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Title: Fine Tuning the CJ Detonation Speed of a High Explosive products Equation of State

Abstract

For high explosive (HE) simulations, inaccuracies of a per cent or two in the detonation wave speed can result from not suficiently resolving the reaction zone width or from small inaccuracies in calibrating the products equation of state (EOS) or from variation of HE lots. More accurate detonation speeds can be obtained by ne tuning the equation of state to compensate. Here we show that two simple EOS transformations can be used to adjust the CJ detonation speed by a couple of per cent with minimal effect on the CJ release isentrope. The two transformations are (1) a shift in the energy origin and (2) a linear scaling of the speci c volume. The effectiveness of the transformations is demonstrated with simulations of the cylinder test for PBX 9502 starting with a products EOS for which the CJ detonation speed is 1 per cent too low.

Authors:
 [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1357103
Report Number(s):
LA-UR-17-23912
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; high explosive; CJ detonation speed; equation of state

Citation Formats

Menikoff, Ralph. Fine Tuning the CJ Detonation Speed of a High Explosive products Equation of State. United States: N. p., 2017. Web. doi:10.2172/1357103.
Menikoff, Ralph. Fine Tuning the CJ Detonation Speed of a High Explosive products Equation of State. United States. doi:10.2172/1357103.
Menikoff, Ralph. 2017. "Fine Tuning the CJ Detonation Speed of a High Explosive products Equation of State". United States. doi:10.2172/1357103. https://www.osti.gov/servlets/purl/1357103.
@article{osti_1357103,
title = {Fine Tuning the CJ Detonation Speed of a High Explosive products Equation of State},
author = {Menikoff, Ralph},
abstractNote = {For high explosive (HE) simulations, inaccuracies of a per cent or two in the detonation wave speed can result from not suficiently resolving the reaction zone width or from small inaccuracies in calibrating the products equation of state (EOS) or from variation of HE lots. More accurate detonation speeds can be obtained by ne tuning the equation of state to compensate. Here we show that two simple EOS transformations can be used to adjust the CJ detonation speed by a couple of per cent with minimal effect on the CJ release isentrope. The two transformations are (1) a shift in the energy origin and (2) a linear scaling of the speci c volume. The effectiveness of the transformations is demonstrated with simulations of the cylinder test for PBX 9502 starting with a products EOS for which the CJ detonation speed is 1 per cent too low.},
doi = {10.2172/1357103},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 5
}

Technical Report:

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  • Propagating detonation waves exhibit a curvature effect in which the detonation speed decreases with increasing front curvature. The curvature effect is due to the width of the wave profile. Numerically, the wave profile depends on resolution. With coarse resolution, the wave width is too large and results in a curvature effect that is too large. Consequently, the detonation speed decreases as the cell size is increased. We propose a modification to the products equation of state (EOS) to compensate for the effect of numerical resolution; i.e., to increase the CJ pressure in order that a simulation propagates a detonation wavemore » with a speed that is on average correct. The EOS modification also adjusts the release isentrope to correct the energy release.« less
  • A relatively simple pressure, volume, energy (PVE) equation of state has been developed to describe the adiabatic expansion of detonation products. Specific equations for ten explosives have been determined using detonation velocity and pressure data and results from metal acceleration experiments. The thermodynamic and hydrodynamic requirements placed upon this equation of state are discussed and a comparison of calculation and experimental results are presented.
  • To be useful, an equation of state for detonation products must allow rapid computation. The constraints applied by this requirement have surprising thermodynamic effects. Some of these are discussed here. A simple, complete equation of state is proposed, and its properties are discussed. With the form assumed here, all the useful integrals (except for the Riemann integral) can be written simply and explicitly, so the behavior of the important variables can be easily seen. The complete equation of state is calibrated for PBX9404 and PBX9501.