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3868882 
Journal Article 
Study of aluminum particle combustion in solid propellant plumes using digital in-line holography and imaging pyrometry 
Chen, Yi; Guildenbecher, DR; Hoffmeister, KNG; Cooper, MA; Stauffacher, HL; Oliver, MS; Washburn, EB 
2017 
Yes 
Combustion and Flame
ISSN: 0010-2180 
182 
225-237 
English 
WOS:000404945100021 
The combustion of molten metals is an important area of study with applications ranging from solid aluminized rocket propellants to fireworks displays. This work uses digital in-line holography (DIH) to experimentally quantify the three-dimensional position, size, and velocity of aluminum particles during combustion of ammonium perchlorate (AP) based solid-rocket propellants. In addition, spatially resolved particle temperatures are simultaneously measured using two-color imaging pyrometry. To allow for fast characterization of the properties of tens of thousands of particles, automated data processing routines are proposed. Using these methods, statistics from aluminum particles with diameters ranging from 15 to 900 mu m are collected at an ambient pressure of 83 kPa. In the first set of DIH experiments, increasing initial propellant temperature is shown to enhance the agglomeration of nascent aluminum at the burning surface, resulting in ejection of large molten aluminum particles into the exhaust plume. The resulting particle number and volume distributions are quantified. In the second set of simultaneous DIH and pyrometry experiments, particle size and velocity relationships as well as temperature statistics are explored. The average measured temperatures are found to be 2640 +/- 282 K, which compares well with previous estimates of the range of particle and gas-phase temperatures. The novel methods proposed here represent new capabilities for simultaneous quantification of the joint size, velocity, and temperature statistics during the combustion of molten metal particles. The proposed techniques are expected to be useful for detailed performance assessment of metalized solid-rocket propellants. (C) 2017 The Combustion Institute. Published by Elsevier Inc. All rights reserved. 
Aluminum particle combustion; Ammonium perchlorate; Metalized solid propellant; Digital in-line holography; Imaging pyrometer