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Development of a 2D Temperature Measurement Technique for Combustion Diagnostics using 2-Line Atomic Fluorescence

Engström, Johan LU (2001) In Lund Reports on Combustion Physics 65.
Abstract (Swedish)
Popular Abstract in Swedish

Vid avdelningen bedrivs forskning bl.a. med inriktning på laserbaserad förbränningsdiagnostik. Att mäta med en laser i olika flammor är en stor fördel eftersom laserljuset är beröringsfritt. Därför kan unika mätresultat erhållas med en minimal påverkan av förbränningsprocessen. Jag har främst arbetar med att utveckla en teknik för att mäta temperaturen 2-dimensionellt. Att kunna bestämma temperaturen vid olika förbränningsprocesser är av stort intresse för att öka den grundläggande förståelsen av förbränning. Temperaturen ingår som en av de viktigaste variablerna i olika förbränningsmodeller.



Tekniken som jag har utvecklat är en två-linje linjär teknik. Vi seedar in ett känt... (More)
Popular Abstract in Swedish

Vid avdelningen bedrivs forskning bl.a. med inriktning på laserbaserad förbränningsdiagnostik. Att mäta med en laser i olika flammor är en stor fördel eftersom laserljuset är beröringsfritt. Därför kan unika mätresultat erhållas med en minimal påverkan av förbränningsprocessen. Jag har främst arbetar med att utveckla en teknik för att mäta temperaturen 2-dimensionellt. Att kunna bestämma temperaturen vid olika förbränningsprocesser är av stort intresse för att öka den grundläggande förståelsen av förbränning. Temperaturen ingår som en av de viktigaste variablerna i olika förbränningsmodeller.



