| In order to design cleaner and more efficient practical combustion devices, such as engines and gas turbines, fundamental understanding of combustion processes, accurate diagnostic techniques and computational models are required. Optical diagnostic techniques, being non-intrusive and in-situ, are a powerful tool for characterizing combustion systems.;A color-ratio pyrometry technique using a consumer digital single lens reflex camera was developed with single-shot measurement capabilities. The technique was found to work well with SiC fibers and soot for flame temperature and soot volume fraction measurements. A novel absolute light intensity calibration method using S-type thermocouples was also developed, which offers a robust and low-cost alternative solution for traditional calibration approaches, for example expensive blackbody sources and calibrated tungsten lamps. The developed diagnostic techniques have been applied in microgravity combustion experiments completed on the International Space Station; the measured results provide ideal test cases free from buoyancy effects to improve the current computational models.;Soot radius of gyration in the Yale standard coflow laminar diffusion flames has been measured in two dimensions by using the newly developed 2-D multi-angle light scattering technique. Extinction has also been measured by a spectrally resolved line-of-sight attenuation method. These measurements further complete our understanding of soot formation, provide insights on spectral emissivities of soot at different aging stages (e.g., young soot or mature soot), and were shown to improve the accuracy of soot color-ratio pyrometry measurements. |
