• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.39-44
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• 2010

Economic feasibility of power generation system using waste woody biomass in a circulating fluidized bed combustor has been investigated. Effects of important variables such as capital investment, cost of waste wood, certified emission reduction(CER), system marginal price(SMP) on the benefit of business have been analyzed. Internal rate of return(IRR) was predicted as 16.67%, which implicates the business is promising based on the assumptions such as SMP of 99 Won/kWh, capital cost of 10.65 billion won, and complimentary providing of waste wood. Major factors affecting the benefit of business were as follows; system marginal price, operational rate, capital investment, expenditure of waste wood, certified emission reduction. In addition, it must be necessary to consider CHP power plant providing steam as one of the means to diversify sales network, for the management of the business risk.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.2
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• pp.74-80
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• 2008

The feasibility study into the development of turbine spinners, which start up the turbo-pump, has been carried out and the design requirements and parameters ranges have been presented. Turbine spinners use the solid propellant as such composite propellant based AN compound with high energy plasticizers, coolants, and phase stabilizer which relieves a sensible volume change due to the phase transformation of AN near room temperature. Propellants which have a homing rate of $0.2{\sim}0.3\;mm/s$ and pressure exponent ranged from 0.3 to 0.6, showed stable burn-out in the standard motor tests. Both the magnitude of ignition energy and its thermal transfer mechanism have been proved to have a tangible effect on the ignition of the pyre starter, and the results of this study showed that a flame temperature of 1400K would be quite adequate to get a stable ignition for the AN composite propellant.

• Fire Science and Engineering
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• v.24 no.6
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• pp.28-33
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• 2010

The present study develops a numerical model based on the computational fluid dynamics technique to analyse the thermal flow characteristics of large scale fire calorimeter and examine the characteristics of primary parameters affecting on the uncertainty of heat release rate measurement. ANSYS CFX version 12.1 which is a commercial CFD package is used to solve the governing equations of the thermal flow field and the eddy dissipation combustion model and P-1 radiation model are applied to simulate the fire driven flow. The numerical results shows that the horizontal duct system with $90^{\circ}$ bend duct was shown relatively high deviated asymmetric flow profiles at the sampling location and the deviation of the velocity field was higher than that of the temperature and species quantities. The present study shows that the computational model can be applicable to optimize the design process and operating condition of the large scale fire calorimeter based on the understanding of the detail flow field.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.961-967
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• 2011

The objective of this study was to develop a new method for estimating gas interchangeability for 13A gas appliances. The three basic principles for the development of this method are as follows: 1) to derive the secondary interchangeability factor that represents the effect of gas composition, in addition to the major interchangeability factor, i.e., Wobbe index; 2) to test every type of and each maker's domestic gas appliances that are widely used in our country, particularly including premixed gas appliances; and 3) to develop a simple estimation method. On the basis of these principles, thirty representative gas appliances were tested, and as a result, a simple two-dimensional interchangeability diagram consisting of Wobbe index and relative density was developed. Unlike conventional methods for estimating interchangeability, this method can be applied to premixed gas appliances, which have a narrow stable flame range, and the interchangeability range of this method then becomes narrower than that of the conventional methods.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.40-45
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• 2018

The propellant tile and crack which account for the greatest proportion of solid rockets are profoundly affected by viscosity and mechanical properties of solid propellant. In this paper solid propellant with nitrate ester polyester(NEPE) system has been researched for the viscosity, mechanical properties and burning properties with size and mixing ratio of RDX. the viscosity of propellant was changed significantly depending on the size of RDX and mixing ratio, and mechanical properties of NEPE system propellant were also varied. Considering both lower viscosity and stable mechanical properties, the optimum size and mixing ratio of RDX can be identified as the main factors to the NEPE system propellant.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.127-133
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• 2020

The international cancer research institute under the WHO designated fine dust as a first-class carcinogen. Particular matter refers to dust that is small enough to be invisible and floating in the air. Particular matter is mainly emitted from the combustion process of fossil fuels such as coal and oil, and is a risk factor that can cause lung disease, pneumonia, and heart disease. The Ministry of Environment recently analyzed the output data of 10 fine dust measuring stations and, as a result, announced that about 60% had an error that the existing atmospheric measurement concentration was higher. In order to accurately predict fine dust, the wind direction and measurement position must be corrected. In this paper, in order to solve these problems, fuzzy rules are used to solve these problems. In addition, in order to calculate the fine particulate sensation index actually felt by pedestrians on the street, a computer simulation experiment was conducted to calculate the fine particulate sensation index in consideration of weather conditions, temperature conditions, humidity conditions, and wind conditions.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.4
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• pp.57-66
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• 2001

The precise prediction of the performance is essential to develope the system at the development of propulsion system since no experimental data are available. The accuracy of 1on the total system's performance as well as itself, which depends on how the correction fac $I_{sp}$, and so on, are determined in accurate. However some of the design factors are dete engineer's experience or the similar test data if they are available, so far. This study was the method of the determination of correction factors of both $I_{sp}$ and thrust in direct. The bas is to define the detail performance loss mechanism of solid rocket motors, might be occurre and to calculate in quantitative those correction factors from the performance loss mechanism the test results, the model of this study can predict those factors less than 1% error, in additi physical variances of each loss mechanism.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.965-973
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• 1992

Boilers, which are considered to be one of the basic equipment in industry, consume large potion of nation's petroleum and their demand is growing everyday. In recent, the technology improvement in production of high efficiency boilers and their effective utilization is needed for design of boiler which steam condition is the large capacity of high temperature and high pressure. It is necessary that boiler control system be studied for high efficiency, high reliability and smooth operation. The control of drum pressure and water level particularly becomes an important task for greater accuracy with the avail ability of boiler operation. To achieve this aim, dynamic analysis of a boiler is accomplished by choosing a boiler as a model. Transfer function thus obtained is made a comparison of measurement with reckoning to technical design data. The results of comparison makes it possible to verify thermodynamical analysis on the dynamic behavior of the overall system.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.22-27
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• 2013

HCNG engine is performed as a future engine because of high combustion efficiency and eco-friendly property, and is predicted to a brdge of hydrogen vehicles. As EURO-6 regulagion is due to be applied in 2014, consolidated regulations of methane gas that is exhausted from CNG and HCNG vehicles will come into effect. In this studies, methane oxidation catalyst is introduced to remove methane gas from HCNG emissions. Methane oxidation efficiency on catalyst was studied when it is driven long time. And characterization like metal dispersion, surface area was performed to investigate the correlation of catalyst efficiency and characteristics.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.9
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• pp.759-769
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• 2021

For aerospace propulsion systems, Titanium Hydride Potassium Perchlorate (THPP) is a material commonly used as a pyrotechnic initiator that generates gas when energy is supplied or as a supplement charge for NASA standard initiator (NSI). However, when the energetic materials are stored for a long time, it faces the problem of 'aging'. In this study, changes in thermodynamic properties of THPP aged under various humidity environments were identified through thermal analysis and surface analysis. First, a considerable amount of cracks on the surface of the oxidant was found in the aged THPPs. Particularly, when the humidity level increased, the number and length of the cracks rapidly increased. Also, the deterioration of Viton was found only in the thermally aged sample whereas the oxidation of the fuel was more pronounced in the hygrothermally aged samples. The extracted kinetic parameters of THPP on the reaction progress vary greatly by the humidity level, indicating that moisture significantly changes the performance and combustion reaction of THPP, which may eventually result in a reduced lifespan.