Journal article
Lean Blowoff in a Toroidal Jet-Stirred Reactor: Implications for Alternative Fuel Approval and Potential Mechanisms for Autoignition and Extinction
Energy & fuels, Vol.34(5), pp.6306-6316
05/21/2020
Handle:
https://hdl.handle.net/2376/121105
Appears in Aviation Sustainability Center (ASCENT)
Abstract
Sustainable aviation fuels (SAFs) have been identified as a method to reduce the aviation sector’s environmental impact through carbon mitigation. Current certification processes of potential, viable SAFs require labor cost intensive assessments with investigation into combustor performance parameters related to fuel effects such as lean blowoff (LBO) where there exists the competition between multiphase physics and chemical kinetics of the fuel. Recent efforts show LBO effectively scales with the evaporative, mixing, and chemical time scales of a given combustor. Here, a toroidal jet-stirred reactor (TJSR), an experimental configuration meant to emulate perfectly stirred reactor (PSR) studies, is used to study the effects of fuel chemistry physical time scales on LBO while mitigating and minimizing the effects of evaporation mixing, respectively. For this investigation, six fuels/fuel mixtures spanning a range of derived cetane number (DCN) were evaluated in a lean premixed, prevaporized environment with engine relevant characteristics such as recirculation inlet temperature residence times (P = ∼1 atm, T = 460 K, τ = 5.5–6.5 ms). Gas phase emissions sampled within the reactor were measured with a Fourier transform infrared spectrometer to gain insight into relevant trends in species production for varying fuels as leaner conditions were approached. LBO in the TJSR was correlated with the parameters of the DCN and radical index, an indicator of OH production, signifying competition between the chemical processes of autoignition and extinction, respectively; these observations deviate from the established PSR theory for ignition extinction physics. However, the emergence of these correlations in the TJSR experiment support the importance of low temperature chemistry and flame robustness. A physical time scale approach to LBO is applied to the current experiment to elucidate the competition of autoignition and extinction phenomena. Knowledge of the physical LBO time scales and their relationship to chemical fuel properties suggest that the holistic LBO time scale may be viable as a preliminary screening metric for SAF certification.
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Details
- Title
- Lean Blowoff in a Toroidal Jet-Stirred Reactor: Implications for Alternative Fuel Approval and Potential Mechanisms for Autoignition and Extinction
- Creators
- Robert Stachler - University of Dayton, Dayton, Ohio 45469, United StatesJoshua Heyne - University of DaytonScott Stouffer - University of DaytonJoseph Miller - Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
- Publication Details
- Energy & fuels, Vol.34(5), pp.6306-6316
- Academic Unit
- Aviation Sustainability Center (ASCENT); Alternative Jet Fuel
- Grants
- 13-C-AJFE-UD-13, Federal Aviation Administration (United States, Washington) - FAA
- Identifiers
- 99900621893701842
- Language
- English
- Resource Type
- Journal article