Ignition of aluminum powders by electro-static discharge

Beloni, Ervin; Dreizin, Edward L.

doi:10.1016/j.combustflame.2010.01.010

Cited by 25 publications

(18 citation statements)

References 18 publications

(19 reference statements)

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“…A detailed description of the experimental set up used for this work was given in Refs. [29,30]. Figure 3 shows the apparatus including the Model 931 Firing Test System (FTS) by Electro-Tech Systems Inc., used to generate spark discharges.…”

Section: Spark Ignitionmentioning

confidence: 99%

Ignition of Nanocomposite Thermites by Electric Spark and Shock Wave

Shaw

Dlott

Williams

et al. 2014

Propellants Explo Pyrotec

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Nanocomposite 8Al ⋅ MoO3 thermite particles were prepared using arrested reactive milling and ignited using two experimental techniques. In spark ignition, a monolayer of powder was placed on a conductive substrate and heated in air by a pulsed electrostatic discharge. In shock ignition, an individual particle was targeted by a miniature, laser‐driven flyer plate accelerated to a speed in the range of 0.5–2 km s−1. In both experiments, time‐dependent optical emission produced by the ignited material was monitored and recorded. The heating rates achieved in the present experiments are on the order of 109−–1011 K s−1. These ignition methods result in a very fast combustion with characteristic burn times reduced by 1–3 orders of magnitude compared to the burn times measured previously for the same material ignited in the CO2 laser beam, where it was heated at a much lower rate of about 106−–107 K s−1. Ignition delays observed in both shock and spark ignition experiments are close to each other and vary in the range of 120–200 ns. The times of characteristic rapid increase in the optical emission of the ignited particles are also close to each other for the two experiments; however, these times are somewhat shorter (less than one μs) for the spark ignition tests compared to few μs observed for the shock initiated particles. Preliminary ideas enabling one to interpret the present results are discussed. This work establishes an approach for systematic studies of high rate ignition and respective combustion of nanocomposite reactive materials.

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Section: Spark Ignitionmentioning

confidence: 99%

Ignition of Nanocomposite Thermites by Electric Spark and Shock Wave

Shaw

Dlott

Williams

et al. 2014

Propellants Explo Pyrotec

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“…Similar to data presented in ref. [53] in which spark radius was determined from the size of the spark imprint left on a carbon-coated metal plate, the radius measured here was increasing at higher voltages.…”

Section: Spark Radius Measurementsmentioning

confidence: 79%

“…As in the previous work [51,53], the measured ESD current traces were curve-fitted using an expression for a decaying current for an L-R-C circuit connected in series [35], treating the L, R, and C values as adjustable parameters. The measurements and data processing were performed for both empty sample holder and sample holder filled with the powder.…”

Section: Electrical Characteristics Of Spark and Powder Layersmentioning

confidence: 99%

Mechanism of Electro-Static Discharge (ESD) Sensitivity of Reactive Powders and Its Mitigation

Dreizin¹,

Beloni²

2011

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“…Likewise, there has been no published safety characterization of nAl/H 2 O propellant mixtures. Safety characterization of aluminum and water is particularly important given the safety hazards of energetic compositions and in particular nanoscale metal powders [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Combustion of Nanoaluminum and Water Propellants: Effect of Equivalence Ratio and Safety/Aging Characterization

Sippel

Pourpoint

Son

2013

Propellants Explo Pyrotec

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The deflagration and combustion efficiency of 80 nm aluminum/ice (ALICE) mixtures with equivalence ratios of ϕ=1.0, 0.75, and 0.67 were experimentally investigated. We find that pressure exponent and burning rate vary little between these three mixtures, with the exponent varying only from 0.42 to 0.50 and burning rate at 6.9 MPa varying from 2.05 to 2.10 cm s−1. However, reducing the equivalence ratio from 1.0 to 0.67 surprisingly increases combustion efficiency from 70 % to 95 % with unburned aluminum agglomerates visible in electron microscopy photographs of 70 % combustion efficiency (ϕ=1.0) products. Our findings suggest that nanoaluminum/water combustion is diffusionally limited for all conditions considered. Aging tests on the propellant show that storage at −30 °C essentially stops the Al/H2O reaction such that little nanoaluminum degradation occurs after 200 days. Electrostatic discharge (ESD), shock initiation, and impact sensitivity tests indicate that the propellant is insensitive to ignition by these stimuli. Specifically, while neat nanoaluminum powders are highly ESD sensitive (ignition threshold 0.3–14 mJ), nAl/H2O mixtures are insensitive to ESD and have ignition thresholds in excess of 400 mJ. Likewise, nAl/H2O mixtures are insensitive to impact ignition, having an ignition threshold in excess of 2.2 m. Propellants containing 80 nm or larger average particle size aluminum were also found to be insensitive to shock initiation.

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Ignition of aluminum powders by electro-static discharge

Cited by 25 publications

References 18 publications

Ignition of Nanocomposite Thermites by Electric Spark and Shock Wave

Ignition of Nanocomposite Thermites by Electric Spark and Shock Wave

Mechanism of Electro-Static Discharge (ESD) Sensitivity of Reactive Powders and Its Mitigation

Combustion of Nanoaluminum and Water Propellants: Effect of Equivalence Ratio and Safety/Aging Characterization

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