Lean Blowout with a High Pressure Well Stirred Reactor

Gross, Justin T.; Shouse, Dale T.; Neuroth, Craig

doi:10.2514/6.2016-4899

Cited by 1 publication

(2 citation statements)

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“…LBO testing and emissions sampling were performed in a toroidal jet-stirred reactor (TJSR) following the original design of Nenniger and the later modifications by Zelina and then Stouffer. ,,,, Experimental conditions for the TJSR are similar to those of typical gas turbine combustors. , Experimental inlet temperatures and residence times are on the same order of magnitude when comparing the TJSR and gas turbine combustors as indicated in Table . Elevated pressures have been used in prior assessments of LBO in a TJSR; however, near atmospheric pressure operation was selected for this work. Although the volume is smaller than that of gas turbine combustors, the TJSR is meant to be an idealized primary zone, which is less volume overall than an annular combustor sector or can.…”

Section: Methodsmentioning

confidence: 99%

“…38,55 Experimental inlet temperatures and residence times are on the same order of magnitude when comparing the TJSR and gas turbine combustors as indicated in Table 1. Elevated pressures have been used in prior assessments of LBO in a TJSR; 63 however, near atmospheric pressure operation was selected for this work. Although the volume is smaller than that of gas turbine combustors, the TJSR is meant to be an idealized primary zone, which is less volume overall than an annular combustor sector or can.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Lean Blowoff in a Toroidal Jet-Stirred Reactor: Implications for Alternative Fuel Approval and Potential Mechanisms for Autoignition and Extinction

et al. 2020

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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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