Alkaline Earth Metal Imaging
We have demonstrated that light emissions from combinations of thermally-excited alkali atoms can yield information about temperature and equivalence ratios under internal combustion engine conditions. This opens opportunities for fast imaging diagnostics that is also accessible for use with endoscopic optical access.
Details are described in the following publication:
Michael Mosburger, Volker Sick and Michael C Drake
Quantitative high-speed imaging of burned gas temperature and equivalence ratio in internal combustion engines using alkali metal fluorescence.
International Journal of Engine Research 2014 15: 282, DOI: 10.1177/1468087413476291
The concept described above is currently being expanded to simplify the method to using fewer seed species and to include auto-calibration features that will enhance the accuracy of the results.
NSF is funding this effort "Alkaline earth metal enabled scalar imaging for high-pressure combustion"
This project will use the spontaneous light emission from thermally-excited combustion products of an alkaline earth metal, specifically those of strontium, to develop a diagnostic tool for measuring temperature and equivalence ratio in high-temperature and high-pressure environments. Applications of this technique will enable advances in three-dimensional imaging diagnostics, enhance the fundamental understanding of combustion, and support the development of advanced combustion technologies by lowering the complexity and the cost of the experiments. The physical processes that control the light emission depend on a range of factors and their influence will be studied to enable the quantitative analysis of the light emissions from the flames. The fundamental studies will be carried out in laboratory burners and optical research engines. This effort will result in a model that can quantitatively describe the light emission under combustion conditions. Then, experimental applications will be demonstrated in modern direct-injection engines. These experiments will make use of endoscopes as well as multiple highspeed cameras or lightfield cameras, which can facilitate novel three-dimensional imaging.