Scaling of detonation velocity in cylinder and slab geometries for ideal, insensitive and non-ideal explosives. (21st May 2015)

• Record Type: Journal Article
• Authors: Jackson, Scott I.; Short, Mark
• Is Part Of: Journal of fluid mechanics. Volume 773(2015:Jun.)
• Page Start: 224
• Page End: 266
• Publication Date: 2015-05-21
• Subjects: compressible flows, -- detonation waves; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2015.240
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract : Experiments were conducted to characterize the detonation phase-velocity dependence on charge thickness for two-dimensional detonation in condensed-phase explosive slabs of PBX 9501, PBX 9502 and ANFO. In combination with previous diameter-effect measurements from a cylindrical rate-stick geometry, these data permit examination of the relative scaling of detonation phase velocity between axisymmetric and two-dimensional detonation. We find that the ratio of cylinder radius ( $R$ ) to slab thickness ( $T$ ) at each detonation phase velocity ( $D_{0}$ ) is such that $R(D_{0})/T(D_{0})<1$ . The variation in the $R(D_{0})/T(D_{0})$ scaling is investigated with two detonation shock dynamics (DSD) models: a lower-order model relates the normal detonation velocity to local shock curvature, while a higher-order model includes the effect of front acceleration and transverse flow. The experimentally observed $R(D_{0})/T(D_{0})$ ( ${<}1$ ) scaling behaviour for PBX 9501 and PBX 9502 is captured by the lower-order DSD theory, revealing that the variation in the scale factor is due to a difference in the slab and axisymmetric components of the curvature along the shock in the cylindrical geometry. The higher-order DSD theory is required to capture the observed $R(D_{0})/T(D_{0})$ ( ${<}1$ ) scaling behaviour for ANFO. An asymptotic analysis of the lower-order DSD formulation describes the geometric scaling of the detonation phase velocity between the cylinder and slab geometries as the detonation phase velocity approaches the Chapman–Jouguet value.