TY - JOUR
T1 - Ignition and combustion of aluminum particles in shocked H2O/O2/Ar and CO2/O2/Ar mixtures
AU - Servaites, James
AU - Krier, Herman
AU - Melcher, J. C.
AU - Burton, R. L.
N1 - Funding Information:
This work is funded by the Ballistic Missile Defense Organization through the Office of Naval Research contract N00014-95-1-1339, and is part of the University of Illinois at Urbana-Champaign Multi-disciplinary University Research Initiative (MURI) center for the study of Novel Energetic Materials. SEM images were made with the assistance of Vania Petrova in the Center for Microanalysis of Materials, UIUC, which is supported by the U.S. Department of Energy under grant DEFG02 to 96-ER45439. Prof. N. Glumac, Department of Mechanical and Industrial Engineering, UIUC, was very helpful in the interpretation of our oxide atomic spectra; his previous work ([18]) was also utilized. Prof. A. Scheeline of UIUC provided spectroscopic advice and insight. Prof. K. S. Suslick of UIUC and Prof. A. Fontijn of Rensselaer Polytechnic Institute provided insight into the chemistry involved in aluminum reactions. We would like to acknowledge assistance in operating the shock tube by undergraduate research assistants Hadas Ritz, Carolina Lopez, and Evgeniy Sklyanskiy.
PY - 2001
Y1 - 2001
N2 - Small aluminum particles (5-10 μm) are ignited in atmospheres consisting of Ar and varying amounts of H2O, CO2, and O2 at the endwall of a shock tube to study the burning characteristics in various combinations of these oxidizers. A reflected shock is used to obtain pressures of ∼8.5 atm and temperatures of ∼2600 K. Visible wavelength emission spectra are recorded by using a spectrometer coupled to a streak camera, and two photodetectors record intensity vs. time at AlO emission wavelengths of 486 and 514 nm. The streak camera allows recording of multiple time-resolved spectra at rates of 100 μs per spectrum. Aluminum particles ignited in mixtures of CO2/O2/Ar exhibited a burn time of about one half that of an atmosphere containing only a mixture of O2/Ar, holding the argon constant at 40%. In addition, as CO2 was substituted for O2 in successive experiments, a nonlinear relationship, as a function of the gas composition, was observed for ignition delay time and burn time. Within mixtures of H2O/O2/Ar, two distinct burning stages are visible for the combusting aluminum particles. As an increasing amount of H2O was substituted for O2 in separate tests, a second distinct burning stage developed. Spectroscopic data recorded during such experiments portray AlO emission during both combustion stages. Aluminum particles combusted in a mixture of H2O/Ar show burn times 2 to 5 times greater than those from CO2/O2/Ar mixtures, and ignition delay times 3 to 6 times greater.
AB - Small aluminum particles (5-10 μm) are ignited in atmospheres consisting of Ar and varying amounts of H2O, CO2, and O2 at the endwall of a shock tube to study the burning characteristics in various combinations of these oxidizers. A reflected shock is used to obtain pressures of ∼8.5 atm and temperatures of ∼2600 K. Visible wavelength emission spectra are recorded by using a spectrometer coupled to a streak camera, and two photodetectors record intensity vs. time at AlO emission wavelengths of 486 and 514 nm. The streak camera allows recording of multiple time-resolved spectra at rates of 100 μs per spectrum. Aluminum particles ignited in mixtures of CO2/O2/Ar exhibited a burn time of about one half that of an atmosphere containing only a mixture of O2/Ar, holding the argon constant at 40%. In addition, as CO2 was substituted for O2 in successive experiments, a nonlinear relationship, as a function of the gas composition, was observed for ignition delay time and burn time. Within mixtures of H2O/O2/Ar, two distinct burning stages are visible for the combusting aluminum particles. As an increasing amount of H2O was substituted for O2 in separate tests, a second distinct burning stage developed. Spectroscopic data recorded during such experiments portray AlO emission during both combustion stages. Aluminum particles combusted in a mixture of H2O/Ar show burn times 2 to 5 times greater than those from CO2/O2/Ar mixtures, and ignition delay times 3 to 6 times greater.
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U2 - 10.1016/S0010-2180(01)00225-5
DO - 10.1016/S0010-2180(01)00225-5
M3 - Article
AN - SCOPUS:0035033067
SN - 0010-2180
VL - 125
SP - 1040
EP - 1054
JO - Combustion and Flame
JF - Combustion and Flame
IS - 1-2
ER -