|LASER-BASED COMBUSTION DIAGNOSTICS||FBR024|
The aim of the course is to provide a fundamental understanding (based on physics) of the potential for laser-based techniques to non-intrusively measure parameters such as species concentrations and temperatures in combustion processes. Of central importance is interaction between radiation and matter, lasers and their characteristics, optics, optical measurement techniques, molecular physics and combustion. The unique information that can be obtained from combustion processes using laser techniques can together with advanced modelling lead to improved detailed knowledge about combustion. Such understanding is highly important to improve efficiency and decrease harmful emissions, which is of global importance since 90% of the energy usage in the world can be related to combustion processes.
Knowledge and understanding
For a passing grade the student must
· be able to analyse the possibilities and limitations for these laser-based methods.
· be able to describe the advantages and disadvantages for laser-based methods in comparison with other methodsdescribe the advantages and disadvantages for laser-based methods in comparison with other methods.
Skills and abilities
For a passing grade the student must
· be able to design and build a simple experimental setup.
· be able to calculate parameters such as temperature, species concentration, and velocity from given measurement data.
· write reports from laboratory exercises with thorough analysis of measurement data and discussion about uncertainties.
· be able to write an extended abstract of a scientific paper in the laser diagnostic area and present it orally.
· be able to assimilate the important information in scientific papers of more basics character and in an advanced English text book.
· be able to solve problems with help from other sources than the course material, for example previous courses within the laser/optics area.
In the initial part of the course some topics are presented and discussed which for students with different backgrounds will mean repetition and extension to different degree. The areas that are treated are molecular spectroscopy, statistical physics, combustion, and experimental equipment for laser-based diagnostics. Comparison is performed between probe methods and optical methods. A detailed discuaaion is made of the most important methods for combustion diagnostics. They mainly include Rayleigh scattering, Raman scattering, laser-induced incandescence, laser-induced fluorescence, coherent anti-Stokes Raman spectroscopy, particle-image velocimetry and thermographic phosphors. The techniques are discussed from their physical background and the analysis of measurement data performed for evaluation of relevant parameters such as species concentrations, temperature, velocities, particle properties, etc. Emphasis is put on identifying the potential and the limitations of the techniques.
The scientific papers studied by the students in their projects should be close to the front line of research and present extensions of the already discussed techniques. Orientation about new techniques developed within the research field is made. Frequently during course demonstrations are made in the research laboratories of the division to illustrate different parts of the course.
The laboratory exercises are laser-induced incandescence(LII) and laser-induced fluorescence (LIF). The laboratory exercise on LII treats measurements of soot concentrations in flames, and the one in LIF treats visualisation of flame radicals. Both exercises are relatively student-oriented where the students take relatively big part in the alignment and optimisation of the experimental setup.
Eckbreth, A.C: Laser Diagnostics for Combustion Temperature and Species, Gordon and Breach, 1996 and additional text.