Rayleigh Thermometry

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Rayleigh Thermometry

The analysis and optimization of combustion processes requires accurate measurement of several parameters including global temperature distribution. By using laser Rayleigh scattering, two-dimensional temperature maps can be derived from the resulting images from clean combustion and hot gas flows.

Rayleigh Thermometry data is obtained in a plane by illuminating the process under investigation with a thin laser light sheet. The elastically scattered light from the gas molecules is then recorded by an intensified CCD camera placed perpendicular to the light sheet. Since the intensity of the scattered light is directly related to the gas density, we can now use the grey level data from the images to determine the temperature.

Temperature profile of flame
Temperature profile of flame
Species and Mixtures libraries

To make the data analysis even more straightforward, the software also includes two libraries; one that includes several molecular species and their corresponding scattering cross-sections, and one that includes relevant mixtures of the species found in the first library. The global scattering cross-section for the gas mixtures is automatically calculated and the user only needs to define what mixture was used in the experiment, and the software takes the different scattering cross-sections into account in the data processing. Of course, the user is also allowed to add new species to the library and create new mixtures to create libraries tailor made for his specific applications.

LPG Gas
LPG-Gas-flame
LPG Gas Temperature Measurement

The software allows the user to edit and export groups of raw images, temperature and re-sampled maps into standard file formats. This simplifies the ability import the results to other custom analysis methods or to compare the data with numerical CFD results. Export facilities are designed to allow high flexibility with the format of the data (grid, metric or pixel coordinates system, number of precision digits for the scalar) in order to provide the user with data files that can be further processed without additional time-consuming modifications