Conference proceeding
Characteristic Timescales for Lean Blowout of Alternative Jet Fuels (AIAA 2018-4914)
American Institute of Aeronautics and Astronautics. AIAA Conference Papers
Joint Propulsion Conference (Cincinnati, Ohio, 07/09/2018–07/11/2018)
01/01/2018
Handle:
https://hdl.handle.net/2376/120556
Appears in Aviation Sustainability Center (ASCENT)
Abstract
The National Jet Fuels Combustion Program, focused on reducing the time and cost for the approval process of alternative jet fuels, has found a first order dependence on derived cetane number in predicting lean blowout for most of the combustor rigs in the program. However the sensitivity of LBO on DCN is dependent on the rig and operating conditions. Additionally, it has been observed that at least one rig has shown no correlation with the derived cetane number and lean blowout. It is hypothesized that these observations can be explained via timescale analysis considering fuel evaporation, combustor mixing, and chemical reactivity timescales. This paper combines this timescale theory with reduced order random forest regression properties to represent each of the previously identified timescales. Evaporative timescales are estimated via a fuel’s density and 20% recovered temperature to represent spray quality/atomization and evaporative potential, respectively. Autoignition and extinction chemical timescales are estimated by a fuel’s derived cetane number and radical index, respectively. Random forest regressions with only these four properties are able to account for better than 89% of experimental variance in four diverse rigs and hundreds of data points. Applying these results to timescale theory corroborates previous observations. Rigs with minimal fuel atomization spray differences are minimally sensitive to evaporative timescales. Alternatively, the rig with the most reported sensitivity to viscosity, a Honeywell Auxiliary Power Unit type rig, also shows the most sensitivity to atomization and evaporative timescales. The fourth rig studied from the University of Sheffield shows a near equivalent dependency on chemical and evaporative timescales. These simplified regressions illustrate how four fuel properties, representative of each timescale, are able to accurately capture the physics dominating LBO for each rig, and in turn could reduce the time and costs for the approval of alternative jet fuels.
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Details
- Title
- Characteristic Timescales for Lean Blowout of Alternative Jet Fuels (AIAA 2018-4914)
- Creators
- Erin E. Peiffer - University of DaytonJoshua S. Heyne - University of DaytonMeredith B. Colket
- Publication Details
- American Institute of Aeronautics and Astronautics. AIAA Conference Papers
- Conference
- Joint Propulsion Conference (Cincinnati, Ohio, 07/09/2018–07/11/2018)
- Academic Unit
- Aviation Sustainability Center (ASCENT); Alternative Jet Fuel
- Publisher
- American Institute of Aeronautics and Astronautics
- Grants
- 13-C-AJFE-UD-013, Federal Aviation Administration (United States, Washington) - FAA
- Identifiers
- 99900621893901842
- Language
- English
- Resource Type
- Conference proceeding