Thermal radiation properties of turbulent lean premixed methane air flames

Ji, Jun; Sivathanu, Yudaya; Gore, Jay P.

doi:10.1016/s0082-0784(00)80235-0

Cited by 34 publications

(9 citation statements)

References 25 publications

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“…7 15 µm β-SiC fibers, InGaAs point detectors (sensitive to wavelengths of 900 -1600 nm), rotating mirrors and calibration using a steady flame of known temperature. Other researchers also have performed TFP using single-element infrared detectors using either a monochromator or rotating mirrors (or prisms) or traversable flames (or optics) [7][8][9][10][11][12][13][14].…”

mentioning

confidence: 99%

Thin-filament pyrometry with a digital still camera

2007

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A novel thin-filament pyrometer is presented here. It involves a consumer-grade color digital still camera with a charged-couple device sensor with 3008 × 2000 pixels and 12 bits per color plane. A blue Schott filter and custom white balance were used to yield similar red, green and blue intensities along the fibers. SiCO fibers with diameters of 13.9 µm were used and scanning-electron microscopy revealed the fibers to be uniform. Measurements were performed in a methane/air coflowing laminar jet diffusion flame with a luminosity length of 72 mm. Calibration of the pyrometer was accomplished with B-type thermocouple measurements. The camera was found to be well suited to thin-filament pyrometry. The pyrometry measurements yielded gas temperatures in the range of 1350 -2200 K with an estimated uncertainty of ± 60 K, a relative temperature resolution of ± 0.215 K, a spatial resolution of 42 µm and a temporal resolution of 0.66 ms. Fiber aging had no effect on the results. Soot deposition was less problematic for the pyrometer than for the thermocouple. THIN-FILAMENT PYROMETRY WITH A DIGITAL STILL CAMERA

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confidence: 99%

Thin-filament pyrometry with a digital still camera

2007

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“…More recently, Gore and co-workers experimentally found that the mean radiation intensity is insensitive to the integral length scales, but the rms of the radiation intensity is very sensitive [27,[29][30][31]. To account for this effect, Zheng et al [29] combined the stochastic time and space series method, formerly employed by Ji et al [27] with a tomography-like procedure to determine the integral length scales from the flame edge to the axis.…”

Section: Stochastic Methodsmentioning

confidence: 99%

“…While previous works were focused on turbulent nonpremixed flames, Ji et al [27] investigated TRI in a turbulent premixed methane/air flames, and reported measurements of the mean, root mean square (rms) and pdf of spectral radiation intensities.…”

Section: Research On Turbulence/radiation Interactionmentioning

confidence: 99%

Turbulence Radiation Interaction: From Theory to Application in Numerical Simulations

Coelho

2010

2010 14th International Heat Transfer Conference, Volume 8

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Theoretical analysis and experimental investigations have shown that the mean heat fluxes in turbulent gaseous flows are influenced not only by the mean scalar fields (temperature and molar fraction of the species), but also by the scalar fluctuations. It is widely recognized that the increase of radiative fluxes in comparison with laminar flows may exceed 100%. This interaction between turbulence and radiation is mainly due to the non-linearity between radiative emission and temperature. It is particularly important in reactive flows, since temperature fluctuations are typically higher in these flows than in non-reactive ones.In this article, a survey of the theory concerning turbulence-radiation interaction (TRI) is presented, along with applications in numerical simulations. We firstly present experimental and theoretical fundamentals on TRI. Then, direct numerical simulation and stochastic methods are addressed. Although they provide reliable information on TRI, they are too computationally demanding for practical applications. We will then focus on methods based on the solution of the time-averaged form of the conservation equations. Although many different approaches are available, we will concentrate on two methods. One is based on the solution of the time-averaged form of the radiative transfer equation using the optically thin fluctuation approximation, and a combustion model based on a prescribed probability density function (pdf) approach. The second one is based on the photon Monte Carlo method for radiative transfer calculations in media represented by discrete particle fields, and a combustion model based on the Monte Carlo solution of the transport equation for the joint pdf of scalars. Finally, the role of TRI in large eddy simulation is discussed, and the main consequences of TRI in combustion systems are summarized.

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“…Resolving these interactions poses constraints on both spatial and temporal resolution, thus necessitating time-and space-resolved measurements. High repetition-rate, time-series measurements of number density, temperature, radiation and minor-species concentrations, such as for OH and CH, have been reported in jet flames [1][2][3][4][5][6], thus providing unique information regarding the effects of turbulence on the fluctuation statistics of scalars. In such flames, the integral time scale has been largely used to characterize minor species and number density fluctuations [1,2,7].…”

Section: Introductionmentioning

confidence: 99%

Time-resolved measurements of hydroxyl in stable and extinguishing partially premixed turbulent opposed-jet flames

Venkatesan

Laurendeau

Renfro

et al. 2006

Flow Turbulence Combust

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Quantitative hydroxyl time-series measurements from a set of stable and extinguishing turbulent opposed-flow partially premixed CH 4 /air flames are used to investigate the effect of Reynolds number and fuel-side equivalence ratio on the structure of turbulent partially premixed flames. The hydroxyl (OH) integral time scale, computed from the autocorrelation function, is used to characterize OH fluctuations and is found to reach a minimum at the axial location of peak OH. Analyses of the duration of and period between bursts in the OH time series are used to examine the dynamics of flame-front motion. In general, with increasing Reynolds number (Re), the distribution in OH burst times shifts towards smaller time scales. A hydroxyl intermittency parameter is also defined from the bursts to quantify the presence or absence of OH. For flames with the same fuel-side equivalence ratio, the hydroxyl intermittency at peak OH remains almost constant when going from stable to extinguishing flames. However, histograms portray an increase in burst separation times for flames displaying occasional extinction events. Hydroxyl time series for a partially premixed flame at a fuel-side equivalence ratio of 2.0 and Re = 6650 are synthesized by using mixturefraction simulations based on calculated state relationships for OH versus mixture fraction (f). The laminar-flamelet model is employed to explore relations between OH and f so as to predict trends in mixture-fraction time scales.

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Thermal radiation properties of turbulent lean premixed methane air flames

Cited by 34 publications

References 25 publications

Thin-filament pyrometry with a digital still camera

Thin-filament pyrometry with a digital still camera

Turbulence Radiation Interaction: From Theory to Application in Numerical Simulations

Time-resolved measurements of hydroxyl in stable and extinguishing partially premixed turbulent opposed-jet flames

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