Micro Videographic Analysis of the Melt Layer of Self‐Deflagrating HMX and RDX

Washburn, Ephraim B.; Parr, T. P.; Hanson‐Parr, D. M.

doi:10.1002/prep.200800087

Cited by 12 publications

(4 citation statements)

References 9 publications

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“…Deflagrating explosives burn faster and more violently than non-explosive combustible materials, which require an external supply of oxygen to sustain the burning [15]. Laser-induced deflagrations have been investigated using laser pulses hundreds of microseconds or longer on HMX [16][17][18], TATB [16,17], RDX [18][19][20], and rocket propellants [21]. McGrane and Moore also investigated the effect of CW laser wavelength on the reaction of various explosives [22].…”

Section: Introductionmentioning

confidence: 99%

Laser‐induced Deflagration for the Characterization of Energetic Materials

Collins

Gottfried

2017

Prop., Explos., Pyrotech.

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Standard propellant and detonation tests typically performed to characterize the performance of energetic materials require large quantities of material (at least tens of grams) and can be expensive and time-consuming. This work introduces a method for characterizing the deflagration of energetic materials in a laboratory setting, using only 15-20 mg of energetic material. Temperature, energy release and emission signatures were measured and analyzed for the laser-induced deflagration of 8 different conventional military explosives. Graphite nanoparticles and micron-sized aluminum powder were added to the explosive compositions to investigate their effect on the emission signatures. A high-speed color camera recorded the deflagration events and was utilized as a fullcolor pyrometer to calculate the average temperatures and image hotspots; the temperatures maps were compared to those measured by conventional two-color pyrometry. The laboratory-scale method presented here can be applied to novel energetic materials under development that may be available only in limited quantities to evaluate their potential as propellants or reduced emission signature explosives prior to scale-up.

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Section: Introductionmentioning

confidence: 99%

Laser‐induced Deflagration for the Characterization of Energetic Materials

Collins

Gottfried

2017

Prop., Explos., Pyrotech.

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“…At the higher pressures, minimal expansion occurs leading to a more homogeneous structure. If this theory is true, then this data may be indirect evidence of a foam or froth layer similar to RDX and HMX [3]. Further data is needed to determine if the melt layer is formed by CL-20 and/or HTPB.…”

Section: Full Papermentioning

confidence: 97%

“…The result is a carbonaceous ash residue remains following decomposition of CL-20 [2]. A melt layer is present in both RDX and HMX flames and its structure is believed to influence the temperature and pressure dependence of the burning rate [3]. No experimental evidence has been reported that definitively shows a melt layer for CL-20 [4].…”

Section: Introductionmentioning

confidence: 99%

Influence of Particle Size on the Combustion of CL‐20/HTPB Propellants

Kalman¹,

Essel²

2017

Propellants Explo Pyrotec

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The effect of nitramine particle size on the combustion behavior of inert binder based propellants has been extensively studied for RDX and HMX, but not CL-20. Although materials such as RDX and HMX are useful for particular combustion applications, CL-20 has a greater potential to improve the oxygen balance and energy density of a propellant. The current work investigates the effect of CL-20 particle size on the combustion of CL-20/HTPB propellants down to submicrometer sizes. An influence of particle size on the burning rate and combustion mechanism is reported. The 30 micrometer formulation burning rate data showed evidence of convective burning specifically at higher pressures, but the pressure dependence was comparable to neat CL-20 at pressures below 8 MPa. A change in the combustion mechanism of the submicrometer formulation as a function of pressure was determined to be a result of the interaction of the propellant flame and the combustion residue. Data suggested that at low pressures diffusion in terms of active cooling was dominant for the submicrometer formulation. Higher pressure data for both the submicrometer and 3 micrometer formulations suggest the degree of active cooling is decreased as the burning rate pressure exponent is near 0.5 for both propellants. The indirect evidence for the presence of a melt layer for CL-20 propellants is discussed.

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“…Experiments have shown that many solid propellants exhibit a thin liquid layer with gaseous bubbles ("foam" layer), typically a few micrometers thick for AP-based propellants [14]. For HMX/RDX propellants at ambient pressure, the melt layer can be around 200 micrometers thick [43], while the gas flame thickness is around 5 millimeters. At higher pressure, both thicknesses decrease [44].…”

Section: General Modellingmentioning

confidence: 99%

Solid propellant combustion in the low Mach one-dimensional approximation: from an index-one differential-algebraic formulation to high-fidelity simulations through high-order time integration with adaptive time-stepping

Laurent¹,

Dupays²,

Davidenko³

et al. 2020

Preprint

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An unsteady one-dimensional model of solid propellant combustion, based on a low-Mach assumption, is presented and semi-discretised in space via a finite volume scheme. The mathematical nature of this system is shown to be differential-algebraic of index one. A high-fidelity numerical strategy with stiffly accurate singly diagonally implicit Runge-Kutta methods is proposed, and time adaptation is made possible using embedded schemes. High-order is shown to be reached, while handling the constraints properly, both at the interface and for the mass conservation in the gaseous flow field. Three challenging test-cases are thoroughly investigated: ignition transients, growth of combustion instabilities through a Hopf bifurcation leading to a limit cycle periodic solution and the unsteady response of the system when detailed gas-phase kinetics are included in the model. The method exhibits high efficiency for all cases in terms of both computational time and accuracy compared to first-and second-order schemes traditionally used in the combustion literature, where the time step adaptation is CFL-or variation-based.

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Micro Videographic Analysis of the Melt Layer of Self‐Deflagrating HMX and RDX

Cited by 12 publications

References 9 publications

Laser‐induced Deflagration for the Characterization of Energetic Materials

Laser‐induced Deflagration for the Characterization of Energetic Materials

Influence of Particle Size on the Combustion of CL‐20/HTPB Propellants

Solid propellant combustion in the low Mach one-dimensional approximation: from an index-one differential-algebraic formulation to high-fidelity simulations through high-order time integration with adaptive time-stepping

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