Advanced

On the Use of Laser-Induced Incandescence for Soot Diagnostics: From Theoretical Aspects to Applications in Engines

Bladh, Henrik LU (2007)
Abstract
The laser-induced incandescence technique (LII) is a laser-based diagnostic technique for measurements of soot volume fraction and particle size. The technique relies on detection of incandescent light from soot particles heated to around 4000 K using nanosecond laser pulses.



A theoretical model for LII has been implemented and improved in order to provide a tool for predicting the signal response from soot particles when exposed to the laser pulse for various experimental conditions. Specifically, the model is capable of predicting the signal response from arbitrarily shaped measurement volumes defined by non-uniform spatial distribution of laser energy, and also from primary particle size distributions. The model has... (More)
The laser-induced incandescence technique (LII) is a laser-based diagnostic technique for measurements of soot volume fraction and particle size. The technique relies on detection of incandescent light from soot particles heated to around 4000 K using nanosecond laser pulses.



A theoretical model for LII has been implemented and improved in order to provide a tool for predicting the signal response from soot particles when exposed to the laser pulse for various experimental conditions. Specifically, the model is capable of predicting the signal response from arbitrarily shaped measurement volumes defined by non-uniform spatial distribution of laser energy, and also from primary particle size distributions. The model has been applied in order to investigate the influence of various physical and experimental parameters on evaluated primary particle size, the uncertainties introduced when measuring quantitative soot volume fractions in high-pressure environments using atmospheric calibration flames and on the relationship between the LII signal and the soot volume fraction. The model has also been applied in order to predict the appearance of experimentally obtained spatially resolved LII signals in a methane diffusion flame. The spatial distribution of laser energy, which has a profound influence on the LII signal behaviour, was measured using a beam profile CCD camera, the data being input to the model. A generally good agreement between theoretical and experimental data was found, but the results indicated that the theoretical model overpredicted the signal response at high fluence.



Two experimental investigations using laser diagnostics for in-cylinder measurements of internal combustion engines have been undertaken. In one of the studies the laser-induced fluorescence (LIF) technique was applied to measure the flame propagation inside a spark-ignition engine by detection of fluorescence from intermediate species in the end gas. Two Nd:YAG lasers operating at 355 nm and two ICCD detectors were used in order to provide two independent images of the unburnt gas region within single engine cycles. An image evaluation scheme was developed in order to evaluate the velocity field of the flame propagating inside the engine. In a second study the laser-induced incandescence technique was applied to measure quantitative soot volume fractions inside a high-speed direct-injection passenger car Diesel engine. The quantitative information was attained by relating the signals obtained in the engine to those obtained in a calibration flame. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Will, Stefan, Technische Thermodynamik, Universität Bremen, Germany
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Laser-Induced Incandescence, Laser Diagnostics, LII, Soot, Model, Engine, Particulates, Soot volume fraction, Combustion, Physics, Fysik, quantum mechanics, classical mechanics, Mathematical and general theoretical physics, Matematisk och allmän teoretisk fysik, thermodynamics, statistical physics, gravitation, relativity, kvantmekanik, klassisk mekanik, termodynamik, statistisk fysik, relativitet, Gases, Gaser, fluid dynamics, plasmas, Teknik, Laserteknik, Motors and propulsion systems, Motorer, framdrivningssystem, fluiddynamik, plasma, Technological sciences, Laser technology
pages
220 pages
publisher
Avdelningen för Förbränningsfysik, Fysiska Institutionen, Lunds Tekniska Högskola
defense location
Lecture Hall B, Department of Physics, Professorsgatan 1, Lund University Faculty of Engineering
defense date
2007-05-04 10:15
external identifiers
  • other:ISRN: LUTFD2/TFCP--07/119--SE
ISSN
1102-8718
ISBN
978-91-628-7142-0
language
English
LU publication?
yes
id
e8492aee-1be4-4eab-8a34-8b7b6001036a (old id 548433)
date added to LUP
2007-09-28 09:36:12
date last changed
2016-09-19 08:44:54
@phdthesis{e8492aee-1be4-4eab-8a34-8b7b6001036a,
  abstract     = {The laser-induced incandescence technique (LII) is a laser-based diagnostic technique for measurements of soot volume fraction and particle size. The technique relies on detection of incandescent light from soot particles heated to around 4000 K using nanosecond laser pulses.<br/><br>
<br/><br>
A theoretical model for LII has been implemented and improved in order to provide a tool for predicting the signal response from soot particles when exposed to the laser pulse for various experimental conditions. Specifically, the model is capable of predicting the signal response from arbitrarily shaped measurement volumes defined by non-uniform spatial distribution of laser energy, and also from primary particle size distributions. The model has been applied in order to investigate the influence of various physical and experimental parameters on evaluated primary particle size, the uncertainties introduced when measuring quantitative soot volume fractions in high-pressure environments using atmospheric calibration flames and on the relationship between the LII signal and the soot volume fraction. The model has also been applied in order to predict the appearance of experimentally obtained spatially resolved LII signals in a methane diffusion flame. The spatial distribution of laser energy, which has a profound influence on the LII signal behaviour, was measured using a beam profile CCD camera, the data being input to the model. A generally good agreement between theoretical and experimental data was found, but the results indicated that the theoretical model overpredicted the signal response at high fluence.<br/><br>
<br/><br>
Two experimental investigations using laser diagnostics for in-cylinder measurements of internal combustion engines have been undertaken. In one of the studies the laser-induced fluorescence (LIF) technique was applied to measure the flame propagation inside a spark-ignition engine by detection of fluorescence from intermediate species in the end gas. Two Nd:YAG lasers operating at 355 nm and two ICCD detectors were used in order to provide two independent images of the unburnt gas region within single engine cycles. An image evaluation scheme was developed in order to evaluate the velocity field of the flame propagating inside the engine. In a second study the laser-induced incandescence technique was applied to measure quantitative soot volume fractions inside a high-speed direct-injection passenger car Diesel engine. The quantitative information was attained by relating the signals obtained in the engine to those obtained in a calibration flame.},
  author       = {Bladh, Henrik},
  isbn         = {978-91-628-7142-0},
  issn         = {1102-8718},
  keyword      = {Laser-Induced Incandescence,Laser Diagnostics,LII,Soot,Model,Engine,Particulates,Soot volume fraction,Combustion,Physics,Fysik,quantum mechanics,classical mechanics,Mathematical and general theoretical physics,Matematisk och allmän teoretisk fysik,thermodynamics,statistical physics,gravitation,relativity,kvantmekanik,klassisk mekanik,termodynamik,statistisk fysik,relativitet,Gases,Gaser,fluid dynamics,plasmas,Teknik,Laserteknik,Motors and propulsion systems,Motorer,framdrivningssystem,fluiddynamik,plasma,Technological sciences,Laser technology},
  language     = {eng},
  pages        = {220},
  publisher    = {Avdelningen för Förbränningsfysik, Fysiska Institutionen, Lunds Tekniska Högskola},
  school       = {Lund University},
  title        = {On the Use of Laser-Induced Incandescence for Soot Diagnostics: From Theoretical Aspects to Applications in Engines},
  year         = {2007},
}