Advanced laser-based measurement techniques provide new insights into physicochemical combustion processes. These techniques can visualise flame structures, detect flow relations in the combustion chamber, and can measure how the concentrations of combustion-relevant species are distributed and what temperatures are present. This requires a variety of diagnostic methods which mutually complement each other and are based on different physical processes. Unlike physical probes, these optical techniques permit the analysis of flames without influencing either the flow field in the combustion chamber or the complex chemical reactions that occur. Laser-based measurement techniques operate non-intrusively, with a high spatial and temporal resolution, and as light sheet techniques can also measure two-dimensional distributions. These techniques are mainly applied as single-pulse techniques, i.e. a full measurement is performed with each single, extremely short laser pulse. These are essential requirements for resolving the turbulent structures in the combustion zones and for obtaining precise and accurate information about the combustion process. Quantitative measurement data provide the experimental basis for testing and improving numerical simulation models, which nowadays are indispensable for improving the assessment of newly-designed combustion processes with respect to pollutant emissions and stability of the combustion process.
The workgroup mainly focuses on developing laser measurement techniques to address a wide range of combustion research issues.
Advancing laser-based measurement methods
The laser-based measurement methods detailed below are continuously being developed in order to adapt them to measurement requirements under special boundary conditions, including technical conditions, such as high pressure and real fuels.
Applications to technical systems
Outside the laboratory, the various measurement techniques are used in applications-based technical systems, and specifically to gas turbine combustion chambers. Experiments on such measurement objects are carried out on the Institute’s high-pressure test rig or on site for customers. The mobile measurement systems mentioned above are available for this purpose. Successful measurements have been carried out on
Priority research areas
In addition to improving methods and applying them to technical objects, the workgroup also addresses a number of issues in basic research. This work centres on improving our basic understanding of the combustion process being studied, such as soot formation in high-pressure combustion chambers, combustion behaviour of alternative fuels, ignition processes or combustion instabilities under special operating conditions such as lean premix combustion. Work is also being done to provide an extensive data basis for validation and improvement of numerical simulation models. To this end, standard flames are defined that are then studied using laser-based diagnostic methods.
Additional information about these standard flames can be found in the data archive of the Institute of Combustion Technology.