Influence of rapid laser heating on differently matured soot with double-pulse laser-induced incandescence
Török, Sandra LU ; Mannazhi, Manu LU ; Bergqvist, Saga LU ; Le, Kim Cuong LU
and Bengtsson, Per Erik
LU
(2022)
In Aerosol Science and Technology
56(6).
p.488-501
- Abstract
For accurate laser-induced incandescence (LII) measurements of soot properties it is of great importance to understand the nature of the physical processes involved during rapid laser heating. In this work, we investigate how well-characterized differently matured fresh soot from a soot generator responds to rapid laser heating. For this purpose, a double-pulse LII setup is used with 10 μs time separation between the pulses using various combinations of two common LII wavelengths (532 and 1064 nm). Detection is performed at two wavelength bands for fluorescence analysis, and additionally elastic light scattering is used for mass loss analysis during heating. We investigate how the LII signal changes with pre-heating laser energy,... (More)
For accurate laser-induced incandescence (LII) measurements of soot properties it is of great importance to understand the nature of the physical processes involved during rapid laser heating. In this work, we investigate how well-characterized differently matured fresh soot from a soot generator responds to rapid laser heating. For this purpose, a double-pulse LII setup is used with 10 μs time separation between the pulses using various combinations of two common LII wavelengths (532 and 1064 nm). Detection is performed at two wavelength bands for fluorescence analysis, and additionally elastic light scattering is used for mass loss analysis during heating. We investigate how the LII signal changes with pre-heating laser energy, specifically by fluence curve analysis to estimate the influence of thermal annealing, sublimation and laser-induced fluorescence interference. It is shown that extensive absorption enhancement occurs for all types of soot as the soot is thermally annealed, which is manifested through decreasing dispersion coefficient ξ and an increasing absorption coefficient E(m,λ). When comparing young and mature soot, a much larger impact of sublimation can be observed in the fluence curves of the mature soot. Also, we observe an enhanced contribution of laser-induced fluorescence for the young soot when performing LII measurements using 532 nm, which is suggested to originate from vaporized carbon fragments with an aromatic structure. This work further shows the potential of utilizing double-pulse arrangements for increasing the detectability of poorly absorbing soot, but also it highlights the impact of laser heating on soot, which may be important to avoid interferences when performing soot diagnostics.
(Less)
- author
- Török, Sandra
LU
; Mannazhi, Manu
LU
; Bergqvist, Saga
LU
; Le, Kim Cuong
LU
and Bengtsson, Per Erik
LU
- organization
- publishing date
- 2022
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Kihong Park
- in
- Aerosol Science and Technology
- volume
- 56
- issue
- 6
- pages
- 14 pages
- publisher
- Taylor & Francis
- external identifiers
-
- scopus:85128868655
- ISSN
- 0278-6826
- DOI
- 10.1080/02786826.2022.2046689
- language
- English
- LU publication?
- yes
- id
- 7fe60fa8-e532-476d-b198-979f27a584c1
- date added to LUP
- 2022-07-01 12:11:44
- date last changed
- 2023-05-16 13:09:53
@article{7fe60fa8-e532-476d-b198-979f27a584c1,
abstract = {{<p>For accurate laser-induced incandescence (LII) measurements of soot properties it is of great importance to understand the nature of the physical processes involved during rapid laser heating. In this work, we investigate how well-characterized differently matured fresh soot from a soot generator responds to rapid laser heating. For this purpose, a double-pulse LII setup is used with 10 μs time separation between the pulses using various combinations of two common LII wavelengths (532 and 1064 nm). Detection is performed at two wavelength bands for fluorescence analysis, and additionally elastic light scattering is used for mass loss analysis during heating. We investigate how the LII signal changes with pre-heating laser energy, specifically by fluence curve analysis to estimate the influence of thermal annealing, sublimation and laser-induced fluorescence interference. It is shown that extensive absorption enhancement occurs for all types of soot as the soot is thermally annealed, which is manifested through decreasing dispersion coefficient ξ and an increasing absorption coefficient E(m,λ). When comparing young and mature soot, a much larger impact of sublimation can be observed in the fluence curves of the mature soot. Also, we observe an enhanced contribution of laser-induced fluorescence for the young soot when performing LII measurements using 532 nm, which is suggested to originate from vaporized carbon fragments with an aromatic structure. This work further shows the potential of utilizing double-pulse arrangements for increasing the detectability of poorly absorbing soot, but also it highlights the impact of laser heating on soot, which may be important to avoid interferences when performing soot diagnostics.</p>}},
author = {{Török, Sandra and Mannazhi, Manu and Bergqvist, Saga and Le, Kim Cuong and Bengtsson, Per Erik}},
issn = {{0278-6826}},
keywords = {{Kihong Park}},
language = {{eng}},
number = {{6}},
pages = {{488--501}},
publisher = {{Taylor & Francis}},
series = {{Aerosol Science and Technology}},
title = {{Influence of rapid laser heating on differently matured soot with double-pulse laser-induced incandescence}},
url = {{http://dx.doi.org/10.1080/02786826.2022.2046689}},
doi = {{10.1080/02786826.2022.2046689}},
volume = {{56}},
year = {{2022}},
}