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Development and Application of Laser-Induced Emission Techniques for Combustion Diagnostics -High-Resolution Visualization of Turbulent Reacting Flows

Li, Bo LU (2012)
Abstract (Swedish)
Popular Abstract in Swedish

Sedan människan lyckades skapa eld har förbränning utgjort den viktigaste energikällan i mänsklighetens långa historia, viket den ser ut att fortsätta vara det inom en överskådlig framtid. I dagsläget kommer mer än 90% av vår energi från förbränningsprocesser. Dock uppstår en rad problem kring förbränning, såsom föroreningar och möjligheten till använda sig av förnyelsebara bränslen. Därför är det mycket viktigt med forskning kring förbränning i syfte att minska utsläppen, öka effektiviteten och säkerheten, hitta rena och förnyelsebara bränslen, etc.

Förbränning är ett synnerligen komplicerat fenomen som involverar tusentals reaktioner och intermediära ämnen. Traditionellt han man... (More)
Popular Abstract in Swedish

Sedan människan lyckades skapa eld har förbränning utgjort den viktigaste energikällan i mänsklighetens långa historia, viket den ser ut att fortsätta vara det inom en överskådlig framtid. I dagsläget kommer mer än 90% av vår energi från förbränningsprocesser. Dock uppstår en rad problem kring förbränning, såsom föroreningar och möjligheten till använda sig av förnyelsebara bränslen. Därför är det mycket viktigt med forskning kring förbränning i syfte att minska utsläppen, öka effektiviteten och säkerheten, hitta rena och förnyelsebara bränslen, etc.

Förbränning är ett synnerligen komplicerat fenomen som involverar tusentals reaktioner och intermediära ämnen. Traditionellt han man undersökt förbränning med probtekniker. Sonden som man för in i flamman kommer emellertid att påverka och förändra flamman, vilket gör att information som probmätningen ger är påverkad av själva mätningen. Därför använder vi oss av lasertekniker för att diagnostisera förbränning utan att störa den, och information som förvärvats genom lasermätningar blir således mer tillförlitlig.

Den teknik som jag huvudsakligen har använt mig av i avhandlingen kallas laser-inducerad fluorescens (LIF). Laser används som ljuskälla och strålen dirigeras in i lågan. Om lasern har en speciell färg kan endast ett ämne i lågan påverkas varpå de andra ämnena kan betraktas som genomskinliga. De ämnen som påverkas av laserns ljus sänder i sin tur ut ljus med en annan färg som kallas fluorescens. Genom att avbilda fluorescensen med en kamera får man en bild av fördelningen av detta ämne i flamman. Jag ska ge ett exempel på hur denna teknik används vid förbränningforskning. Förbränningen kan ske i turbulent miljö och turbulensen genererar en hel del mycket små virvlar. Genom att avbilda LIF-signalen med en kamera visualiseras ett visst ämne i virvelstrukturen med hög spatial upplösning. För olika flamförhållanden kommer vi att se olika strukturer, vilket gör att man får värdefull information kring förbränningsprocesser, såsom samspelet mellan turbulens och kemiska reaktioner i förbränning. (Less)
Abstract
Nowadays, more than 90% of our energy comes from combustion processes. Hence, it is very important to perform combustion research to reduce emissions, improve efficiency, find clean and renewable fuels, strengthen safety, etc. The complexity of combustion processes asks for advanced diagnostic tools, among which the laser spectroscopy has been proved to be a powerful one.

This thesis is about the application and development of laser-induced emission techniques for combustion diagnostics. Different laser techniques have been adopted, i.e., laser-induced fluorescence (LIF), laser Rayleigh scattering, and laser-induced phosphorescence (LIP). Brief descriptions of these techniques and the main equipment used are given in the... (More)
Nowadays, more than 90% of our energy comes from combustion processes. Hence, it is very important to perform combustion research to reduce emissions, improve efficiency, find clean and renewable fuels, strengthen safety, etc. The complexity of combustion processes asks for advanced diagnostic tools, among which the laser spectroscopy has been proved to be a powerful one.

This thesis is about the application and development of laser-induced emission techniques for combustion diagnostics. Different laser techniques have been adopted, i.e., laser-induced fluorescence (LIF), laser Rayleigh scattering, and laser-induced phosphorescence (LIP). Brief descriptions of these techniques and the main equipment used are given in the thesis.

