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Combustion characteristics of well-dispersed boron submicroparticles and plasma effect

Yu, Dan; Kong, Chengdong LU ; Zhuo, Jiankun; Yao, Qiang; Li, Shuiqing; Wang, Mengze and Tian, Zhen Yu (2018) In Combustion and Flame 188. p.94-103
Abstract

Boron is an attractive high-energy fuel additive. But it could not burn efficiently in practical systems due to its high ignition temperature and slow burning velocity. Finding methods to enhance the combustion of boron is desired. This work focused on the combustion characteristics of boron submicroparticles with and without plasma discharges in a hot environment supported by CH4/N2/O2 flat flame based on the optical diagnostics. The boron submicroparticles were dispersed by the nebulization method to control the agglomeration. The well-dispersed boron flame exhibited two different burning modes, depending on the ambient temperature. As the ambient temperature was above 1520 K, the boron flame showed... (More)

Boron is an attractive high-energy fuel additive. But it could not burn efficiently in practical systems due to its high ignition temperature and slow burning velocity. Finding methods to enhance the combustion of boron is desired. This work focused on the combustion characteristics of boron submicroparticles with and without plasma discharges in a hot environment supported by CH4/N2/O2 flat flame based on the optical diagnostics. The boron submicroparticles were dispersed by the nebulization method to control the agglomeration. The well-dispersed boron flame exhibited two different burning modes, depending on the ambient temperature. As the ambient temperature was above 1520 K, the boron flame showed definitely two-stage characteristics where the upstream of particle flow was yellow, corresponding to the first-stage flame, while the downstream was green and diffusive, corresponding to the second-stage flame. The first-stage and second-stage burn times were respectively in the range of 0.46–1.08 ms and 0.92–1.87 ms, as the ambient temperature decreased from 1752 K to 1520 K. The chemical kinetics-controlled mechanism was confirmed by the nearly linear size dependence of the burn time (d1 law). Nevertheless, as the ambient temperature was below 1520 K, the boron submicroparticles were partially burned or oxidized, exhibiting a mildly orange stream. This mild boron flame could be enhanced using a plasma discharge. The ignition delay time was shortened from 3.06 ms to 0.77 ms when the discharge was introduced at the ignition delay stage. The two-stage combustion characteristics occurred when the discharge was introduced at the combustion stage.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Boron particle, Kinetics-controlled, Plasma assistance, Two-stage combustion
in
Combustion and Flame
volume
188
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:85030999955
ISSN
0010-2180
DOI
10.1016/j.combustflame.2017.09.022
language
English
LU publication?
yes
id
c17cc183-ff2e-47b0-a22f-40c3021df3b2
date added to LUP
2017-10-25 14:37:32
date last changed
2018-01-07 12:23:30
@article{c17cc183-ff2e-47b0-a22f-40c3021df3b2,
  abstract     = {<p>Boron is an attractive high-energy fuel additive. But it could not burn efficiently in practical systems due to its high ignition temperature and slow burning velocity. Finding methods to enhance the combustion of boron is desired. This work focused on the combustion characteristics of boron submicroparticles with and without plasma discharges in a hot environment supported by CH<sub>4</sub>/N<sub>2</sub>/O<sub>2</sub> flat flame based on the optical diagnostics. The boron submicroparticles were dispersed by the nebulization method to control the agglomeration. The well-dispersed boron flame exhibited two different burning modes, depending on the ambient temperature. As the ambient temperature was above 1520 K, the boron flame showed definitely two-stage characteristics where the upstream of particle flow was yellow, corresponding to the first-stage flame, while the downstream was green and diffusive, corresponding to the second-stage flame. The first-stage and second-stage burn times were respectively in the range of 0.46–1.08 ms and 0.92–1.87 ms, as the ambient temperature decreased from 1752 K to 1520 K. The chemical kinetics-controlled mechanism was confirmed by the nearly linear size dependence of the burn time (d<sup>1</sup> law). Nevertheless, as the ambient temperature was below 1520 K, the boron submicroparticles were partially burned or oxidized, exhibiting a mildly orange stream. This mild boron flame could be enhanced using a plasma discharge. The ignition delay time was shortened from 3.06 ms to 0.77 ms when the discharge was introduced at the ignition delay stage. The two-stage combustion characteristics occurred when the discharge was introduced at the combustion stage.</p>},
  author       = {Yu, Dan and Kong, Chengdong and Zhuo, Jiankun and Yao, Qiang and Li, Shuiqing and Wang, Mengze and Tian, Zhen Yu},
  issn         = {0010-2180},
  keyword      = {Boron particle,Kinetics-controlled,Plasma assistance,Two-stage combustion},
  language     = {eng},
  pages        = {94--103},
  publisher    = {Elsevier},
  series       = {Combustion and Flame},
  title        = {Combustion characteristics of well-dispersed boron submicroparticles and plasma effect},
  url          = {http://dx.doi.org/10.1016/j.combustflame.2017.09.022},
  volume       = {188},
  year         = {2018},
}