 2817
EP - 2824
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
SN - 1540-7489
IS - 2
T2 - 30th International Symposium on Combustion
Y2 - 25 July 2004 through 30 July 2004
ER -