Optical diagnostics of fuel–air mixing and vortex formation in a cavity combustor

Krishna, S.; Ravikrishna, RV

doi:10.1016/j.expthermflusci.2014.10.012

Cited by 31 publications

(13 citation statements)

References 11 publications

(7 reference statements)

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“…Earlier works have reported that the TVC concept aids in obtaining low pollutant emissions, with ultra-low NOx particularly [1][2][3][4][5]. One of our previous works reported the cavity structures measured using acetone PLIF and PIV techniques in a single cavity TVC by defining a parameter namely the momentum flux ratio (MFR) [6]. A clear trend based on the MFR was observed and the same has been established with sufficient rigor.…”

Section: Introductionmentioning

confidence: 84%

“…This section discusses the results of numerical simulations carried out using RANS and LES framework and the comparison of these results with previous experiments [6,7]. Insights are also obtained from the simulations to explain the results of the exhaust measurements reported in the next section.…”

Section: Numerical Studies: Rans and Les Simulationsmentioning

confidence: 89%

“…where vcf is the cavity fuel jet velocity (m/s), vgv is the guide vane air stream velocity (m/s), ρf is the density of the fuel stream (kg/m 3 )and ρgv is the density of the guide vane stream (kg/m 3 ). The MFR has been found to be the controlling parameter for mixing and resultant combustion in our previous studies [6,7]. Syngas used in this study has a composition of CO-20%, H2-20%, CO2-12%, CH4-2% and the rest N2, with a LHV of ~5MJ/kg.…”

Section: Accepted Manuscript N O T C O P Y E D I T E Dmentioning

confidence: 91%

“…It can be seen that simulations and experiments show similar OH contours in terms of location of the peak OH concentration. Previous studies [6,7]…”

Section: Reacting Flow Simulations: Oh Concentration Profilesmentioning

confidence: 99%

“…Simulation conditions have been chosen to include high to low MFRs corresponding to experimental measurements[6,7] of mixture fraction, velocity field under non-reacting conditions and OH concentration and velocity field under reacting conditions. The results of simulations are presented in the form of profiles along the sections shown inFig.…”

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confidence: 99%

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Numerical and Experimental Studies on a Syngas-Fired Ultra Low NOx Combustor

Krishna

Ravikrishna

2017

Journal of Engineering for Gas Turbines and Power

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Simulations and exhaust measurements of temperature and pollutants in a syngas-fired model trapped vortex combustor for stationary power generation applications are reported. Numerical simulations employing Reynolds-averaged Navier–Stokes (RANS) and large eddy simulations (LES) with presumed probability distribution function (PPDF) model were also carried out. Mixture fraction profiles in the trapped vortex combustor (TVC) cavity for nonreacting conditions show that LES simulations are able to capture the mean mixing field better than the RANS-based approach. This is attributed to the prediction of the jet decay rate and is reflected on the mean velocity magnitude fields, which reinforce this observation at different sections in the cavity. Both RANS and LES simulations show close agreement with the experimentally measured OH concentration; however, the RANS approach does not perform satisfactorily in capturing the trend of velocity magnitude. LES simulations satisfactorily capture the trend observed in exhaust measurements which is primarily attributed to the flame stabilization mechanism. In the exhaust measurements, mixing enhancement struts were employed, and their effect was evaluated. The exhaust temperature pattern factor was found to be poor for baseline cases, but improved with the introduction of struts. NO emissions were steadily below 3 ppm across various flow conditions, whereas CO emissions tended to increase with increasing momentum flux ratios (MFRs) and mainstream fuel addition. Combustion efficiencies ∼96% were observed for all conditions. The performance characteristics were found to be favorable at higher MFRs with low pattern factors and high combustion efficiencies.

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Section: Introductionmentioning

confidence: 84%

Section: Numerical Studies: Rans and Les Simulationsmentioning

confidence: 89%

Section: Accepted Manuscript N O T C O P Y E D I T E Dmentioning

confidence: 91%

“…It can be seen that simulations and experiments show similar OH contours in terms of location of the peak OH concentration. Previous studies [6,7]…”

Section: Reacting Flow Simulations: Oh Concentration Profilesmentioning

confidence: 99%

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confidence: 99%

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