Mixing Enhancement in a Compact Trapped Vortex Combustor

Agarwal, Krishna Kant; Krishna, S.; Ravikrishna, RV

doi:10.1080/00102202.2012.721034

Cited by 55 publications

(17 citation statements)

References 10 publications

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“…This situation is not remedied even by the introduction of the struts, which in spite of improving the pattern factor, does not ensure complete combustion of the excess fuel added in the mainstream. This is consistent with observations made by Agarwal and Ravikrishna [5], that struts improve the mixing of the mainstream and the products from the cavity which is reflected on the pattern factor improvement. In addition, the increase in THC levels is confirmed by the 12 ppm THC levels in the case of MFR 4.5 with struts and no premixing (not shown here).…”

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

confidence: 93%

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

confidence: 93%

“…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].…”

Section: Introductionmentioning

confidence: 99%

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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“…It is interesting to note that for all the cases considered in the present investigation, the NO x emission level is less than 2.6 ppm at 15% O 2 . Similar order of NO x emission level is reported in a single cavity TVC by Agarwal et al, 9 where the cavity-mainstream interactions are enhanced by using passive devices such as struts. However, in the present investigations, interactions between cavity and mainstream are enhanced mainly by varying the primary air velocity and hence the interactions can be controlled as required.…”

Section: Exhaust Emission Level For Premixed Mainstream Casesupporting

confidence: 80%

Experimental investigation on the performance characteristics of a 2D trapped vortex combustor

Kumar

Mishra

2016

Proceedings of the Institution of Mechanical Engineers, Part G:

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The performance characteristics of a 2D trapped vortex combustor (TVC) are investigated experimentally in terms of the exhaust gas emission level, combustion efficiency, and the exit temperature uniformity. The present study reveals that the EICO and EIUHC emission levels are sensitive to mainstream Reynolds number ( Rems), cavity equivalence ratio ( Øc), and primary air velocity ( Vp). Besides this, mainstream premixing also has significant impact on the emitted pollutant level. Moreover, the NOx emission level can be reduced to very low levels (<2.6 ppm), which will be difficult to achieve in conventional combustors. Combustion efficiency calculated from these emission results indicates that it is influenced by cavity equivalence ratio and primary air velocity. For particular Rems, Vp, and Øc, combustion efficiency closer to 99% could be achieved for the merged flame cases, especially at higher primary air velocity. On the other hand, for a particular value of Vp, an increase in Rems tends to quench the cavity flame leading to reduction in combustion efficiency. This study also indicates that flame merging helps in efficient utilization of fuel and thus leading to better combustion efficiency. Besides this, the conditions for achieving lower pattern factor ( PF) are also brought out from exit temperature measurements. Pattern factor as low as 0.1 could be achieved particularly at higher Vp cases. It can be noted that this value is lower than that of the PF value of swirl combustors (0.2–0.4). Based on the present investigations, it can be concluded that TVC is a viable technology to be considered for future gas turbine application.

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“…However, in a high-power state, the combustor must supply fuel for the cavity zone and the mainstream zone simultaneously. Through reasonable staged combustion, the vortex combustor can perform well [1,4,6]. Previous studies show that the vortex combustor is a compact structure with a low lean blowout * Corresponding author.…”

Section: Introductionmentioning

confidence: 99%