The optical emissions from a turbulent, nonpremixed, liquid fueled (n-heptane) combustor were investigated using two optical imaging systems: a high spectral resolution (~0.3 nm), single wavelength system; and a low resolution (~5 nm), multi-wavelength system intended to mimic the response of a practical sensor. The goal was to develop signal interpretation strategies that would allow an optical sensor system to monitor needed properties in liquid-fueled combustors and engines. The research focused on the chemiluminescent emissions from OH*, CH*, and C 2 *. Data were acquired for a range of fuel and air flow rates (equivalence ratios 0.6-1.3), and for radial slices through the nominally axisymmetric combustor over the complete combustor length. Without correction, both OH* and CH* emission were found to be good indicators of heat release rate only over a narrow band of lean equivalence ratios. In addition, OH* provides information on the postcombustion zone conditions. A nearly linear relationship was found between the overall equivalence ratio of the combustor and the ratio of the emission integrated over the combustor volume from two radical species, with the ratio C 2 */OH* exhibiting the greatest sensitivity. The correlation was also applied to estimate the radially averaged equivalence ratio of the reaction zone along the length of the combustor. With the multiwavelength sensor set to simultaneously monitor the broadband background from the flame, its background corrected output agreed well with the high spectral resolution results, suggesting that a properly designed optical sensor system would be capable of determining local combustor conditions such as reaction zone equivalence ratio and heat release rate.
Abstract—
Proton‐made spectroscopy was performed on solutions of l‐tryptophan and 8‐mcthoxypsoralen (8‐MOP) in either D2O or DMSO‐d6 in the presence of oxygen before and after irradiation with 360 nm monochromatic light. Irradiation results in the loss of hydrogen atoms at the 3. 4 and 4′. 5′ positions of 8‐MOP and at the indole C2 position of tryptophan. Changes in the aliphatic regions of the spectra also occur with irradiation. It is postulated that generation of photoreaction products between 8‐MOP and tryptophan involves the 3.4 and 4′.5′ positions of 8‐MOP and the imidazole moiety of tryptophan.
Reprint requests to: Dr J. Megaw, Laboratory for Ophthalmic Research, Emory University School of Medicine, Atlanta. Georgia 30322. USA.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.