• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.547-552
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• 2010

A modified VIStA (vortex inertial staged air) burner was developed and used in a once-through-type boiler. For safety, the combustion in this burner is of the non-premixed type. An air damper is installed to control the distribution of air to each combustion chamber. The effects of the air-fuel ratio and air distribution on NOx formation were investigated. The newly modified VIStA burner gives NOx reduction effect by maximum 20% in the combustion chamber of a boiler, while it yields more uniform flame than the conventional burner.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.25-31
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• 2020

Experimental investigations were conducted to examine the combustion characteristics of a swirl-stabilized double cone premixed burner nozzle used for industrial gas turbines for power generation. Several variants with different fuel injection patterns are tested to compare the combustion characteristics such as NOx and CO emissions, stability, and wall temperature distributions. Main results show that NOx emissions and stability are decreased either when the fuel hole diameter is decreased with the same number of fuel holes, or when the number of fuel holes is reduced with the same total area of fuel holes, both of which are due to a higher penetration of fuel into the air stream. Not only is NOx reduced but also stability is enhanced when the fuel hole diameter varies in an alternating manner with the same total area of fuel holes, showing that NOx reduction is due to a higher penetration of mean fuel injection path while stability enhancement is due to a lowered penetration of minimum fuel injection path.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.141-143
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• 2012

The present study is aiming at numerically analyze the soot formation processes coupled with gas reaction mechanism in turbulent non-premixed and partially premixed flames. In order to realistically represent turbulence-chemistry interactions with detailed chemical kinetics and soot formation behaviour related to the turbulent non-premixed and partially premixed flames, the transient flamelet[1] and flamelet based level-set approach[2] are coupled with soot formation based on the two equation model [3] and DQMOM (Direct Quadrature Method of Moment)[4].

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.6
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• pp.61-69
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• 2016

This study is the results related to the combustion instability phenomenon with respect to combustor length and thermal power as variables in dual swirling combustor configuration. Especially, the beating phenomena having the insensitive resonance frequency of relatively constant peaks are observed when the combustor lengths increase in a lower power regime. This beating phenomenon might be occurred due to the interacting behaviors of pilot and main burners with different periods. Therefore, such insensitive response seems to be a result of the beating phenomenon with interaction between the pilot and main flames even though the combustor lengths are increased.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.24-29
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• 1995

A laser system and signal aquisition system to use a laser-induced fluorescence technique were arranged to measure NO concentration. To identify the NO fluorescence signal, verification of the fluorescence was performed through use of comparison of the signals taken both in a undoped and doped calibration flames. Finally, the spatial NO number densities in partially premixed flames were found as a function of fuel-tube equivalence ratio(${\phi}_c$) and overall equivalence ratio(${\phi}_o$).

• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.160-167
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• 2000

We investigated a uniform temperature zone, produced by double flame structure of a coflow CH4/air partially premixed flame, to be used as a temperature calibration source for laser diagnostics. A broadband N2 CARS(coherent anti-Stokes Raman spectroscopy) system with a modeless laser was used for temperature measurement. When the stoichiometric ratio was 1.5, we found the uniform temperature zone in radial direction of the flame of which the averaged temperature was 2110 K with standard deviation 24 K. In the stoichiometric ratio range between 2.0 and 2.5, we found very stable temperature-varying zones in vertical direction at the center of the flame. The size of the zone was approximately 15 mm and it covered a temperature range from 300 K to 1900 K. We also suggest that this zone can be used as a calibration source for 2-D PLIF(planar laser induced flurescence) temperature measurement.

• 한국연소학회:학술대회논문집
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• 2002.06a
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• pp.41-45
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• 2002

The zone-conditioned CMC equations are derived by taking an unconditional average of the generic conservation equations multiplied by delta and Heaviside functions in terms of mixture fraction and reaction progress variable. The resulting equations are essentially in the same form as the single zone CMC equations except for separate flow fields for burned and unburned gas. The zone-conditioned two-fluid equations are applied to a stagnating turbulent premixed flame brush of Cheng and Shepherd[5l. It is shown that the flame stretch factor is of crucial importance to accurately reproduce the measured mean reaction progress variable and conditional velocities. Further work is in progress for the relationship between surface and volume averages and extension to partially premixed combustion on the basis of a triple flame structure, e. g. in a lifted turbulent diffusion flame.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.123-125
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• 2012

In this study, combustion characteristics for 20t/h water tube boilers are studied. The burner by applying The fuel staging technology, the air staging technology, the partially premixed technology, the separated flame technology and the flame inner recirculation technology was designed. This study was to determine the combustion characteristics for the three types of burners. It is found that the result of flame temperature measurement is less than $1300^{\circ}C$ at the all flame region. also, emissions of NOx and CO are found to be 15.8 ppm and 18.9 ppm, respectively.

• Journal of the Korean Society of Combustion
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• v.22 no.1
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• pp.23-31
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• 2017

Large-scale fuel tanks emit massive amount of hardly-combustible VOC mixtures which are light hydrocarbon species in dilution with nitrogen and carbon dioxide. We have developed a lab-scale burner to combust those VOC mixtures by use of a turbulent partially-premixed flame as a pilot flame. For a higher HC treatment ratio, the mixture gases were reformed by a rotating arc plasma device. The results showed that the nitrogen mole fraction and the injecting speed of the VOC mixture influence on the performance of the burner. It was also found that the size of the pilot flame and the power supplied to the plasma device determine the overall HC treatment ratio and the concentrations of CO and NOx in the exhaust gas.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.193-196
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• 2015

Combustion of low concentration VOC in inert gas around the flammability limit has been experimentally studied. Streams of nitrogen and propane mixture with various compositions and flow conditions were treated by a turbulent partially-premixed pilot flame. HC and CO contents in exhaust gas measured and the flow patterns were visualized. The results suggested that there exists an optimal mixture velocity range for efficient combustion treatment for each flow condition and composition of the mixture.