On AlO Emission Spectroscopy as a Diagnostic in Energetic Materials Testing

Peuker, Jennifer Mott; Lynch, Patrick T.; Krier, Herman; Glumac, Nick

doi:10.1002/prep.201200144

Cited by 46 publications

(12 citation statements)

References 59 publications

(84 reference statements)

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“…Previous studies also showed the predominance of AlO emission when Al plasma interacted with ambient air, which is consistent with the standard heat of formation being strongly exothermic for AlO and strongly endothermic for AlN[40]. During Al combustion, other molecules such as Al 2 O and AlO 2 can also be formed as intermediates, but they do not have strong emission bands in the visible region and are therefore not observed in this experiment[41].…”

supporting

confidence: 89%

Impact of oxygen chemistry on the emission and fluorescence spectroscopy of laser ablation plumes

Hartig

Brumfield

Phillips

et al. 2017

Spectrochimica Acta Part B: Atomic Spectroscopy

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supporting

confidence: 89%

Impact of oxygen chemistry on the emission and fluorescence spectroscopy of laser ablation plumes

Hartig

Brumfield

Phillips

et al. 2017

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…Note that different optical signatures, e.g., pulses filtered to select the AlO molecular emission or, alternatively, as is done here, focusing on the black body radiation, may have different durations and thus imply different absolute burn times (Peuker et al, 2013). Currently, there is no preferred method that can be used universally, so care should be taken when comparing burn times reported in studies using different optical signatures of the burning particles.…”

Section: Particle Burn Timesmentioning

confidence: 93%

Combustion of Mechanically Alloyed Al∙Mg Powders in Products of a Hydrocarbon Flame

Corcoran

Wang

Aly

et al. 2014

Combustion Science and Technology

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Burn times and temperatures were measured optically for a set of mechanically alloyed Al·Mg powders injected into a laminar and a turbulent air-acetylene flame. Magnesium concentrations varied from 10 to 53 mole%; particle sizes were in the range of 1-50 µm. Emission from the burning particles at 700 nm, 800 nm, and 900 nm was captured using three filtered photomultiplier tubes. The burn times were correlated with particle sizes using measured statistical distributions for both times and sizes. The measured trends for burn times, t, as a function of particle size, d, for all alloys were approximated by a t = a·d n law, where the exponent n varied from 0.6 to 1. Shorter burn times were measured in more turbulent flows; respectively, the values of pre-exponent, a, decreased and exponent, n, increased slightly with an increased level of turbulence. An increase in Mg concentration led to longer burn times for the alloy particles for all flame conditions. For all compositions, alloy particles burned longer than similarly sized Al particles except for the alloy with the smallest concentration of Mg, Al 0.9 Mg 0.1 , for which particles less than ∼4 µm burned faster than similarly sized Al. This effect was observed for laminar and turbulent flames. The optically measured temperatures were lower for Al 0.47 Mg 0.53 alloy (∼2400 K) compared to ∼2700-2800 K obtained for other alloys. Turbulent mixing resulted in a slight increase in the measured temperature.

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“…The present results, however, indicate that strong multiple scattering of the light in two-phase metal flames makes spatial interpretation of the emission spectra unreliable. At best, the emission measurements can only indicate the maximum temperature in the flame, since emission intensity is strongly weighted to higher temperatures [25].…”

Section: Molecular Emission Spectra Of Alomentioning

confidence: 99%

Emission and laser absorption spectroscopy of flat flames in aluminum suspensions

Soo

Goroshin

Glumac

et al. 2017

Combustion and Flame

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Imaging emission spectroscopy, spatially resolved laser-absorption spectroscopy, and particle image velocimetry (PIV) are applied to a flat flame stabilized in a suspension of micron-sized aluminum. The results from the combination of diagnostics are used to infer the combustion regime of the particles and to estimate the characteristic combustion time of the suspension. It is observed that the reaction zone of the flame in stoichiometric aluminumair suspensions exhibits strong self-reversal of the atomic aluminum emission lines. These lines also exhibit high optical depths in both emission and absorption spectroscopy. The strong self-reversal and high optical depths indicate high concentrations of aluminum vapor within the reaction zone of the flame at multiple temperatures. These features provide evidence of the formation of vapor-phase micro-diffusion flames around the individual particles in the suspension. In aluminum-methane-air flames, the lack of self-reversal and lower optical depths of the aluminum atomic lines indicate the absence of vapor-phase micro-diffusion flames, and point to a more heterogeneous, and likely kinetically-controlled, particle combustion regime. The reaction zone thickness is estimated from the spatially resolved profiles of aluminum resonance lines in both absorption and emission through the flame. The emission measurements yield a reaction zone thickness on the order of 1.7±0.3 mm in aluminum-air flames, and the absorption measurements yield a thickness on the order of 2.3±0.5. It is demonstrated that the combination of the combustion zone thickness measurement, flame temperatures determined from molecular AlO emission spectra, and particle velocity measurements from the PIV diagnostic permits an estimation of the burning time in the suspension. The burning time in stoichiometric aluminum-air suspensions using the suite of diagnostics is estimated to be on the order of 0.7 milliseconds.

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On AlO Emission Spectroscopy as a Diagnostic in Energetic Materials Testing

Cited by 46 publications

References 59 publications

Impact of oxygen chemistry on the emission and fluorescence spectroscopy of laser ablation plumes

Impact of oxygen chemistry on the emission and fluorescence spectroscopy of laser ablation plumes

Combustion of Mechanically Alloyed Al∙Mg Powders in Products of a Hydrocarbon Flame

Emission and laser absorption spectroscopy of flat flames in aluminum suspensions

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