Combustion of 5-micron Aluminum Particles in High Temperature, High Pressure, Water-Vapor Environments

Lynch, Patrick T.; Glumac, Nick; Krier, Herman

doi:10.2514/6.2007-5643

Cited by 8 publications

(6 citation statements)

References 5 publications

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“…Models have been expanded to include transport properties and full gas phase chemistry (Beckstead, 2005;Bucher et al, 1998). Washburn et al (2008) modeled Al particles with some agreement with our experimental results Lynch et al, 2007). They included detailed chemistry and mechanisms for the accumulation of condensed-phase products on the surface of the aluminum particle.…”

Section: Introductionmentioning

confidence: 87%

Gas-Phase Reaction in Nanoaluminum Combustion

Lynch

Fiore

Krier

et al. 2010

Combustion Science and Technology

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The presence or absence of gas phase species during combustion of aluminum nanoparticles (n-Al) is a crucial observable in evaluating competing theories such as a diffusive oxidation mechanism and the melt dispersion mechanism. Absorption spectroscopy was used to probe the ground state of aluminum monoxide (AlO) and Al vapor in order to quantify the amount of Al and AlO present under conditions where these species were not observed in emission previously. Absorption measurements were made during combustion of nanoaluminum and micron-sized aluminum in a heterogeneous shock tube. AlO was detected in absorption at temperatures as low as 2000 K in n-Al combustion, slightly below the limit seen in micro-Al combustion. Al vapor was detected during n-Al combustion at temperatures as low as 1500 K, significantly lower than in micro-Al combustion, suggestive of a gas phase component. The detection limit for Al vapor was 1 Â 10 12 cm À3 . The gas phase component was much weaker than that seen in 10 lm Al combustion. A comparison with n-Al in an inert environment did not show Al vapor at temperatures below 2300 K, even though the equilibrium concentration of Al from particles at that temperature were several orders of magnitude higher than the detection limit. This suggests a nearly pristine oxide coat that inhibits the production of Al vapor in appreciable quantities without reaction. These results are contrary to predictions of the melt dispersion mechanism, which should result in the generation of aluminum vapor from high-energy Al clusters produced from n-Al particles that spallate from mechanical stresses under rapid heating. This should further be independent of the bath gas.

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Section: Introductionmentioning

confidence: 87%

Gas-Phase Reaction in Nanoaluminum Combustion

Lynch

Fiore

Krier

et al. 2010

Combustion Science and Technology

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“…The combustion of aluminum particles in air with varying pressure has been already investigated in different studies (Bazyn et al 2006), (Lynch et al 2007), (Marion et al 1996) and (Legrand et al 2001). The theory does not predict the effect of pressure on the combustion time in diffusion regimes but experiments identified a weak effect for low pressure range, influencing melting and vaporization temperatures and potentially combustion dynamics (Legrand et al 2001).…”

Section: Aluminum Combustion Dynamics and Pressure Effectsmentioning

confidence: 99%

“…Since work proposed by Friedman and Maček (1962) using a flame plate burner to ignite aluminum particles and collect quantitative and qualitative information on their combustion, several experimental apparatus have been developed to improve the understanding of the aluminum combustion with increasing accuracy. Shock tubes were often used and permit to analyze the combustion of dust aluminum considering interaction effects between burning particles (Servaites et al 2001) (Bazyn et al 2006) and (Lynch et al 2007). Combustion of single particles was also studied in case of free-falling droplet, aerodynamic levitators or bulk aluminum samples attached to support, considering convective and conductive effects (Wilson and Williams 1971), (Prentice 1974), (Bucher et al 1996), (Sarou-Kanian et al 2003) and (Feng et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Detailed Analysis of Combustion Process of a Single Aluminum Particle in Air Using an Improved Experimental Approach

Braconnier

Chauveau

Halter

et al. 2018

Int J Energetic Materials Chem Prop

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The current experimental study aims at analyzing the self-sustained combustion of 30-120 µm Al particles using an electrostatic levitation system. In this improved setup , a single particle is isolated in air with different ambient pressure (1-31 bar) to be then ignited by a CO2 laser beam. The integrated optical signature of burning Al particle is recorded using filtered photomultipliers and a high-speed camera. The photomultiplier is used to estimate burning time while the camera direct visualization allows to measure the evolution of combustion parameters in real time such as droplet diameter (including initial particle diameter) and flame diameter with important resolution. Important information are also provided to accurately describe combustion phenomenology. Measured burning times according to the pressure are compared to experimental correlations issued from literature and similar trends are observed. The existence of different stages during combustion is clearly evidenced and early assumptions can be made to explain dependence between combustion time and identified phenomena.

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“…Many studies have used time resolved AlO emission to determine the burn time of aluminum particles in a shock tube [13,[22][23][24][25][26][27][28][29], particles flowing in a stream [3,15,30], and aluminum particles in an explosive [16,31,32]. In addition, burn time models were developed using the AlO emission [3,15,24,27,28,30,33]. Some studies have used AlO emission to also study the ignition of aluminum [13,16,17,23,29,30,34].…”

Section: Introductionmentioning

confidence: 99%

On AlO Emission Spectroscopy as a Diagnostic in Energetic Materials Testing

Peuker

Lynch

Krier

et al. 2013

Propellants Explo Pyrotec

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The emission of AlO is commonly observed in tests involving aluminum combustion in propellants and explosives. Such emission has been used as a signature of combustion, as a tool for measuring ignition and reaction times, and as a thermometer. This paper provides a critical review of methodologies exploiting AlO emission spectroscopy as a quantitative tool in energetics testing. Controlled tests involving aluminized explosives, as well as those using added alumina, are conducted, in which AlO emission is quantified and compared to total oxidation in the final residue. Experimental parameters such as optical depth and fireball confinement are systematically varied to examine the effect on AlO emission. We find that thermometry using AlO remains valid, and a new approach to using low resolution spectra is proposed. However, AlO emission spectroscopy or photometry can be quantitatively correlated to ignition and burning time, or used to infer the presence or absence of aluminum combustion, only under a limited set of circumstances. Factors that limit the ability to use AlO emission quantitatively are discussed in depth.

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Combustion of 5-micron Aluminum Particles in High Temperature, High Pressure, Water-Vapor Environments

Cited by 8 publications

References 5 publications

Gas-Phase Reaction in Nanoaluminum Combustion

Gas-Phase Reaction in Nanoaluminum Combustion

Detailed Analysis of Combustion Process of a Single Aluminum Particle in Air Using an Improved Experimental Approach

On AlO Emission Spectroscopy as a Diagnostic in Energetic Materials Testing

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