• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.373-376
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• 2009

A full rig combustor test and altitude ignition test were carried out for radial-annular combustor of micro turbojet engine. 11.2% total pressure loss and 99.85% of combustion efficiency were measured at design point of engine under sea level standard condition and $2{\sim}6$ of air excess ratio for ignition envelope was achieved on engine starting regime. Finally, A 30,000 ft high altitude ignition test was also performed and finally we found out that the developed radial-annular combustor is appropriate to micro turbojet engine.

• Journal of Mechanical Science and Technology
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• v.18 no.3
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• pp.499-512
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• 2004

The effects of swirl intensity on non-reacting and reacting flow characteristics in a flat flame burner (FFB) with four types of swirlers were investigated. Experiments using the PIV method were conducted for several flow conditions with four swirl numbers of 0, 0.26, 0.6 and 1.24 in non-reacting flow. The results show that the strong swirling flow causes a recirculation, which has the toroidal structures, and spreads above the burner exit plane. Reacting flow characteristics such as temperature and the NO concentrations were also investigated in comparison with non-reacting flow characteristics. The mean flame temperature was measured as the function of radial distance, and the results show that the strong swirl intensity causes the mean temperature distributions to be uniform. However the mean temperature distributions at the swirl number of 0 show the typical distribution of long flames. NO concentration measurements show that the central toroidal recirculation zone caused by the strong swirl intensity results in much greater reduction in NO emissions, compared to the non-swirl condition. For classification into the flame structure interiorly, the turbulence Reynolds number and the Damkohler number have been examined at each condition. The interrelation between reacting and non-reacting flows shows that flame structures with swirl intensity belong to a wrinkled laminar-flame regime.

• World Technopolis Review
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• v.3 no.3
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• pp.139-152
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• 2014

The current transportation regime is largely based on two alternatives: (1) fixed route public transit, and (2) private ownership of internal combustion engine (ICE) powered vehicles per households. This paper analyzes one possible transportation alternative, Micro Electric Vehicles or MEVs, and compares with the ICE vehicles in terms of social, economic and environmental benefits, especially emphasizing its environmental advantage over ICE vehicles for future sustainability. While some representative models of MEVs exist in a limited market capacity, but global technical standards are generally insufficient and non-homogenous across nations, which restricts the development of the proposed transportation sector. The focus of this paper is to analyze the characteristics and potential benefits of MEVs in economical and environmental perspectives, including development status and technical standards, with a particular focus in the E.U., the U.S., Japan, and Korea. Based on the data of analysis, this paper aims to derive and propose a cooperative and adaptive global policy framework designed to speed up adoption and expansion of the global MEV market, including passenger and utility vehicles. We propose MEV to be a new mobility segment in the global transportation market because of their advantage in environmental impact, sustainability, overall cost of ownership, and safety.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.3
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• pp.10-16
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• 2004

Untypical unstable burning with very low frequency was observed at firing test of a gas generator using bundle cylindrical grain. The pressure unbalance between inside and outside of cylindrical grain brought such a low unstable burning. The grains were radially holed so that the high pressure gas inside of grain could quickly moved outward of gain, resulting dissipation of the pressure unbalance However too many holes were required to let the burning be stable for all operation regime from low to high temperature of grain and resultantly deteriorate the Progressive increase of gas amount produced by a gas generator. So another idea using grids located both sides of a bundle grain was applied to dissipate actively large vorticities enhanced by unbalance pressure distribution in a combustor. Finally stable burning with progressively increase of gas was established by application of 5${\times}$5 grid slightly away bundle grain to move bundle gain freely in case pressure unbalance were occurred inside of combustor.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.735-742
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• 2011

A catalytic burner that utilizes the thermal energy from fossil fuels without the emission of nitrogen oxides ($NO_x$) has been developed. For this purpose, the newly developed burner has two features: firstly, it is in the shape of a flat mat so as to maximize its heating surface, and secondly, it adopts premixed combustion so that it can be used in a closed space. In the present study, the burner was used in a radiation-type industrial dryer. This dryer yields thermal energy in the form of thermal radiation in the infrared regime, which has been proved to be effective for drying organic substances under low-moisture conditions. Analysis of the experimental data has proved that the thermal efficiency of the dryer is better correlated to the moisture than to the dry rate

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.204-210
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• 2016

This paper presents an experimental analysis of the growth and oxidation processes of soot particles generated in an isooctane diffusive laminar flame due to incomplete combustion. The effects of iron-based diagnostics were employed to measure the elastic scattering light from soot particles in a flame at different flame heights, and the differential scattering coefficients were calculated through a calibration process. The growth and oxidation of soot particles in flame was investigated by comparing differential scattering coefficients, and the soot volume fraction was seen to decrease in the soot oxidation process. In the same manner, the differential scattering coefficients were calculated for iron-based fuel-additive seeded flame, and these coefficients were revealed to be smaller than those obtained in the fuel-additive unseeded flame. In addition, transmission through the radial direction of the flame was measured, and transmission in the soot oxidation regime was approximately 5% higher for the seeded flame. The propensity of the data coincided well with the differential scattering coefficients, and it can be concluded that the iron component of the fuel additive plays a crucial role as a catalyst, which eventually enhanced soot particle oxidation.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.26-32
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• 2001

Influence of various rates of fractionated raw cow manure on hydraulic conductivity of the soil was observed. The fractionated raw cow manure(hereafter as FRCM) incorporated into soil. The hydraulic conductivity was measured for the double-layered soil while maintaining the water head by 5 cm over the soil surface. The influence on the mobility of $NO_3{^-}$-N transformed from the FRCM was analyzed. The upper layers (Wolgok series) were made with FRCM ranging from 0% to 10.4 % on weight basis for air-dried soil while the organic matter in the bottom layers (Chungwon series) was removed by combustion. The initial bulk densities for both layers were adjusted to $1.25g\;cm^{-3}$. In this experiment the $K_{sat}$ for the upper layer gradually decreased from $4.71{\times}10^{-3}cm\;min^{-1}$ to $1.2{\times}10^{-3}cm\;min^{-1}$ with increasing the rate of the FRCM from 0 % to 10.4%, while the Ksat of the bottom layer was maintained as $3.7cm\;min^{-1}$. For the double-layered soil columns, the $K_{sat}$ decreased with increasing rate of FRCM at the upper layer from $1.7{\times}10^{-3}cm\;min^{-1}$ to $8{\times}10^{-4}cm\;min^{-1}$ as the rate of organic matter increased from 0 % to 10.4 %, while it took almost 7 days to 64 days to obtain the steady state $K_{sat}$ The elution patterns of $NO_3{^-}$-N and $NH_4{^+}$-N showed that the amounts of both $NO_3{^-}$-N and $NH_4{^+}$-N rapidly approached to the maximum ranging from $14.8mmol_c\;kg^{-1}$ to $0.58mmol_c\;kg^{-1}$ as the rate of FRCM decreased from 10.7 % to 0 % which is equivalent to indigenous amount of $NO_3{^-}$-N and $NH_4{^+}$-N. And the amounts of $NO_3{^-}$-N were approximately three or four time than those of $NH_4{^+}$-N, indicating that the transformation rate of $NO_3{^-}$-N was improved by the higher FRCM rate. Thus, the ability of a soil to supply N can be predicted from its mineralization parameters and leaching potentials influenced by water flow regime in soil.