The effect of stoichiometry on the combustion behavior of a nanoscale Al/M0O3 thermite

G. M. Dutro, Richard A. Yetter, Grant Alexander Risha, S. F. Son

Research output: Contribution to journalConference article

68 Citations (Scopus)

Abstract

The effect of stoichiometry on the combustion behavior of the nanoscale aluminum molybdenum trioxide (nAl/MoO3) thermite was studied in a burn tube experiment by characterizing the propagation velocity and pressure output of the reaction, Changing the stoichiometry affects the combustion through changes in the product temperature, phase, and composition. The mixture ratios of the composites were varied over an extremely wide range (5% nAl (95% MoO3)-90% nAl (10% MoO3)). Results revealed, three separate combustion regimes: a steady high speed propagation (∼100 to ∼1000m/s) from approximately 10% to 65% nAl, an oscillating and accelerating wave near 70% nAl, and a steady-slow speed propagation (∼0.1-1 m/s) from approximately 75% to 85% nAl. Propagation was observed to fail both <10% nAl and >85%) nAl. This is the first known observation of such limits for a nanoscale thermite in a tube geometry. The instrumented tube tests revealed peak pressures over 8 MPa near stoichiometric conditions in the steady high speed propagation region, no measurable pressure rise at low speed propagation, and building pressures for accelerating waves. The results suggest the propagation mode to be a supersonic convective wave for near stoichiometric mixtures and a conductive deflagration for extremely fuel-rich mixtures. The implications of these results for microscale combustion applications are discussed.

Original languageEnglish (US)
Pages (from-to)1921-1928
Number of pages8
JournalProceedings of the Combustion Institute
Volume32 II
Issue number2
DOIs
StatePublished - Jan 1 2009
Event32nd International Symposium on Combustion - Montreal, QC, Canada
Duration: Aug 3 2008Aug 8 2008

Fingerprint

thermites
Stoichiometry
stoichiometry
propagation
tubes
high speed
deflagration
Aluminum
propagation modes
Wave propagation
Molybdenum
propagation velocity
microbalances
low speed
molybdenum
Geometry
molybdenum trioxide
Composite materials
aluminum
Chemical analysis

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

Cite this

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title = "The effect of stoichiometry on the combustion behavior of a nanoscale Al/M0O3 thermite",
abstract = "The effect of stoichiometry on the combustion behavior of the nanoscale aluminum molybdenum trioxide (nAl/MoO3) thermite was studied in a burn tube experiment by characterizing the propagation velocity and pressure output of the reaction, Changing the stoichiometry affects the combustion through changes in the product temperature, phase, and composition. The mixture ratios of the composites were varied over an extremely wide range (5{\%} nAl (95{\%} MoO3)-90{\%} nAl (10{\%} MoO3)). Results revealed, three separate combustion regimes: a steady high speed propagation (∼100 to ∼1000m/s) from approximately 10{\%} to 65{\%} nAl, an oscillating and accelerating wave near 70{\%} nAl, and a steady-slow speed propagation (∼0.1-1 m/s) from approximately 75{\%} to 85{\%} nAl. Propagation was observed to fail both <10{\%} nAl and >85{\%}) nAl. This is the first known observation of such limits for a nanoscale thermite in a tube geometry. The instrumented tube tests revealed peak pressures over 8 MPa near stoichiometric conditions in the steady high speed propagation region, no measurable pressure rise at low speed propagation, and building pressures for accelerating waves. The results suggest the propagation mode to be a supersonic convective wave for near stoichiometric mixtures and a conductive deflagration for extremely fuel-rich mixtures. The implications of these results for microscale combustion applications are discussed.",
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The effect of stoichiometry on the combustion behavior of a nanoscale Al/M0O3 thermite. / Dutro, G. M.; Yetter, Richard A.; Risha, Grant Alexander; Son, S. F.

In: Proceedings of the Combustion Institute, Vol. 32 II, No. 2, 01.01.2009, p. 1921-1928.

Research output: Contribution to journalConference article

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T1 - The effect of stoichiometry on the combustion behavior of a nanoscale Al/M0O3 thermite

AU - Dutro, G. M.

AU - Yetter, Richard A.

AU - Risha, Grant Alexander

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AB - The effect of stoichiometry on the combustion behavior of the nanoscale aluminum molybdenum trioxide (nAl/MoO3) thermite was studied in a burn tube experiment by characterizing the propagation velocity and pressure output of the reaction, Changing the stoichiometry affects the combustion through changes in the product temperature, phase, and composition. The mixture ratios of the composites were varied over an extremely wide range (5% nAl (95% MoO3)-90% nAl (10% MoO3)). Results revealed, three separate combustion regimes: a steady high speed propagation (∼100 to ∼1000m/s) from approximately 10% to 65% nAl, an oscillating and accelerating wave near 70% nAl, and a steady-slow speed propagation (∼0.1-1 m/s) from approximately 75% to 85% nAl. Propagation was observed to fail both <10% nAl and >85%) nAl. This is the first known observation of such limits for a nanoscale thermite in a tube geometry. The instrumented tube tests revealed peak pressures over 8 MPa near stoichiometric conditions in the steady high speed propagation region, no measurable pressure rise at low speed propagation, and building pressures for accelerating waves. The results suggest the propagation mode to be a supersonic convective wave for near stoichiometric mixtures and a conductive deflagration for extremely fuel-rich mixtures. The implications of these results for microscale combustion applications are discussed.

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