Effect of Heterogeneities on the Reaction-zone of a Propagating Detonation Wave

Technical Report · Wed Jul 01 04:00:00 EDT 2020

DOI:https://doi.org/10.2172/1643894· OSTI ID:1643894

Menikoff, Ralph ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Reactive burn models for propagating detonation waves in an explosive are based on the ZND (Zel'dovich-Von Neumann-Doring) theory. A key property of the ZND theory, which leads to self-sustaining detonation waves, is a sonic point relative to the front in the reaction zone. Moreover, burn models assume the explosive is a homogeneous material. This assumption is used for plastic-bonded explosives, even though they are heterogeneous materials. The heterogeneities are accounted for only with an empirical burn rate. Furthermore, the reaction-zone width can be less than the length scale of heterogeneities. This raises the question of the effect of heterogeneities on the reaction zone. In particular, whether the reaction zone can be steady and have a well defined sonic point. To examine this question we focus on PBX 9501 since there is data on the grain-binder heterogeneities and on the reaction-zone velocity time history of a steady planar detonation wave. Using pseudo-mesoscale 1-D simulations, we examine the effect of a detonation wave transversing explosive and binder segments of random length. The simulations show that the reaction zone is quasi-steady with only short wavelength small amplitude variations in the detonation wave pressure and speed. The main effect of the heterogeneities is to introduce noise in the pressure and velocity fields that propagates into the Taylor wave behind the detonation. This is consistent with the scatter in the reaction-zone measurements for PBX 9501.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: 89233218CNA000001
• OSTI ID: 1643894
• Report Number(s): LA-UR--20-24842
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
ZND theory
detonation wave
heterogeneous explosive
reaction zone