NOx emission and major species concentrations in partially premixed laminar methane/air co-flow jet flames

Gore, Jay P.; Zhan, Nian

doi:10.1016/0010-2180(95)00177-8

Cited by 115 publications

(50 citation statements)

References 17 publications

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“…Its main drawback is that it is a line-of-sight method and so inherently lacks spatial resolution. The third method to be mentioned is gas chromatography (GC) [26]. The techniques based on flame-sampling are typically employed to investigate stationary laminar flames at low pressure.…”

Section: Techniques Without Lasersmentioning

confidence: 99%

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Kiefer

Ewart

2011

Progress in Energy and Combustion Science

131

112

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Laser-based methods have transformed combustion diagnostics in the past few decades. The high intensity, coherence, high spectral resolution and frequency tunability available from laser radiation has provided powerful tools for studying microscopic processes and macroscopic phenomena in combustion by linear and nonlinear optical processes. This review focuses on nonlinear optical techniques based on resonant four-wave mixing for non-intrusive measurements of minor species in combustion. The importance of minor species such as reaction intermediates is outlined together with the challenges they present for detection and measurement in the hostile environments of flames, technical combustors, and engines. The limitations of conventional optical methods for such measurements are described and the particular advantages of coherent methods using nonlinear optical techniques are discussed.The basic physics underlying four-wave wave mixing processes and theoretical models for signal calculation are then presented together with a discussion of how combustion parameters may be derived from analysis of signals generated in various four-wave mixing processes. The most important four-wave mixing processes, in this context, are then reviewed:Degenerate Four-Wave Mixing (DFWM), Coherent Anti-Stokes Raman Scattering (CARS), Laser Induced Grating Spectroscopy (LIGS) and Polarization Spectroscopy (PS). In each case the fundamental physics is outlined to explain the particular properties and diagnostic advantages of each technique. The application of the methods mentioned to molecular physics studies of combustion species is then reviewed along with their application in measurement of concentration, temperature and other combustion parameters. Related nonlinear techniques and recent extensions to the ultra-fast regime are briefly reviewed. Finally practical considerations relevant to multi-dimensional and multi-species measurements, as well as applications in technical combustion systems are discussed.Keywords: nonlinear optical spectroscopy, four-wave mixing, combustion diagnostics, minor species detection, laser-induced gratings, polarization spectroscopy IntroductionEnergy from renewable sources such as solar and wind power is the goal of much current research and technological development. Combustion, however, is and is likely to remain for the foreseeable future, the most important energy source for heat, electrical power and especially for transportation. In technical combustion systems the chemical energy of fossil fuels such as coal, crude oil and natural gas is converted into heat through oxidation with oxygen from air. However, fossil fuel resources are limited and alternatives like biofuels [1] or novel technologies such as fuel cells [2] are not yet able to meet the demand. Consequently, for a sustainable use of fossil fuels it is desirable to further improve the efficiency, maintainability and reliability of existing combustion devices. Achieving such improvements depends upon an improved understanding of t...

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Section: Techniques Without Lasersmentioning

confidence: 99%

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Kiefer

Ewart

2011

Progress in Energy and Combustion Science

131

112

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“…It is worth noting that transient RANS (TRANS) can be used in place of LES (large eddy simulation) as it requires less computational time with reasonably good prediction of turbulent structures. In the present study the effect of radiation is neglected (just to reduce the time of computation) and it can be justified by fact that turbulent Energy ; (10) Species ; (11) Ri (Eddy break-up model) with A=4; B=0.5 (model constants)…”

Section: Simulation Detailsmentioning

confidence: 99%

“…With regard to their NO emission characteristics, Gore and x Zhan [11] performed a numerical investigation on the effect of partial premixing on NO production in x methane-air PPFs and observed the existence of an optimum level of partial premixing that yielded the lowest NO emission index. Tanoff et al [12] conducted a x numerical-experimental study of counter flow methane-air PPFs and observed a drastic change in NO x emission behavior as the flame changed from a merged-flame to a double-flame structure as the equivalence ratio (ö) was reduced below a certain threshold value.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation Of Diluent Effect On NOx Emission In A X Turbulent Premixed Methane Flames

Subramani¹,

Ambedkar²,

Babu³

2008

Int. Jour. Appl. Bio-Eng.

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The stringent requirement to reduce the NO from various combustion devices while maintaining the combustor x performance is of paramount motivation for the current study. Partially premixing, fuel blends and fuel diluents represents promising approaches for reducing NO from flames. A detailed two dimensional, transient numerical study on the later aspect of fuel diluents x (helium) to reduce the NO emission in a back ward facing step geometry has been carried out using CFX 5.7. The equivalence ratio x has been varied from 0.85-1, to study the effect of excess air on NO emission. The methane flame is simulated using Eddy break-up x model with Zeldovich thermal mechanism for NO formation and the turbulence model is w-RSS (Reynolds Shear Stress). The x simulation results indicate that considerable reduction in NO emission and increase in flame stability can be achieved for a x predetermined addition of inert in to the fuel air mixture.

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“…[21][22][23][24][25] and the references cited therein, mainly due to its greater relevance to many practical combustion processes including non-premixed combustion. One particularly interesting feature of partially premixed flames is the occurrence of double flame structure: an inner rich premixed flame enveloped by an outer diffusion flame [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Control of the structure and sooting characteristics of a coflow laminar methane/air diffusion flame using a central air jet: An experimental and numerical study

Liu

Smallwood

2011

Proceedings of the Combustion Institute

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NOx emission and major species concentrations in partially premixed laminar methane/air co-flow jet flames

Cited by 115 publications

References 17 publications

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Numerical Simulation Of Diluent Effect On NOx Emission In A X Turbulent Premixed Methane Flames

Control of the structure and sooting characteristics of a coflow laminar methane/air diffusion flame using a central air jet: An experimental and numerical study

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