Tekniken som jag har utvecklat är en två-linje linjär teknik. Vi seedar in ett känt ämne i förbränningsprocessen, i vårt fall indium. Ämnet exciteras med två olika laservåglängder och två fluorescens signaler erhålls som är proportionella mot en Boltzmannfördelning. Temperaturen kan sedan beräknas som en kvot mellan uppmätta storheter. Jag började med grundläggande flamstudier, för att studera olika parametrar mot signalstyrka. Efter de grundläggande undersökningarna byggde vi om en vanlig två-taktsmotor så att den fick optisk- access för att möjliggöra laserdiagnostik. Detta gjordes för att se om tekniken fungerade i en riktig motor, men under enklare förhållande. Resultatet blev så bra att tekniken användes i en optiskmotor på Volvo med lyckade resultat. Senare resultat visar även att tekniken kan användas i sotiga flammor som normalt är svårt för lasertekniker eftersom sotpartiklarna absorberar laserljuset. Detta öppnar för möjligheten att mäta temperaturen i dieselmotor och HCCImotorer. (Less)
Abstract
The present thesis is concerned with the development and application of a novel planar laser-induced fluorescence (PLIF) technique for temperature measurements in a variety of combusting flows. Accurate measurement of temperature is an essential task in combustion diagnostics, since temperature is one of the most fundamental quantities for the characterization of combustion processes. The technique is based on two-line atomic fluorescence (TLAF) from small quantities of atomic indium (In) seeded into the fuel. It has been developed from small-scale experiments in laboratory flames to the point where practical combustion systems can be studied. The technique is conceptually simple and reveals temperature information in the post-flame... (More)
The present thesis is concerned with the development and application of a novel planar laser-induced fluorescence (PLIF) technique for temperature measurements in a variety of combusting flows. Accurate measurement of temperature is an essential task in combustion diagnostics, since temperature is one of the most fundamental quantities for the characterization of combustion processes. The technique is based on two-line atomic fluorescence (TLAF) from small quantities of atomic indium (In) seeded into the fuel. It has been developed from small-scale experiments in laboratory flames to the point where practical combustion systems can be studied. The technique is conceptually simple and reveals temperature information in the post-flame regions. The viability of the technique has been tested in three extreme measurement situations: in spark ignition engine combustion, in ultra-lean combustion situations such as lean burning aero-engine concepts and, finally, in fuel-rich combustion. TLAF was successfully applied in an optical SI engine using isooctane as fuel. The wide temperature sensitivity, 700 – 3000 K, of the technique using indium atoms allowed measurements over the entire combustion cycle in the engine to be performed. In applications in lean combustion a potential problem caused by the strong oxidation processes of indium atoms was encountered. This limits measurement times due to deposits of absorbing indium oxide on measurement windows. The seeding requirement is a disadvantage of the technique and can be a limitation in some applications. The results from experiments performed in sooting flames are very promising for thermometry measurements in such environments. Absorption by hydrocarbons and other native species was found to be negligible. Since low laser energies and low seeding concentrations could be used, the technique did not, unlike most other incoherent optical thermometry techniques, suffer interferences from LII of soot particles or LIF from PAH. Furthermore, the technique is not affected by fluorescence quenching, which is an important feature compared to other techniques, since local quenching rates are difficult to assess, especially in turbulent combustion applications. All these facts make In-TLAF very attractive for thermometry applications in fuel-rich and turbulent combustion processes. In-TLAF may prove to be a good candidate for future measurements in diesel engines where temperature information is of crucial interest. The advantages of and problems associated with the technique are discussed, and critical comparisons with other techniques are made. Imaging processing software has been developed to automate the temperature evaluation process, and problems in assessing errors are discussed. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Dr Zizak, Giorgio, CNR-TeMPE via Cozzi 53, 201 25 Milano, Italy
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Laser technology, Elektronik och elektroteknik, Electronics and Electrical technology, PLIF, LIF, temperature measurements, TLAF, Laser diagnostic, combustion, Laserteknik, Motors and propulsion systems, Motorer, framdrivningssystem
in
Lund Reports on Combustion Physics
volume
65
pages
152 pages
publisher
Combustion Physics, Lund Institute of Technology
defense location
Fysiska Institutionen, Hörsal B
defense date
2001-03-30 13:15
ISSN
1102-8718
language
English
LU publication?
yes
id
890a79be-1975-4af7-9bbb-385453ec1e76 (old id 41428)
date added to LUP
2007-06-20 12:55:24
date last changed
2018-05-29 10:06:29
@phdthesis{890a79be-1975-4af7-9bbb-385453ec1e76,
  abstract     = {The present thesis is concerned with the development and application of a novel planar laser-induced fluorescence (PLIF) technique for temperature measurements in a variety of combusting flows. Accurate measurement of temperature is an essential task in combustion diagnostics, since temperature is one of the most fundamental quantities for the characterization of combustion processes. The technique is based on two-line atomic fluorescence (TLAF) from small quantities of atomic indium (In) seeded into the fuel. It has been developed from small-scale experiments in laboratory flames to the point where practical combustion systems can be studied. The technique is conceptually simple and reveals temperature information in the post-flame regions. The viability of the technique has been tested in three extreme measurement situations: in spark ignition engine combustion, in ultra-lean combustion situations such as lean burning aero-engine concepts and, finally, in fuel-rich combustion. TLAF was successfully applied in an optical SI engine using isooctane as fuel. The wide temperature sensitivity, 700 – 3000 K, of the technique using indium atoms allowed measurements over the entire combustion cycle in the engine to be performed. In applications in lean combustion a potential problem caused by the strong oxidation processes of indium atoms was encountered. This limits measurement times due to deposits of absorbing indium oxide on measurement windows. The seeding requirement is a disadvantage of the technique and can be a limitation in some applications. The results from experiments performed in sooting flames are very promising for thermometry measurements in such environments. Absorption by hydrocarbons and other native species was found to be negligible. Since low laser energies and low seeding concentrations could be used, the technique did not, unlike most other incoherent optical thermometry techniques, suffer interferences from LII of soot particles or LIF from PAH. Furthermore, the technique is not affected by fluorescence quenching, which is an important feature compared to other techniques, since local quenching rates are difficult to assess, especially in turbulent combustion applications. All these facts make In-TLAF very attractive for thermometry applications in fuel-rich and turbulent combustion processes. In-TLAF may prove to be a good candidate for future measurements in diesel engines where temperature information is of crucial interest. The advantages of and problems associated with the technique are discussed, and critical comparisons with other techniques are made. Imaging processing software has been developed to automate the temperature evaluation process, and problems in assessing errors are discussed.},
  author       = {Engström, Johan},
  issn         = {1102-8718},
  keyword      = {Laser technology,Elektronik och elektroteknik,Electronics and Electrical technology,PLIF,LIF,temperature measurements,TLAF,Laser diagnostic,combustion,Laserteknik,Motors and propulsion systems,Motorer,framdrivningssystem},
  language     = {eng},
  pages        = {152},
  publisher    = {Combustion Physics, Lund Institute of Technology},
  school       = {Lund University},
  series       = {Lund Reports on Combustion Physics},
  title        = {Development of a 2D Temperature Measurement Technique for Combustion Diagnostics using 2-Line Atomic Fluorescence},
  volume       = {65},
  year         = {2001},
}