Combustion of Metals in Oxygen

Grosse, A. V.; Conway, J.B.

doi:10.1021/ie50580a040

Cited by 126 publications

(20 citation statements)

References 7 publications

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“…Consequently, the adiabatic flame temperature of aluminum particles in pure oxygen cannot exceed the boiling temperature of the oxide. The possibility of gas-phase combustion exists because the boiling temperature of aluminum is lower than that of the oxide [79,80]. Table 2 shows the adiabatic flame temperatures and reaction products for aluminum particles in different oxidizers at the pressure p = 1 atm.…”

Section: Gas-phase Versus Surface Combustionmentioning

confidence: 99%

Combustion of nano aluminum particles (Review)

Sundaram

Yang

Зарко

2015

Combust Explos Shock Waves

278

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Nano aluminum particles have received considerable attention in the combustion community; their physicochemical properties are quite favorable as compared with those of their micron-sized counterparts. The present work provides a comprehensive review of recent advances in the field of combustion of nano aluminum particles. The effect of the Knudsen number on heat and mass transfer properties of particles is first examined. Deficiencies of the currently available continuum models for combustion of nano aluminum particles are highlighted. Key physicochemical processes of particle combustion are identified and their respective time scales are compared to determine the combustion mechanisms for different particle sizes and pressures. Experimental data from several sources are gathered to elucidate the effect of the particle size on the flame temperature of aluminum particles. The flame structure and the combustion modes of aluminum particles are examined for wide ranges of pressures, particle sizes, and oxidizers. Key mechanisms that dictate the combustion behaviors are discussed. Measured burning times of nano aluminum particles are surveyed. The effects of the pressure, temperature, particle size, and type and concentration of the oxidizer on the burning time are discussed. A new correlation for the burning time of nano aluminum particles is established. Major outstanding issues to be addressed in the future work are identified.

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Section: Gas-phase Versus Surface Combustionmentioning

confidence: 99%

Combustion of nano aluminum particles (Review)

Sundaram

Yang

Зарко

2015

Combust Explos Shock Waves

278

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“…Other ignition temperature data are given in table 6-A (Ref. 30,34), in which the relative ignitabilities of metal dust clouds in air and metal slabs or sheets in oxygen are compared. Although both sets of data were not obtained under ideal conditions or in the same oxidant atmosphere, they indicate the greater hazard associated with finely dispersed combustibles.…”

Section: B Flammable Solidsmentioning

confidence: 99%

“…C -An RT (34) where C is the mean heat capacity, An is the change in gaseous reactant and product moles, R is the gas constant, and T is the mixture temperature; C = C -R. The temperature rises are greater by several hundred degrees V for Bonstant volume than for constant pressure combustion. In the above case, the maximum flame temperature for constant volume burning of the methane limit mixture is approximately 3300°R (2840°F).…”

Section: Fire and Explosion Damage A Fire Temperatures -Gaseous Fuelsmentioning

confidence: 99%

Fire and Explosion Manual for Aircraft Accident Investigators

Kuchta¹

1973

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“…Moreover, augmented radiation heat transfer reduces the r f (G) dependence, enabling solid fuel ballistic response tailoring [20]. Aluminum is an attractive candidate as an energetic filler, thanks to its oxidation enthalpy [21] and its commercial availability at different dispersity levels (from micron-sized particles to the nanoscale), enabling its use as it is, or as an ingredient for composite additives [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…The presence of metal additives, including Al, implies the possible insurgence of performance losses due to incomplete metal combustion, two-phase flow expansion, and residual accumulation Aerospace 2019, 6, 127 3 of 33 in the combustion chamber/nozzle walls [17][18][19][20][21][22]. All these issues are of particular relevance in HRE combustion due to the diffusion-limited mechanism and the relatively low combustion efficiency of these systems.…”

Section: Introductionmentioning

confidence: 99%

Nano-Sized and Mechanically Activated Composites: Perspectives for Enhanced Mass Burning Rate in Aluminized Solid Fuels for Hybrid Rocket Propulsion

Paravan

2019

Aerospace

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This work provides a lab-scale investigation of the ballistics of solid fuel formulations based on hydroxyl-terminated polybutadiene and loaded with Al-based energetic additives. Tested metal-based fillers span from micron- to nano-sized powders and include oxidizer-containing fuel-rich composites. The latter are obtained by chemical and mechanical processes providing reduced diffusion distance between Al and the oxidizing species source. A thorough pre-burning characterization of the additives is performed. The combustion behaviors of the tested formulations are analyzed considering the solid fuel regression rate and the mass burning rate as the main parameters of interest. A non-metallized formulation is taken as baseline for the relative grading of the tested fuels. Instantaneous and time-average regression rate data are determined by an optical time-resolved technique. The ballistic responses of the fuels are analyzed together with high-speed visualizations of the regressing surface. The fuel formulation loaded with 10 wt.% nano-sized aluminum (ALEX-100) shows a mass burning rate enhancement over the baseline of 55% ± 11% for an oxygen mass flux of 325 ± 20 kg/(m2∙s), but this performance increase nearly disappears as combustion proceeds. Captured high-speed images of the regressing surface show the critical issue of aggregation affecting the ALEX-100-loaded formulation and hindering the metal combustion. The oxidizer-containing composite additives promote metal ignition and (partial) burning in the oxidizer-lean region of the reacting boundary layer. Fuels loaded with 10 wt.% fluoropolymer-coated nano-Al show mass burning rate enhancement over the baseline >40% for oxygen mass flux in the range 325 to 155 kg/(m2∙s). The regression rate data of the fuel composition loaded with nano-sized Al-ammonium perchlorate composite show similar results. In these formulations, the oxidizer content in the fuel grain is <2 wt.%, but it plays a key role in performance enhancement thanks to the reduced metal–oxidizer diffusion distance. Formulations loaded with mechanically activated ALEX-100–polytetrafluoroethylene composites show mass burning rate increases up to 140% ± 20% with metal mass fractions of 30%. This performance is achieved with the fluoropolymer mass fraction in the additive of 45%.

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Combustion of Metals in Oxygen

Cited by 126 publications

References 7 publications

Combustion of nano aluminum particles (Review)

Combustion of nano aluminum particles (Review)

Fire and Explosion Manual for Aircraft Accident Investigators

Nano-Sized and Mechanically Activated Composites: Perspectives for Enhanced Mass Burning Rate in Aluminized Solid Fuels for Hybrid Rocket Propulsion

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