Computed Tomography of Chemiluminescence (CTC): High resolution and instantaneous 3-D measurements of a Matrix burner

Computed Tomography of Chemiluminescence (CTC) is a diagnostic technique that provides instantaneous 3-D information on flame geometry and excited species concentrations. The technique reconstructs the 3-D chemiluminescence intensity field using Computed Tomography (CT) from integral measurements of chemiluminescence in the form of camera images. The CTC sensor has been demonstrated for a methane–oxygen Matrix burner consisting of 21 laminar diffusion jet flames using affordable commodity cameras. High resolution 3-D reconstructions obtained from 48 views show good agreement with the observed flame shape and resolve wavelengths of approximately 220 μm. This is sufficient to capture the multiple flame fronts, showing the suitability of CTC for wrinkled turbulent flames. Instantaneous 3-D reconstructions using 10 simultaneous camera measurements also show good agreement with the observed flame shape and are seen to be tolerant of error in the camera location. Measurements with exposure times as short as 62 μμs were found to achieve more than sufficient signal-to-noise ratios for successful tomographic reconstructions. Obvious applications for CTC are the measurement of (instantaneous) flame-surface density, wrinkling factor, flame normal direction, and possibly heat release, as well as the observation of transient developments.