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Development of Time Resolved Laser Imaging Techniques for Studies of Turbulent Reacting Flows

Hult, Johan LU (2002)
Abstract
In the present thesis the development and application of a novel laser diagnostic system for high speed spectroscopic imaging of turbulent combustion phenomena is presented. The system is capable of recording sequences of up to 8 images with a separation between consecutive images as short as microseconds. The system allows a number of established laser diagnostic techniques to be used, extending them into the time resolved regime. For the first time it has thus become possible to observe the influence of fluid motion or reaction chemistry on flame structure in a direct, time resolved, fashion. The high speed diagnostic system has been used to study flame species and fuel distributions with a high temporal resolution in jet flames,... (More)
In the present thesis the development and application of a novel laser diagnostic system for high speed spectroscopic imaging of turbulent combustion phenomena is presented. The system is capable of recording sequences of up to 8 images with a separation between consecutive images as short as microseconds. The system allows a number of established laser diagnostic techniques to be used, extending them into the time resolved regime. For the first time it has thus become possible to observe the influence of fluid motion or reaction chemistry on flame structure in a direct, time resolved, fashion. The high speed diagnostic system has been used to study flame species and fuel distributions with a high temporal resolution in jet flames, combustion cells and in IC engines.



In jet flames various flame instability mechanisms, like local flame extinction and flame lift-off have been studied. Large scale structures have been observed and tracked in time, using time resolved planar laser induced fluorescence (PLIF) imaging of the OH radical. Individual extinction phenomena have been studied in further detail by simultaneous measurements of the velocity field at the flame front, allowing correlations between flow and flame structures to be made. Vortices impinging on the flame front from the fuel side were found to be the main extinction mechanism, and the time scale of the extinction process could be estimated.



High speed imaging has also been applied to study novel combustion engine concepts, like the homogeneous charge compression ignition (HCCI) engine. True single-cycle resolved measurements allows the evolution of single fuel injection, ignition or combustion events to be followed in time, and cycle-to-cycle variations of complex phenomena to be studied. In an HCCI engine the appearance and growth of multiple auto-ignition kernels was observed. Following ignition the fuel was found to be consumed gradually, at different rates in different regions, and not through propagating flame fronts as is the case in spark ignition engines.



