Comparison of the Lift-Off Lengths Obtained by Simultaneous OH-LIF and OH∗ Chemiluminescence Imaging in an Optical Heavy-Duty Diesel Engine
(2015) 12th International Conference on Engines and Vehicles, ICE 2015 2015-September.- Abstract
The presence of OH radicals as a marker of the high temperature reaction region usually has been used to determine the lift-off length (LOL) in diesel engines. Both OH Laser Induced Fluorescence (LIF) and OH∗ chemiluminescence diagnostics have been widely used in optical engines for measuring the LOL. OH∗ chemiluminescence is radiation from OH being formed in the exited states (OH∗). As a consequence OH∗ chemiluminescence imaging provides line-of-sight information across the imaged volume. In contrast, OH-LIF provides information on the distribution of radicals present in the energy ground state. The OH-LIF images only show OH distribution in the thin cross-section illuminated by the laser. When both these techniques have been applied... (More)
The presence of OH radicals as a marker of the high temperature reaction region usually has been used to determine the lift-off length (LOL) in diesel engines. Both OH Laser Induced Fluorescence (LIF) and OH∗ chemiluminescence diagnostics have been widely used in optical engines for measuring the LOL. OH∗ chemiluminescence is radiation from OH being formed in the exited states (OH∗). As a consequence OH∗ chemiluminescence imaging provides line-of-sight information across the imaged volume. In contrast, OH-LIF provides information on the distribution of radicals present in the energy ground state. The OH-LIF images only show OH distribution in the thin cross-section illuminated by the laser. When both these techniques have been applied in earlier work, it has often been reported that the chemiluminescence measurements result in shorter lift-off lengths than the LIF approach. In order to investigate this discrepancy this work presents a dedicated comparison of the LOL obtained from these two diagnostic techniques. In diesel engines, the cycle-to-cycle variations in lift-off region are usually significant. To avoid misinterpretations caused by these variations simultaneous measurements are needed. The statistical analysis based on our simultaneous data can conclude that the OH-LIF method yields longer LOL than the OH∗ chemiluminescence method by a smaller sample size and more precisely than non-simultaneous data. This can be partially explained by the 3D geometry and flame axis asymmetry effects. A numerical simulation with OH and OH∗ distribution was performed for the comparison. It shows a great agreement with the experimental results in this study.
(Less)
- author
- Li, Zheming LU ; Yu, Xin ; Lequien, Guillaume LU ; Lind, Ted LU ; Jansons, Marcis ; Andersson, Öivind LU and Richter, Mattias LU
- organization
- publishing date
- 2015-09-06
- type
- Chapter in Book/Report/Conference proceeding
- publication status
- published
- subject
- host publication
- 12th International Conference on Engines and Vehicles, ICE 2015
- volume
- 2015-September
- edition
- September
- publisher
- Society of Automotive Engineers
- conference name
- 12th International Conference on Engines and Vehicles, ICE 2015
- conference location
- Capri, Naples, Italy
- conference dates
- 2015-09-13 - 2015-09-15
- external identifiers
-
- scopus:84959374568
- DOI
- 10.4271/2015-24-2418
- language
- English
- LU publication?
- yes
- id
- 8431f352-0c98-4b0a-ba12-0b936c54ef4c
- date added to LUP
- 2016-09-23 09:01:58
- date last changed
- 2022-01-30 06:18:55
@inproceedings{8431f352-0c98-4b0a-ba12-0b936c54ef4c,
abstract = {{<p>The presence of OH radicals as a marker of the high temperature reaction region usually has been used to determine the lift-off length (LOL) in diesel engines. Both OH Laser Induced Fluorescence (LIF) and OH∗ chemiluminescence diagnostics have been widely used in optical engines for measuring the LOL. OH∗ chemiluminescence is radiation from OH being formed in the exited states (OH∗). As a consequence OH∗ chemiluminescence imaging provides line-of-sight information across the imaged volume. In contrast, OH-LIF provides information on the distribution of radicals present in the energy ground state. The OH-LIF images only show OH distribution in the thin cross-section illuminated by the laser. When both these techniques have been applied in earlier work, it has often been reported that the chemiluminescence measurements result in shorter lift-off lengths than the LIF approach. In order to investigate this discrepancy this work presents a dedicated comparison of the LOL obtained from these two diagnostic techniques. In diesel engines, the cycle-to-cycle variations in lift-off region are usually significant. To avoid misinterpretations caused by these variations simultaneous measurements are needed. The statistical analysis based on our simultaneous data can conclude that the OH-LIF method yields longer LOL than the OH∗ chemiluminescence method by a smaller sample size and more precisely than non-simultaneous data. This can be partially explained by the 3D geometry and flame axis asymmetry effects. A numerical simulation with OH and OH∗ distribution was performed for the comparison. It shows a great agreement with the experimental results in this study.</p>}},
author = {{Li, Zheming and Yu, Xin and Lequien, Guillaume and Lind, Ted and Jansons, Marcis and Andersson, Öivind and Richter, Mattias}},
booktitle = {{12th International Conference on Engines and Vehicles, ICE 2015}},
language = {{eng}},
month = {{09}},
publisher = {{Society of Automotive Engineers}},
title = {{Comparison of the Lift-Off Lengths Obtained by Simultaneous OH-LIF and OH∗ Chemiluminescence Imaging in an Optical Heavy-Duty Diesel Engine}},
url = {{http://dx.doi.org/10.4271/2015-24-2418}},
doi = {{10.4271/2015-24-2418}},
volume = {{2015-September}},
year = {{2015}},
}