Optical probe for in-situ measurements of air-to-fuel ratio in low emission engines

Mongia, Rajiv; Tomita, Eiji; Hsu, Frank K.; Talbot, L.; Dibble, Robert W.

doi:10.2514/6.1996-174

Cited by 7 publications

(4 citation statements)

References 11 publications

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“…This technique can be considered as essentially non-intrusive since the length scale of the seed particles is less than the Kolmogorov scale of turbulence in the experimental flow. Mongia et al (1996) discuss the development and validation (at pressures up to 10 atm in cold C114/air flow) of an inexpensive optical probe technique which measures fuel concentration directly via He-Ne laser absorption. Spatial resolution considerations require use of fiber optics, so this method is intrusive.…”

Section: Optical Techniquesmentioning

confidence: 99%

Quantifying Unmixedness in Lean Premixed Combustors Operating at High Pressure, Fired Conditions

Barnes

Mellor

1997

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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Lean premixed combustor manufacturers require premixer concepts that provide homogeneity (mixechtess) of the fuel which burns in the main flame. Ideally prernixer evaluation would be conducted under realistic combustor operating conditions. However, current techniques typically are limited to cold-flow, low pressure (<14 atm) conditions or comparison of measured NOx emissions with others obtained in premixed systems. Thus, a simple, consistent method for quantifying unmixedness in lean premixed combustors operating at high pressure, fired operating conditions is proposed here, using the characteristic time model developed in the companion paper.

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Section: Optical Techniquesmentioning

confidence: 99%

Quantifying Unmixedness in Lean Premixed Combustors Operating at High Pressure, Fired Conditions

Barnes

Mellor

1997

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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“…This is based a on line-of-sight absorption/extinction method and uses the difference in infrared absorption spectra to discriminate between the gas and liquid phases. One of major concerns with this technique, associated with its application to an actual turbine combustor, is that because the absorption coefficient is on the order of 10 atmcm' for most hydrocarbons [3][4], optical path lengths as small as 1 mm or less are typically required.…”

Section: Introductionmentioning

confidence: 99%

<title>Fiber optic probe for primary zone fuel distribution measurements in actual liquid-fueled gas turbine combustors</title>

Lee

Santavicca

1999

SPIE Proceedings

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A laser induced fluorescence (LIF)-based optical fiber probe has been developed for spatially and temporally resolved measurements of the equivalence ratio in actual gas turbine combustors. By using the probe to simultaneously detect laser induced fluorescence and Mie-scattering, its applicability has been extended to liquid-fueled combustors. The probe has been tested in a simple flow system consisting of a four-inch diameter flow tube with a spray nozzle at the center and Jet-A as the fuel. PDPA(Phase Doppler Particle Analyzer) measurements are made to correlate the Mie-scattering signal with the number density of liquid droplets. The results indicate that the probe can be used for qualitative characterization of liquid fuel vaporization, and that quantitative measurement of fuel vapor concentration in liquid-fueled gas turbine combustion is possible with calibration of the temperature dependence of the fluorescence.

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“…The NO x and CO emissions are influenced by the extent of mixing of the fuel and air, so that the inhomogeneity of the fuel-air mixture can be measured using an infrared absorption method. Local fuel concentrations have been determined near the burner outlet using infrared fibres; however, the inhomogeneities have increased the NO x emissions in lean mixtures with an overall equivalence ratio of 0.6 [5,6]. Lee et al [7] used an infrared absorption technique based on measurements of the equivalence ratio in an experimental study of the coupling between the pressure and heat release fluctuations during lean premixed unstable combustion.…”

Section: Introductionmentioning

confidence: 99%

In situmeasurement of hydrocarbon fuel concentration near a spark plug in an engine cylinder using the 3.392 m infrared laser absorption method: discussion of applicability with a homogeneous methane–air mixture

Tomita

Kawahara

Shigenaga

et al. 2003

Meas. Sci. Technol.

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A fibre optic system was developed to determine the fuel concentration near a spark plug using an infrared absorption method. The system was linked to an optical sensor installed in the spark plug, from which light could pass through the combustion chamber. By using this modified spark plug, successive measurements of the fuel concentration near the spark plug before ignition were performed in a spark-ignition engine burning homogeneously mixed methane-air. The fuel concentration was determined from the Lambert-Beer law by considering the dependence of the methane molar absorption coefficient on pressure and temperature. Three main conclusions were drawn from this study. First, the methane molar absorption coefficient was greater for lower pressures and decreased with increasing temperature and pressure above atmospheric pressure. The temperature and pressure effects were offset by each other, since the temperature effects were positive and the pressure effects were negative. Second, precise time-series data for the local fuel concentration were obtained by considering the in-cylinder pressure and temperature from an estimate of the methane molar absorption coefficient. And third, the measured air/fuel ratio near the spark plug before ignition agreed with the preset value when the developed optical sensor was used under motoring and firing conditions.

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Optical probe for in-situ measurements of air-to-fuel ratio in low emission engines

Cited by 7 publications

References 11 publications

Quantifying Unmixedness in Lean Premixed Combustors Operating at High Pressure, Fired Conditions

Quantifying Unmixedness in Lean Premixed Combustors Operating at High Pressure, Fired Conditions

<title>Fiber optic probe for primary zone fuel distribution measurements in actual liquid-fueled gas turbine combustors</title>

In situmeasurement of hydrocarbon fuel concentration near a spark plug in an engine cylinder using the 3.392 m infrared laser absorption method: discussion of applicability with a homogeneous methane–air mixture

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