• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.61-61
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• 1999

• Clean Technology
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• v.26 no.3
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• pp.211-220
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• 2020

This experimental study investigates the design parameters to achieve ultra low NOx combustion of coal using a 80 kW capacity single-burner furnace. The influence of key design parameters such as SN, overall and burner-zone equivalence ratios, primary/secondary air ratio, overfire air (OFA) ratio were tested for a total of 81 cases. The results showed that weak swirl intensity of the burner leads to higher NOx emission whereas strong swirl intensity accompanies increased CO concentration desipte lower NOx emission. Therefore, finding an appropirate swirl intensity is essential for the burner design. Larger flow rate of secondary air increased NOx emission, whereas smaller flow rate stretches the flame and increased CO emission. The lowest NOx emission of 82 ppm (6% O₂) was achieved at the optimal condition of the present burner deisgn. It is expected to furrther lower the NOx emission by introducing splitting the burner secondary air into three or four streams.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.139-143
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• 2005

Combustion Test Facility for Liquid Rocket Engine using kerosene and liquid oxygen has been developed for the purpose of cooling and performance study. Test engine of thrust 0.5 KN(design thrust) is tested to confirm the normal operation. Therefore, water-cooled firing tests using kerosene engine with injectors of fuel-centered coaxial type are conducted. With the viewpoint of characteristic velocity, and specific impulse at sea level, and chamber pressure on OF mixture ratio are analyzed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.2
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• pp.91-97
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• 2002

Dynamic extinction of solid propellants subjected to rapid pressure drop was studied with the aid of energy equation of condensed phase and flame model in gas phase. It is found that the total residence time($\tau_\gamma$) which measures the residing time of fuel in the reaction zone may play a crucial role in determining the dynamic response of the combustuion to extinction. Residence time was modeled by various combinations of diffusion and chemocal kinetic time scale. Effect of pressure history coupled with chamber volume on the extinction response was also performed and was found that dynamic extinction is more susceptible in a confined chamber than in open geometry. And, dynamic extinction was revealed to be affected profoundly by diffysion time scale rather than chemical kinetic time scale.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.2
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• pp.9-17
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• 2017

Dynamic mode decomposition (DMD) method was applied for the further study of periodical characteristics of the unsteady shock-induced combustion. The case of Lehr's experiments was numerically simulated using 4 levels of grids. FFT result reveals that almost all the grid systems oscillate at frequencies around 430-435 kHz and the measureed one is around 425 kHz. To identify more resonant modes with low frequencies, DMD method is adopted for 4 grid systems. Several major frequencies are extracted and their damping coefficients are calculated at the same time, which is a quantification parameter for combustion stabilization.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.3
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• pp.9-17
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• 2002

This Study is to investigate 8 composite propellants including Butacene and ${Bi_2}{O_3}$ by Shotgun/RQ Bomb test. Burning rate and mechanical properity are known to be major factors in determining the deflagrability of propellant. Propellant including over 5.5% Butacene(Ferrocene grafted HTPB) burned out over 135 m/s of impact velocity during Shotgun/RQ Bomb test. It was blown that Butacene was very sensitive material under high velocity impact. In the test results, propellants under 25mm/s in burning rate at 1500 psia could meet the requirements for IM of UN Test Series 7c(ii). Propellant deflagrabillity depends on burning rate at performance in the results of the present.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.198-204
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• 2004

Using liquefied natural gas as a fuel, water, natural gas and liquefied natural gas-cooled firing tests were conducted. With the viewpoint of characteristic velocity, and specific impulse, the effect of OF mixture ratio and fuel inlet temperature into a combustion chamber were analyzed. OF mixture ratio and fuel inlet temperature into a combustion chamber have great influence on the performance. Characteristic velocity and theoretical specific impulse attain the maximum value at 0.72~0.75 and 0.75 of OF mixture ratio, respectively. Engine performance has a tendency to increase, proportional to fuel inlet temperature into a combustion chamber affected by the regenerative cooling.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.341-350
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• 2011

A simplified analytical study for micro-sized single metal particle combustion in air was conducted in the present study. The metal particle combustion consists of two distinct reaction regimes, ignition and quasi-steady burning, and the thermo-fluidic phenomena in each stage are formulated by virtue of the conservation and transport equations. When particle temperature reaches to 1200 K, ended an ignition stage and was converted at quasi-steady combustion stage. Effects of Initial particle size, convection, ambient pressure and temperature are examined and addressed with validation.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.1
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• pp.54-60
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• 2004

Experimental study on combustion characteristics of double swirl coaxial injectors has been conducted for the assessment of critical injector design parameters. A reusable, subscale thrust chamber has been fabricated with a water-cooled copper nozzle. Two different configurations of injectors have been tested for the understanding of the effects of recess length on high pressure combustion. Clearly, the recess length drastically affects the combustion efficiency and hydraulic characteristics of an injector. Internal mixing of propellants in an injector with recess number of two increases a combustion efficiency and reveals sound combustion although a pressure drop required for the same amount of mass flow rates increases compared with an injector of recess number of one.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.5
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• pp.51-59
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• 2007

The end-burning combustion field using impinging oxidizer injectors are analyzed with tangential type injectors in order to examine their mixing and combustion characteristics. The impinging type showed further improved mixing effect as well as the combustion efficiency compared to the previously studied tangential injector. A novel injector capable of delivering impinging and swirl effect is introduced in this study where it demonstrated that the grain coning effect can be avoided. It was found that the combined impinging and swirling flow would promote the radial mixing rate increasing the residence time and the turbulent intensity. However, the use of the step combustor which may augment the turbulent intensity did not show any notable difference compared to the basic combustor.