1 option
Comparison of the Lift-Off Lengths Obtained by Simultaneous OH-LIF and OH* Chemiluminescence Imaging in an Optical Heavy-Duty Diesel Engine Lund Univ
- Format:
- Conference/Event
- Author/Creator:
- Li, Li, author.
- Conference Name:
- 12th International Conference on Engines & Vehicles (2015-09-13 : Capri, Italy)
- Language:
- English
- Physical Description:
- 1 online resource
- Place of Publication:
- Warrendale, PA SAE International 2015
- Summary:
- AbstractThe 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
- Notes:
- Vendor supplied data
- Publisher Number:
- 2015-24-2418
- Access Restriction:
- Restricted for use by site license
The Penn Libraries is committed to describing library materials using current, accurate, and responsible language. If you discover outdated or inaccurate language, please fill out this feedback form to report it and suggest alternative language.