Flame stabilization behavior is experimentally investigated at engine relevant conditions using an optical sensor imaging system. Optical imaging systems can provide insight into local engine behavior as opposed to measurements with devices such as flowmeters. Two facilities are utilized to examine premixed flame combustion stabilized by bluff body flame holders at both atmospheric and elevated pressures. C2* and CH* chemiluminescence signals are recorded on a four-band imaging system to calibrate the sensor intensity ratio of C2*/CH* to the flame equivalence ratio. Tracking this ratio across flame position can provide local information concerning flow disturbances and other combustor instabilities. Several fuels (methane, propane, and liquid Jet-A) are tested to examine the change in chemiluminescence ratios that can be found in industrial applications. The calibrations are obtained across a wide range of equivalence ratios (0.6-1.4) and for pressures of 1 and 5 bar. Methane flames showed very low C2* signal value in lean and stoichiometric flames, resulting in non-monotonically increasing calibration curves. Propane flames had a monotonic calibration curve, attributed to greater C2* signal intensity. The Jet-A-air flames also had non-monotonically increasing calibrations at 1 bar, but a monotonic curve at elevated pressure. These calibrations are then applied to the average C2*/CH* intensity ratio images to yield maps of flame equivalence ratio. Downstream variation in the equivalence ratio of the unconfined facility is attributed to air entrainment, while in the weaker signal is thought to be a function of the local flame properties.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd2020-2101 |
| Date | 01 January 2022 |
| Creators | Tonarely, Michael |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations, 2020- |
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