Combustion of mechanically alloyed Al·Mg powders in products of a hydrocarbon flame

Document Type

Article

Publication Date

5-4-2015

Abstract

Burn times and temperatures were measured optically for a set of mechanically alloyed Al·Mg powders injected into a laminar and a turbulent air-acetylene flame. Magnesium concentrations varied from 10 to 53 mole%; particle sizes were in the range of 1-50 m. Emission from the burning particles at 700 nm, 800 nm, and 900 nm was captured using three filtered photomultiplier tubes. The burn times were correlated with particle sizes using measured statistical distributions for both times and sizes. The measured trends for burn times, t, as a function of particle size, d, for all alloys were approximated by a t = a·dn law, where the exponent n varied from 0.6 to 1. Shorter burn times were measured in more turbulent flows; respectively, the values of pre-exponent, a, decreased and exponent, n, increased slightly with an increased level of turbulence. An increase in Mg concentration led to longer burn times for the alloy particles for all flame conditions. For all compositions, alloy particles burned longer than similarly sized Al particles except for the alloy with the smallest concentration of Mg, Al0.9Mg0.1, for which particles less than 4 m burned faster than similarly sized Al. This effect was observed for laminar and turbulent flames. The optically measured temperatures were lower for Al0.47Mg0.53 alloy (2400 K) compared to 2700-2800 K obtained for other alloys. Turbulent mixing resulted in a slight increase in the measured temperature.

Identifier

84927597382 (Scopus)

Publication Title

Combustion Science and Technology

External Full Text Location

https://doi.org/10.1080/00102202.2014.973951

e-ISSN

1563521X

ISSN

00102202

First Page

807

Last Page

825

Issue

5

Volume

187

Fund Ref

Defense Threat Reduction Agency

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