Temperature measurements of Al containing nano-thermite reactions using multi-wavelength pyrometry

Weismiller, Michael R.; Lee, J.G.; Yetter, Richard A.

doi:10.1016/j.proci.2010.06.094

Cited by 58 publications

(33 citation statements)

References 23 publications

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“…From experimental measurements of pressure rise times and flame speeds, the reaction front thickness in a burn tube has been calculated to be 10 mm thick, which lines up reasonably well with values of 10-40 mm measured from temperature rises observed in pyrometry experiments [5,14,18]. From this, we estimate a thermal gradient of 2.7 Â 10 5 K/m based on a temperature drop from 3000 K to 300 K over this distance.…”

Section: Conductionsupporting

confidence: 77%

Commentary on the heat transfer mechanisms controlling propagation in nanothermites

Egan

Zachariah

2015

Combustion and Flame

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a b s t r a c tThe combustion of nanothermites is a complex multiphase process that is still not well understood. One important aspect that is in need of further examination is the heat transfer mechanisms that drive combustion. Here we present some simple calculations to critically analyze the viability of conduction, convection, and radiation mechanisms of heat transfer as it relates to reaction propagation in nanothermites. While convection has generally been accepted as the critical mechanism for heat transfer, we show that the movement of hot gases cannot account for the required energy flow. Instead, it is illustrated that the movement of condensed phase material plays the critical role in heat transfer and should be accounted for in future models.Published by Elsevier Inc. on behalf of The Combustion Institute.

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Section: Conductionsupporting

confidence: 77%

Commentary on the heat transfer mechanisms controlling propagation in nanothermites

Egan

Zachariah

2015

Combustion and Flame

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“…However the data in Fig. 12 are not enough to prove graybody behavior, and other reasonable wavelength-dependent emissivities would create temperature uncertainties of ±150 K [29].…”

Section: Figure 11mentioning

confidence: 95%

“…12, if the emission originates from a graybody, where the emissivity is independent of wavelength, then a straight line will result and the slope will give the temperature. The slope would be hc/kT [29]. Figure 12 shows that both the nanosecond and microsecond processes give linear plots, and the nanosecond process is about 500K hotter than the microsecond process.…”

Section: Figure 11mentioning

confidence: 99%

“…Our latest study of the emission from shocked RM uses as an example the Al + CuO nanothermite reaction. The steady combustion of this nanothermite occurs at a temperature of 2680K [29]. The solid-state reaction mechanism involves Oxygen atom transport from ceramic CuO to metallic Al through an Al 2 O 3 oxide layer.…”

Section: Shock Initiation Of Nanotechnology Reactive Materialsmentioning

confidence: 99%

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Shock compression dynamics under a microscope

Dlott

2017

AIP Conference Proceedings

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Abstract.Our laboratory has developed a tabletop laser miniflyer launcher used for a wide variety of studies in the physical and chemical sciences. The flyers, typically 0.7 mm in diameter, can be used to shock microgram quantities of interesting materials. Frequently 100 shock experiments per day are performed. A microscope objective transmits the photon Doppler velocimeter (PDV) flyer plate diagnostic and various laser beams, and collects signals from the shocked materials that can be transmitted to video cameras, spectrographs, streak cameras, etc. In this paper I describe the flyer plate apparatus and then discuss three recent efforts: (1) Shock dissipation in nanoporous media; (2) Probing micropressures in shocked microstructured media; and (3) Shock initiation of nanotechnology reactive materials.

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“…Additional information on the research conducted on nanothermites can be found in Refs. [186][187][188][189][190][191][192][193]. …”

Section: Figure 137mentioning

confidence: 99%

Nano Engineered Energetic Materials (NEEM)

Dlott¹,

Eden²,

Girolami³

et al. 2011

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. The ARO Nano Engineered Energetic Materials (NEEM) MURI program has been exploring new methodologies for developing energetic material formulations with control of all constituents over a wide range of length scales from 1 nm to 1 mm and larger and employing the latest techniques in molecular self-assembly and supramolecular chemistry for synthesizing and assembling NEEMs. The synthetic efforts have been guided by theoretical calculations and dynamic performance testing methodologies that also operate on all length scales. This final report ABSTRACTThe ARO Nano Engineered Energetic Materials (NEEM) MURI program has been exploring new methodologies for developing energetic material formulations with control of all constituents over a wide range of length scales from 1 nm to 1 mm and larger and employing the latest techniques in molecular self-assembly and supramolecular chemistry for synthesizing and assembling NEEMs. The synthetic efforts have been guided by theoretical calculations and dynamic performance testing methodologies that also operate on all length scales. This final report provides a summary of the accomplishments. In particular, new methods to generate metal nanoclusters were developed that are stabilized against environmental degradation while preserving their high energy content. Rapid expansion supercritical solution processes were developed and applied to synthesize nanosized particulate oxidizers and energetic oxidizer shell/fuel core composites. Surface science and experimental chemistry methods were applied to study the structures and energy releasing reaction pathways of NEEMs. Unique diagnostic capabilities were developed and applied to study the fundamental mechanisms that underlie NEEM dynamic performance. Combustion mechanisms of various NEEMs, including nanothermites and nanoparticulate fuel/liquid oxidizer systems, were experimentally analyzed. The reactive and thermal characteristics of NEEMs were studied using large (billion atoms) multiscale simulations that couple quantum-mechanical calculations to molecular dynamics calculations. In particular, the stability, structure and energetics of metallic nanoparticles with a special focus on the relationships between particle size, shape and excess surface free energy were studied. A unified theory of ignition and combustion of aluminum particles for a wide range of sizes, from nano to meso scales was established. . 12, 777-787 (2010 (b) Papers published in non-peer-reviewed journals or in conference proceedings (N/A for none)18.00 Number of Papers published in peer-reviewed journals:Number of Papers published in non peer-reviewed journals:1. USC group, "Multibillion-atom simulations of nano-mechano-chemistry on petaflops computers," First

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Temperature measurements of Al containing nano-thermite reactions using multi-wavelength pyrometry

Cited by 58 publications

References 23 publications

Commentary on the heat transfer mechanisms controlling propagation in nanothermites

Commentary on the heat transfer mechanisms controlling propagation in nanothermites

Shock compression dynamics under a microscope

Nano Engineered Energetic Materials (NEEM)

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