Measuring thermal diffusivities of high explosives by the flash method. [LX-04, LX-07, LX-09, LX-10, LX-14, and RX-03-BB]

Cornell, R.H.; Johnson, Gary L.

doi:10.2172/6371283

Cited by 5 publications

(8 citation statements)

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“…In another experimental study, Cornell and Johnson [5] measured the thermal conductivity of several β-HMX-based PBXs for 228 K� T �350 K. While their data are not directly comparable to ours, they did report a pronounced decrease of the thermal conductivity with increasing temperature.…”

Section: Resultscontrasting

confidence: 56%

“…Experimentally, a few studies were performed on β-HMX polycrystals/powders (sometimes porous) that did not resolve the effect of crystal orientation [6,8,27]. Others worked with β-HMX-based plasticbonded explosives (PBXs) [5,8]. Hanson-Parr and Parr [6] studied the effect of temperature on the thermal conductivity of pressed powders for 293.15 K� T �433.15 K. Lawless et al [8] performed experimental determination of thermal conductivity of pressed powder β-HMX and some β-HMX-based PBXs at T ¼300 K and 441 K. Cornell and Johnson [5] measured thermal conductivity of several β-HMX-based PBXs for 228 K� T �350 K. Each of these studies will be discussed further in Sec.…”

Section: P (Gpa)mentioning

confidence: 99%

“…Here, we apply the G-K approach as described in Ref. [25] to obtain the thermal conductivity tensor of β-HMX for pressures 0.1 MPa� P �30 GPa and temperatures 300 K� T �900 K. These intervals extend significantly the regions of T; P ð Þ space considered in the other studies [5,6,8,18].…”

Section: P (Gpa)mentioning

confidence: 99%

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Thermal conductivity tensor of β‐HMX as a function of pressure and temperature from equilibrium molecular dynamics simulations

Pereverzev

Sewell

2023

Propellants Explo Pyrotec

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We apply the Green-Kubo (G-K) approach to obtain the thermal conductivity tensor of β-1, 3,5,3,5, as a function of pressure and temperature from equilibrium molecular dynamics (MD) simulations. Direct application of the G-K formula exhibits slow convergence of the integrated thermal conductivity values even for long (120 ns) accumulated simulation times. To partially mitigate this slow convergence, we apply a recently implemented numerical procedure that involves physically justified filtering of the MD-calculated G-K heat current and fitting the integrated time-

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Section: Resultscontrasting

confidence: 56%

Section: P (Gpa)mentioning

confidence: 99%

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Thermal conductivity tensor of β‐HMX as a function of pressure and temperature from equilibrium molecular dynamics simulations

Pereverzev

Sewell

2023

Propellants Explo Pyrotec

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“…44 These modeling results are largely consistent with recent determinations using density functional theory 18 and other FFs. 19 All reported experimental measurements for pure TATB were performed on polycrystalline pressed-powder samples in the 1970s and include the determinations of Faubion, 68 Cornell and Johnson, 69 and Baytos. 70 To aid comparison across these diverse states and sample types, Figure 12 shows the present best-fit conductivity values along with literature values from MD simulations based on the TATB FF and from the available experiments.…”

Section: Resultsmentioning

confidence: 99%

Fourier-like Thermal Relaxation of Nanoscale Explosive Hot Spots

2021

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Hot spots are local regions of high temperature that are widely considered to govern explosive initiation. Hot spot dynamics rests on a delicate balance between heat generation due to chemical reactions and heat loss through thermal conduction, making accurate determinations of the conductivity under extreme conditions a key component of predictive explosive models. We develop here an approach to directly determine the thermal transport properties of explosive hot spots with realistic initial structures through a combination of molecular dynamics (MD) and diffusive heat equation (HEq) modeling. Effective thermal conductivity values are determined by fitting HEq models to MD predictions of long timescale hot spot relaxation. The approach is applied to model hot spots in the molecular crystalline explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) for a range of shock strengths and two limiting cases for impact orientation. Isotropic and anisotropic HEq models yield similar results, despite TATB exhibiting some of the largest and most anisotropic thermal conductivity values for explosive near normal conditions. The conductivity is found to be a strong function of density, which parametrically captures dependence on temperature, pressure, and material state. The associated root-mean-square errors of the fitted HEq models are approximately 5% of MD predicted final equilibrium temperatures. The conductivity values determined here for TATB hot spots are considerably larger than those used in a prior hot spot criticality study, which may significantly impact predictions for critical hot spot sizes. The approach provides a convenient foundation for determining the effective thermal conductivity for hot spot problems in other explosives and directly yields information on reasonable approximations that might be taken in higher-level models for those materials.

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“…This hydrogen bonding is a major factor in TATB's high activation energy for thermal decomposition (60 kcal/mol, compared to 40 -50 kcal/mol for other explosives) (5). Hydrogen bonding also contributes to the high thermal diffusivity of TATB, which is 1.6 to 3 times that of other explosives (6). This high thermal diffusivity causes shock induced "hot spots" to cool before they can react and grow (7).…”

Section: Introductionmentioning

confidence: 99%

ALE3D Statistical Hot Spot Model Results for LX-17

Nichols¹,

Tarver²,

McGuire³

2004

AIP Conference Proceedings

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The Statistical Hot Spot shock initiation and detonation reactive flow model for solid explosives in the ALE3D hydrodynamic computer code provides physically realistic descriptions of: hot spot formation; ignition (or failure to ignite); growth of reaction (or failure to grow) into surrounding particles; coalescence of reacting hot spots; transition to detonation; and self-sustaining detonation. The model has already successfully modeled several processes in HMX-based explosives, such as shock desensitization, that can not predicted by other reactive flow models. In this paper, the Statistical Hot Spot model is applied to experimental embedded gauge data on the insensitive triaminotrintrobenzene (TATB) based explosive LX-17.

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Measuring thermal diffusivities of high explosives by the flash method. [LX-04, LX-07, LX-09, LX-10, LX-14, and RX-03-BB]

Cited by 5 publications

References 0 publications

Thermal conductivity tensor of β‐HMX as a function of pressure and temperature from equilibrium molecular dynamics simulations

Thermal conductivity tensor of β‐HMX as a function of pressure and temperature from equilibrium molecular dynamics simulations

Fourier-like Thermal Relaxation of Nanoscale Explosive Hot Spots

ALE3D Statistical Hot Spot Model Results for LX-17

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