Extensions to DSD theory: Analysis of PBX 9502 rate stick data

Steady Non-ideal Detonations in Cylindrical Sticks of Explosives

“…For lower detonation speeds, this extended theory gives results which are significantly different to the higher DSD theory (J. Bdzil, private communication), and which are in much better agreement with the results for front shapes and speeds from numerical simulations [14]. However, this shock-change equation based theory is essentially only a front propagation law, and one cannot reconstruct the flow field behind the shock (e.g.…”

“…corresponding to different charge diameters) do all lie close to one another or overlay, at least for sufficiently small curvatures [11][12] [13], indicating that the dynamics of curved detonation fronts in such explosives are, to leading order, well described by a single D n − κ law as predicted by the first order theory. Indeed, the D n − κ law determined from ratestick experiments for a given explosive can then be used to theoretically determine the shock front dynamics for the explosive in more complex geometries [5] [14]. For the more non-ideal explosives, however, such as PBXN 1111 and ANFOs, the D n − κ relations along individual shock fronts lie along different curves for different diameters, and these curves do not intersect or overlap [12][15] [16].…”

“…In order to increase the range over which the higher order theory is valid, an extended theory based on the exact shock-change equation is also given in [14], where the single unknown term in the equation is approximated using the higher-order DSD theory results. For lower detonation speeds, this extended theory gives results which are significantly different to the higher DSD theory (J. Bdzil, private communication), and which are in much better agreement with the results for front shapes and speeds from numerical simulations [14].…”

“…Aslam and co-workers [5][10] [14][16] performed several simulations in two-dimensional slab geometry. Their main interest was in validating or comparing with various aspects of DSD theory.…”

“…Their main interest was in validating or comparing with various aspects of DSD theory. However, a major result of this work was to show that for reasonably accurate results, numerical resolutions of more than about 50 numerical grid points in the reaction zone length are required [14]. Importantly, this raises severe questions regarding the validity of engineering style calculations, which typically only use 4-10 grid points in the reaction zone (e.g.…”