By rapidly displacing the eight laser beams through a measurement volume using a scanning mirror, three-dimensional (3-D) measurements also become possible. This technique has been demonstrated in both flames and engines, allowing flame topology or 3-D concentrations gradients to be studied. In addition to the experimental work, advanced image processing routines have also been developed and applied for automatic data enhancement and analysis. (Less)
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author
supervisor
opponent
  • Prof Long, Marshall, Yale University
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Electronics and Electrical technology, Laserteknik, Elektronik och elektroteknik, Laser technology, Fysik, Physics, Three-dimensional, Laser Diagnostics, High speed, Fysicumarkivet A:2002:Hult
pages
288 pages
publisher
Department of Combustion Physics, Lund University
defense location
Lecture hall B, Dep. of Physics
defense date
2002-03-22 10:15:00
external identifiers
  • other:ISRN: LUTFD2/TFCP--74-SE
language
English
LU publication?
yes
additional info
Article: I. C.F. Kaminski, J. Hult and M. Aldén“High repetition rate planar laser induced fluorescence of OH in a turbulent non-premixed flame”Applied Physics B 68, 757-760, 1999 Article: II. J. Hult, G. Josefsson, M. Aldén and C.F. Kaminski“Flame front tracking and simultaneous flow field visualisation in turbulent combustion”Proceedings of the 10th International Symposium on Applications of Laser Techniques to Fluid Mechanics, Paper No. 26-2, (Instituto Superior Técnico, Lisbon, 2000) Article: III. T. Ding, Th.H. van der Meer, M. Versluis, M. Golombok, J. Hult, M. Aldén and C.F. Kaminski“Time-resolved PLIF measurements in turbulent diffusion flames”Proceedings of the 3rd International Symposium on Turbulence, Heat and Mass Transfer, vol. 3, 857-864, (Aichi Shuppan, Japan, 2000) Article: IV. J. Hult, A. Omrane, J. Nygren, C.F. Kaminski, B. Axelsson, R. Collin, P.-E. Bengtsson and M. Aldén“Quantitative Three-Dimensional Imaging of Soot Volume Fraction in Turbulent Non-Premixed Flames”in press, Experiments in fluids Article: V. A. Dreizler, S. Lindenmaier, U. Maas, J. Hult, M. Aldén and C.F. Kaminski“Characterization of a spark ignition system by planar laser-induced fluorescence of OH at high repetition rates and comparison with chemical kinetic calculations”Applied Physics B 70, 287-294, 2000 Article: VI. C.F. Kaminski, X.S. Bai, J. Hult, A. Dreizler, S. Lindenmaier and L.Fuchs“Flame growth and wrinkling in a turbulent flow”Applied Physics B 71, 711-716, 2000 Article: VII. C.F. Kaminski, J. Hult, M. Aldén, S. Lindenmaier, A. Dreizler, U. Maas and M. Baum“Spark ignition of turbulent methane/air mixtures revealed by time-resolved planar laser-induced fluorescence and direct numerical simulations”Proceedings of the 28th Symposium on Combustion, 399-405, (The Combustion Institute, Pittsburgh, 2000) Article: VIII. C.F. Kaminski, J. Hult, M. Richter, J. Nygren, A. Franke, M. Aldén, S. Lindenmaier, A. Dreizler, U. Maas and R.B. Williams“Development of high speed spectroscopic imaging techniques for the time resolved study of spark ignition phenomena”SAE paper No. 2000-01-2833 (The Society of Automotive Engineers, Warrendale, PA, 2000)approved for SAE Transactions - Journal of Fuels & Lubricants Article: IX. J. Hult, M. Richter, J. Nygren, M. Aldén, A. Hultqvist, M. Christensen and B. Johansson“Application of a high speed laser diagnostic system for single-cycle resolved imaging in IC engines”submitted to Applied Optics Article: X. J. Nygren, M. Richter, J. Hult, C.F. Kaminski and M. Aldén“Temporally resolved single cycle measurements of fuel- and OH-distributions in a spark ignition engine using high speed laser spectroscopy”Proceedings of the 5th International Symposium on Diagnostics and Modelling of Combustion in Internal Combustion Engines (COMODIA), 572-580, (Japan Society of Mechanical Engineers, Japan, 2001) Article: XI. A. Hultqvist, M. Christensen, B. Johansson, M. Richter, J. Nygren, J. Hult and M. Aldén“The HCCI Combustion Process in a Single Cycle - High-Speed Fuel Tracer LIF and Chemiluminescence Imaging”SAE paper No. 2002-01-0424 (The Society of Automotive Engineers, Warrendale, PA, 2000) Article: XII. J. Nygren, J. Hult, M. Richter, M. Aldén, M. Christensen, A. Hultqvist and B. Johansson“Three-dimensional Laser Induced Fluorescence of Fuel Distributions in an HCCI Engine”submitted to the 29th International Symposium on Combustion Article: XIII. H. Malm, G. Sparr, J. Hult and C.F. Kaminski“Nonlinear diffusion filtering of images obtained by planar laser induced fluorescence spectroscopy”Journal of the Optical Society of America A 17, 2148-2156, 2000
id
f7d9ab9c-77ac-4caa-8a57-f6ea5dbc4265 (old id 464416)
date added to LUP
2016-04-01 16:19:42
date last changed
2018-11-21 20:40:32
@phdthesis{f7d9ab9c-77ac-4caa-8a57-f6ea5dbc4265,
  abstract     = {In the present thesis the development and application of a novel laser diagnostic system for high speed spectroscopic imaging of turbulent combustion phenomena is presented. The system is capable of recording sequences of up to 8 images with a separation between consecutive images as short as microseconds. The system allows a number of established laser diagnostic techniques to be used, extending them into the time resolved regime. For the first time it has thus become possible to observe the influence of fluid motion or reaction chemistry on flame structure in a direct, time resolved, fashion. The high speed diagnostic system has been used to study flame species and fuel distributions with a high temporal resolution in jet flames, combustion cells and in IC engines.<br/><br>
<br/><br>
In jet flames various flame instability mechanisms, like local flame extinction and flame lift-off have been studied. Large scale structures have been observed and tracked in time, using time resolved planar laser induced fluorescence (PLIF) imaging of the OH radical. Individual extinction phenomena have been studied in further detail by simultaneous measurements of the velocity field at the flame front, allowing correlations between flow and flame structures to be made. Vortices impinging on the flame front from the fuel side were found to be the main extinction mechanism, and the time scale of the extinction process could be estimated.<br/><br>
<br/><br>
High speed imaging has also been applied to study novel combustion engine concepts, like the homogeneous charge compression ignition (HCCI) engine. True single-cycle resolved measurements allows the evolution of single fuel injection, ignition or combustion events to be followed in time, and cycle-to-cycle variations of complex phenomena to be studied. In an HCCI engine the appearance and growth of multiple auto-ignition kernels was observed. Following ignition the fuel was found to be consumed gradually, at different rates in different regions, and not through propagating flame fronts as is the case in spark ignition engines.<br/><br>
<br/><br>
By rapidly displacing the eight laser beams through a measurement volume using a scanning mirror, three-dimensional (3-D) measurements also become possible. This technique has been demonstrated in both flames and engines, allowing flame topology or 3-D concentrations gradients to be studied. In addition to the experimental work, advanced image processing routines have also been developed and applied for automatic data enhancement and analysis.},
  author       = {Hult, Johan},
  language     = {eng},
  publisher    = {Department of Combustion Physics, Lund University},
  school       = {Lund University},
  title        = {Development of Time Resolved Laser Imaging Techniques for Studies of Turbulent Reacting Flows},
  year         = {2002},
}