The first part of the thesis deals with application of laser techniques in turbulent combustion. The high spatial resolution of planar LIF (PLIF) and Rayleigh thermometry were performed in premixed and partially premixed laboratory flames. Visualization of flame fronts by CH2O, CH, and OH PLIF as well as temperature fields were achieved to study the interaction between turbulence and chemistry. Simulated results were used to explain the combustion phenomena, and the experimental results were analyzed for model validation

The second part focuses on the development of the combustion apparatus and diagnostic techniques. A novel burner, featuring a multi-jet structure, was developed as a temperature calibration source. We can easily achieve a wide range of temperatures from ~1000 K up to ~2000 K in the burned gas region of the burner, which were measured by Rayleigh scattering. Another development is on the Heat Flux burner. By application of LIP technique instead of thermocouples (TC), the temperature distribution along the radius of the burner perforated plate was measured more precisely, which reduces the uncertainty of measured flame burning velocity, e.g., from ±1.5 cm/s (TC-introduced uncertainty) to ±0.25 cm/s (LIP-introduced uncertainty) in a Φ=0.7 methane/air flame. Development was also achieved by extending the technique of photofragmentation LIF (PF-LIF) of H2O2 in an HCCI engine. Quantitative concentration as well as single-shot imaging of H2O2 were acquired. A similar technique like PF-LIF was also carried out for C2H2 measurements under atmospheric pressure. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Dr. Dam, Nico, Combustion Technology, Dept. of Mechanical Engineering, Eindhoven University of Technology, the Netherlands
organization
publishing date
type
Thesis
publication status
published
subject
keywords
PLIF, LIF, Laser-Induced Fluorescence, Rayleigh scattering, Laser Diagnostics, flame font, Combustion, Turbulence, Photofragmentation LIF, PF-LIF, Laser-induced Phosphorescence, LIP, Fysicumarkivet A:2012:Li
pages
95 pages
defense location
Hörsal B, Fysiska institutionen, Sölvegatan 14 C, Lund
defense date
2012-06-12 10:15
ISSN
1102-8718
ISBN
978-91-7473-280-1
language
English
LU publication?
yes
id
c501c014-f780-40a4-baaa-3c1de399bf94 (old id 2539333)
date added to LUP
2012-05-10 09:35:34
date last changed
2016-09-19 08:45:01
@phdthesis{c501c014-f780-40a4-baaa-3c1de399bf94,
  abstract     = {Nowadays, more than 90% of our energy comes from combustion processes. Hence, it is very important to perform combustion research to reduce emissions, improve efficiency, find clean and renewable fuels, strengthen safety, etc. The complexity of combustion processes asks for advanced diagnostic tools, among which the laser spectroscopy has been proved to be a powerful one.<br/><br>
This thesis is about the application and development of laser-induced emission techniques for combustion diagnostics. Different laser techniques have been adopted, i.e., laser-induced fluorescence (LIF), laser Rayleigh scattering, and laser-induced phosphorescence (LIP). Brief descriptions of these techniques and the main equipment used are given in the thesis.<br/><br>
The first part of the thesis deals with application of laser techniques in turbulent combustion. The high spatial resolution of planar LIF (PLIF) and Rayleigh thermometry were performed in premixed and partially premixed laboratory flames. Visualization of flame fronts by CH2O, CH, and OH PLIF as well as temperature fields were achieved to study the interaction between turbulence and chemistry. Simulated results were used to explain the combustion phenomena, and the experimental results were analyzed for model validation<br/><br>
The second part focuses on the development of the combustion apparatus and diagnostic techniques. A novel burner, featuring a multi-jet structure, was developed as a temperature calibration source. We can easily achieve a wide range of temperatures from ~1000 K up to ~2000 K in the burned gas region of the burner, which were measured by Rayleigh scattering. Another development is on the Heat Flux burner. By application of LIP technique instead of thermocouples (TC), the temperature distribution along the radius of the burner perforated plate was measured more precisely, which reduces the uncertainty of measured flame burning velocity, e.g., from ±1.5 cm/s (TC-introduced uncertainty) to ±0.25 cm/s (LIP-introduced uncertainty) in a Φ=0.7 methane/air flame. Development was also achieved by extending the technique of photofragmentation LIF (PF-LIF) of H2O2 in an HCCI engine. Quantitative concentration as well as single-shot imaging of H2O2 were acquired. A similar technique like PF-LIF was also carried out for C2H2 measurements under atmospheric pressure.},
  author       = {Li, Bo},
  isbn         = {978-91-7473-280-1},
  issn         = {1102-8718},
  keyword      = {PLIF,LIF,Laser-Induced Fluorescence,Rayleigh scattering,Laser Diagnostics,flame font,Combustion,Turbulence,Photofragmentation LIF,PF-LIF,Laser-induced Phosphorescence,LIP,Fysicumarkivet A:2012:Li},
  language     = {eng},
  pages        = {95},
  school       = {Lund University},
  title        = {Development and Application of Laser-Induced Emission Techniques for Combustion Diagnostics -High-Resolution Visualization of Turbulent Reacting Flows},
  year         = {2012},
}