Abstract:A system for three-dimensional computed tomography of chemiluminescence was developed to measure flames over a large field angle. Nine gradient-index rods, with a 9 × 1 endoscope and only one camera are used. Its large field of view, simplicity, and low cost make it attractive for inner flow field diagnostics. To study the bokeh effect caused by the imaging system on reconstruction solutions, fluorescent beads were used to determine the blurring function. Experiments using a steady diffusion flame were conducted to validate the system. Three models, namely the clear-imaging, out-of-focus imaging, and deconvolution models, were utilized. Taking the bokeh effect into account, the results suggest that based on run-times the deconvolution model provides the best reconstruction accuracy without increasing computational time.
Quantitative measurements of chemiluminescence emissions as a result of CH*, OH*, C 2 *, and CO 2 * were conducted in CH 4 /air premixed flames at different equivalence ratios (θ = 0.7−1.33), and numerical results based on onedimensional flame simulations were compared to these data. A wavelength-dependent and optical-path-corrected emission calibration method was applied to quantify the emission of each excited species. The numerically simulated emission intensities of OH* and CH* are within the same order of magnitude as the experimental values for the same flame conditions. When selfabsorption and cooling water thermosteresis are taken into account, the simulated OH* values are 1.0−1.4 times greater than the experimental results, while the CH* values are approximately 2.3−4.1 times greater. These findings suggest that more work is required to refine the temperature dependence factors for the CH* formation rate coefficients at high temperatures.
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.