• Journal of Mechanical Science and Technology
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• v.15 no.9
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• pp.1319-1327
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• 2001

The results of stand and field testing of a combustion chamber for a heavy-duty 150 MW gas turbine are discussed. The model represented one of 14 identical segments of a tubular multican combustor constructed 1:1 scale. The model experiments were executed at a lower pressure than that in a real gas turbine. Combustion efficiency, pressure loss factor, pattern factor, liner wall temperature, flame radiation, fluctuating pressure and NOx emission were measured at partial and full loads for both model and on-site testing. The comparison of these items in the stand and field test results led to has the development of a method of calculation and the improvement of gas turbine combustors.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.118.2-118.2
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• 2017

Combustion behavior of Fe, CuO, NiO, ZnO and $Fe_2O_3$ powder mixture was carried out by finite element method (FEM) to understand a reaction at iron and metal oxide interface. The FEM was done by using ANSYS Fluent 17.0. Initial and boundary conditions are 1 atmosphere, room temperature, 0.1MPa of oxygen partial pressure, $T_{S1}=1127^{\circ}C$, $T_{S2}=327^{\circ}C$ for a cylindrical shape specimen with dia. $35{\times}80$ [mm]. The maximum combustion temperature is $1537^{\circ}C$ for the condition of conduction, convection and radiation. The combustion temperature and rate are about $847^{\circ}C$ and 3.9mm/sec, respectively. The combustion wave is enough to make ternary ferrite phase like $CuNiZnFe_2O_3$.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.195-196
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• 2012

This paper describes combustion tuning methodology of double-swirl gas turbine combustor using six sigma tools. This methodology is consist of five steps-Define, Identify, Design, Optimize and Verify (DIDOV). First, the NOx reduction target was defined in the step design; second, the current status of the plant was diagnosed in the step of identify; third, the vital few control parameters to achieve the defined target were determined by analyzing the correlation between the control parameters and NOx emissions in the step of design; fourth, the optimum condition was derived from one of the six sigma tools in the step of optimize; finally, the optimum condition was verified by applying the condition to the gas turbine combustor in the step of verify. As a result of the suggested method, averaged NOx emissions were reduced by more than 70% and the standard deviation was improved by more than 60%. Thus, this methodology can be attributed to the efficient reduction of NOx emission with saving combustion tuning time.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.55-62
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• 2006

A two-step fuel-rich/fuel-lean catalytic combustion seems to be one of the most effective methods to control simultaneously the NO generation and the hydrocarbon (HC) conversion from fuel-bound nitrogen. By controlling equivalent air ratio for maintaining fuel-rich and fuel-lean condition over each catalytic layer, space velocity, inlet temperature, and catalyst component, the HCand ammonia conversion efficiency higher than 95% could be achieved, with ammonia conversion to NO remaining below 5%. The experimental results wouldbe applied to the combustion of land fill gas and to gasified refuse-derived fuels as a method of minimizing NO generation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2001.11a
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• pp.61-67
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• 2001

Hybrid propulsion systems provide many advantages in terms of stable operation and safety. However, classical hybrid rocket motors have lower fuel regression rate and combustion efficiency compared to solid propellant rocket motor. The recent research efforts are focused on the improvement of volume limitation and regression rate in the hybrid rocket engine. The present study has numerically investigated the combustion processes in the hybrid rocket engine. The turbulent combustion is represented by the eddy breakup model and Hiroyasu and Nagle and Strickland-Constable model are used for soot formation and soot oxidation. Radiative heat transfer is modeled by finite volume method. To reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect, the Low Reynolds number k-$\varepsilon$ turbulent model is employed. Based on numerical results, the detailed discussion has been made for the turbulent combustion processes in the vortex hybrid rocket engine.

