Front shock behavior of stable curved detonation waves in rectangular-cross-section curved channels

Abstract

The propagation of curved detonation waves of gaseous explosives stabilized in rectangular-cross-section curved channels is investigated. Three types of stoichiometric test gases, C2H4 + 3O2, 2H 2 + O2, and 2C2H2 + 5O2 + 7Ar, are evaluated. The ratio of the inner radius of the curved channel (r i) to the normal detonation cell width (λ) is an important factor in stabilizing curved detonation waves. The lower boundary of stabilization is around ri/λ = 23, regardless of the test gas. The stabilized curved detonation waves eventually attain a specific curved shape as they propagate through the curved channels. The specific curved shapes of stabilized curved detonation waves are approximately formulated, and the normal detonation velocity (Dn)-curvature (κ) relations are evaluated. The Dn nondimensionalized by the Chapman-Jouguet (CJ) detonation velocity (DCJ) is a function of the κ nondimensionalized by λ. The Dn/DCJ-λκ relation does not depend on the type of test gas. The propagation behavior of the stabilized curved detonation waves is controlled by the Dn/D CJ-λκ relation. Due to this propagation characteristic, the fully-developed, stabilized curved detonation waves propagate through the curved channels while maintaining a specific curved shape with a constant angular velocity. Self-similarity is seen in the front shock shapes of the stabilized curved detonation waves with the same ri/λ, regardless of the curved channel and test gas. © 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.