Investigation of the Light Emitters in the Aluminum - Water Reaction

Jones, Matthew R.

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https://hdl.handle.net/2142/121769 Copy

Description

Title

Investigation of the Light Emitters in the Aluminum - Water Reaction

Author(s)

Jones, Matthew R.

Issue Date

1990-08

Director of Research (if dissertation) or Advisor (if thesis)

Brewster, Quinn

Department of Study

Mechanical Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S. (master's)

Degree Level

Thesis

Keyword(s)

• Aluminum
• Water reaction

Language

eng

Abstract

The exploding wire technique was used in connection with spectroscopic measurements and high speed photography to investigate the nature of the radiant emission from the Al - H2O combustion process. Small aluminum wires were successfully ignited under water at various pressures, but a complete, self sustained reaction of the aluminum was not achieved. The spectra measured in this study are qualitatively the same at the different pressures, but the intensity increases with pressure. Principle features of spectroscopic measurements are two strong lines due to Al, band emission due to AlO and a continuum which is probably due to emission from Al2O3 smoke particles. Other species identified in these spectra are OH, AlH, and H. If the cloud of A}iO3 smoke particles produced by the reaction is modeled as a emitting, absorbing, non-scattering slab of small (Rayleigh) particles, the calculated spectral intensity emitted by the smoke cloud compares well with the measured spectral intensity at longer wavelengths. Since the results of this model depend heavily on the assumption that the smoke particles are not larger than 0.0lμm, this model does not show conclusively that Al2O3 is the continuum emitter. However, it does show that it is possible for Al2O3 to be the source of the observed continuum at the longer wavelengths. Determination of the relative importance of the radiative heat transfer was a primary objective of this study. An estimate of the radiative heat loss at atmospheric pressure was obtained by numerically integrating the spectral intensity over wavelength from 300 nm to 800 nm. Comparison of the energy lost through radiation with a rough estimate of the convective heat loss shows the radiative heat loss plays a significant role in the Al - H2O reaction.

Type of Resource

text

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