• Journal of ILASS-Korea
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• v.4 no.4
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• pp.17-23
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• 1999

Recently, many researchers have been studied a D.I. diesel engine because of the exhaust gas restriction and fuel consumption performance. It is well known that the fuel injection characteristics are the key factors on the diesel combustion and exhaust emission. In this study, the fuel injection characteristics of 5-hole injector and the combustion characteristics are investigated with the amount of fuel by means of the visualization method and visualization D.I. diesel engine system. As the results of the experiments, the spray pattern of the fuel injection and the diffusion flame of a D.I. diesel engine are clarified. In addition, combustion phenomena with operation conditions such as engine speed and engine load are made clear.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.2
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• pp.9-17
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• 2002

For turbulent spray combustion flows a coupled numerical procedure was developed, This method was discretized by using generalized curvilinear coordinates to handle complex geometries. The preconditioning and eigenvalue rescaling techniques were employed to provide efficient convergences over a wide range of subsonic Mach numbers. The accuracy was validated by simulating the laminar cavity flow. The film cooling effect of a liquid rocket engine (KSR-III) were investigated by a spray combustion analysis. The film cooling showed a negative effect on the combustion efficiency. In the combustion chamber wall, the film cooling effect was revealed to be promoted by the production of fuel rich zone.

• Journal of the Korean Society of Combustion
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• v.6 no.1
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• pp.20-28
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• 2001

Self flue gas recirculation flow is an effective method for low NOx emission in a regenerative low NOx burner. The object of this study is to analyze self flue gas recirculating flow by varying the jet velocity of the combustion air. Fuel and air flow rates are fixed and combustion air jet nozzle diameters are 13, 6.5 and 5mm. The stoichiometric line is obtained from the concentration of fuel using the acetone PLIF technique. It is found that self flue gas recirculating flow is entrained into that line using the two color PIV technique. As the jet velocity of combustion air is increased, the flue gas entrainment rate into the stoichiometric line is increased. This result suggests that NOx emission can be reduced due to the effects of flue gas lowering the flame temperature.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.58-67
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• 2010

Combustion of the Korean Anthracite and wood-pellet was characterized in air atmosphere with variation of heating rate(5, 10, 20 and $30^{\circ}C/min$) in TGA. The results of TGA have shown that the combustion of the wood-pellet occurred in the temperature range of $200{\sim}620^{\circ}C$ which is much lower than that of Korean anthracite. Activation energies of the wood-pellet and Korean anthracite, determined by using Friedman method were 44.12, 21.45 kcal/mol respectively. Also, their reaction orders(n) and pre-exponential factors(A) were 5.153, 0.7453 and $4.01{\times}10^{16}$, $1.39{\times}10^6(s^{-1})$ respectively. In order to find out the combustion mechanism of the wood-pellet and Korean anthracite, twelve solidstate mechanisms defined by Coats Redfern Method were tested. The solid state combustion mechanisms of the woodpellet and Korean anthracite were found to be sigmoidal curve A3 type and a deceleration curve F1 type respectively. Also, from iso-thermal combustion($300{\sim}900^{\circ}C$) of their char, the combustion characteristics of their char was found. Activation energies of the their char were 27.5, 51.2 kcal/mol respectively. Also, pre-exponential factors(A) were $2.55{\times}10^{12}$, $1.49{\times}10^{10}(s^{-1})$ respectively. Due to the high combustion reactivity of wood-pellet compared with Korean anthracite, combustion atmosphere will be improved by co-combustion with Korean anthracite and wood-pellet.

• Journal of The Association for Neo Medicine
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• v.1 no.1
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• pp.103-113
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• 1996

It is thought that the quantity and quality of the heat stimulation and the mechanism of heating process are important to understand the moxa-combustion. In order to get the basic data on the effective moxa-combustion method, combustion temperature changes (average temperature, peak temperature, average gradient temperature and maximum gradient temperature) of the heating period were measured respectively by the density of moxa material. For the experiment, samples of $300mg/0.26cm^3$ , $400mg/0.26cm^3$ and $500mg/0.26cm^3$ of moxa material were molded in a conical mold with each 10mm in diameter and height. 1. The average temperature and peak temperature of heating period on the moxa-combustion showed higher in the $400mg/0.26cm^3$ and $300mg/0.26cm^3$ than in the $500mg/0.26cm^3$ sample respectively. 2. The average gradient temperature of heating period on the moxa-combustion rose quickly in the $300mg/0.26cm^3$, $400mg/0.26cm^3$ and $500mg/0.26cm^3$ in that order and the maximum gradient temperature rose more quickly in the $300mg/0.26cm^3$ and $400mg/0.26cm^3$ than in the $500mg/0.26cm^3$ sample respectively. According to the above results, it is concluded that the density of moxa material is (the) more important (factor) than the weight or volume of moxa material on the combustion temperature changes of the heating period for the evaluation of the quality and quantity of moxa-combustion.