Quantitative measurement of aluminum atom number density around a burning micron-sized aluminum droplet using spatially resolved laser absorption spectroscopy
Ruan, Can LU ; Wu, Zhiyong LU
; Qiu, Yue
LU
; Berrocal, Edouard
LU
; Aldén, Marcus
LU
; Bai, Xue Song
LU
and Li, Zhongshan
LU
(2025)
In Combustion and Flame
279.
- Abstract
In this study, we demonstrate a successful application of laser absorption spectroscopy in an in-situ optical diagnostic system to map the radial distribution of the number density of vapor-phase aluminum (Al) atoms around a burning micron-sized Al droplet. This technique overcomes the challenges associated with the short optical path (at micron scale) and offers high sensitivity to Al atom concentration variations. Results indicate that the number density of Al atoms decreases sharply from ∼1.1 × 1022/m3 within r/r0 = 1.2∼1.4 (r0 is the radius of the Al droplet and r is the distance from the center of the droplet) to ∼4.0 × 1021/m3 within r/r0 = 1.4∼1.6, prior... (More)
In this study, we demonstrate a successful application of laser absorption spectroscopy in an in-situ optical diagnostic system to map the radial distribution of the number density of vapor-phase aluminum (Al) atoms around a burning micron-sized Al droplet. This technique overcomes the challenges associated with the short optical path (at micron scale) and offers high sensitivity to Al atom concentration variations. Results indicate that the number density of Al atoms decreases sharply from ∼1.1 × 1022/m3 within r/r0 = 1.2∼1.4 (r0 is the radius of the Al droplet and r is the distance from the center of the droplet) to ∼4.0 × 1021/m3 within r/r0 = 1.4∼1.6, prior to the formation of the Al2O3 condensation layer (r/r0 = 1.6∼1.9). This largest decline rate in the radial direction indicates the ‘flame front’ location. Additionally, a substantial number of Al atoms, i.e., at the scale of 1019∼1021/m3, are still present beyond the Al2O3 condensation layer, and their number densities continue to decrease further outwards gradually. This result agrees with the trend predicted by our detailed numerical simulation. Moreover, it is shown that the produced Al2O3 droplets are stable, as no detectable absorption signals from Al atoms can be found from the Al2O3 droplet dissociation even at ∼3500 K. In addition, as we used the radial temperature profiles obtained from simulations to correlate the number densities of Al atoms in different ground states, an uncertainty analysis was performed. It was shown that this might introduce a maximum uncertainty of 1.84 % in the total Al atom number density. To the awareness of the authors, this work represents the first quantitative in-situ measurement of the Al atom number density around a burning micron-sized Al droplet.
(Less)
- author
- Ruan, Can
LU
; Wu, Zhiyong
LU
; Qiu, Yue
LU
; Berrocal, Edouard
LU
; Aldén, Marcus
LU
; Bai, Xue Song
LU
and Li, Zhongshan
LU
- organization
- publishing date
- 2025-09
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Al atom distribution, Aluminum combustion, Carbon-free energy, Laser absorption spectroscopy, Metal combustion
- in
- Combustion and Flame
- volume
- 279
- article number
- 114297
- publisher
- Elsevier
- external identifiers
-
- scopus:105008521863
- ISSN
- 0010-2180
- DOI
- 10.1016/j.combustflame.2025.114297
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2025 The Author(s)
- id
- 6e0036a1-92e6-4f0a-b041-5273764872e2
- date added to LUP
- 2025-06-30 13:20:50
- date last changed
- 2025-07-02 03:31:35
@article{6e0036a1-92e6-4f0a-b041-5273764872e2,
abstract = {{<p>In this study, we demonstrate a successful application of laser absorption spectroscopy in an in-situ optical diagnostic system to map the radial distribution of the number density of vapor-phase aluminum (Al) atoms around a burning micron-sized Al droplet. This technique overcomes the challenges associated with the short optical path (at micron scale) and offers high sensitivity to Al atom concentration variations. Results indicate that the number density of Al atoms decreases sharply from ∼1.1 × 10<sup>22</sup>/m<sup>3</sup> within r/r<sub>0</sub> = 1.2∼1.4 (r<sub>0</sub> is the radius of the Al droplet and r is the distance from the center of the droplet) to ∼4.0 × 10<sup>21</sup>/m<sup>3</sup> within r/r<sub>0</sub> = 1.4∼1.6, prior to the formation of the Al<sub>2</sub>O<sub>3</sub> condensation layer (r/r<sub>0</sub> = 1.6∼1.9). This largest decline rate in the radial direction indicates the ‘flame front’ location. Additionally, a substantial number of Al atoms, i.e., at the scale of 10<sup>19</sup>∼10<sup>21</sup>/m<sup>3</sup>, are still present beyond the Al<sub>2</sub>O<sub>3</sub> condensation layer, and their number densities continue to decrease further outwards gradually. This result agrees with the trend predicted by our detailed numerical simulation. Moreover, it is shown that the produced Al<sub>2</sub>O<sub>3</sub> droplets are stable, as no detectable absorption signals from Al atoms can be found from the Al<sub>2</sub>O<sub>3</sub> droplet dissociation even at ∼3500 K. In addition, as we used the radial temperature profiles obtained from simulations to correlate the number densities of Al atoms in different ground states, an uncertainty analysis was performed. It was shown that this might introduce a maximum uncertainty of 1.84 % in the total Al atom number density. To the awareness of the authors, this work represents the first quantitative in-situ measurement of the Al atom number density around a burning micron-sized Al droplet.</p>}},
author = {{Ruan, Can and Wu, Zhiyong and Qiu, Yue and Berrocal, Edouard and Aldén, Marcus and Bai, Xue Song and Li, Zhongshan}},
issn = {{0010-2180}},
keywords = {{Al atom distribution; Aluminum combustion; Carbon-free energy; Laser absorption spectroscopy; Metal combustion}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Combustion and Flame}},
title = {{Quantitative measurement of aluminum atom number density around a burning micron-sized aluminum droplet using spatially resolved laser absorption spectroscopy}},
url = {{http://dx.doi.org/10.1016/j.combustflame.2025.114297}},
doi = {{10.1016/j.combustflame.2025.114297}},
volume = {{279}},
year = {{2025}},
}