• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.799-801
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• 2002

To develop GIS (Gas Insulated Switchgear), prediction of the flow field including pressure in GIS is very important. The transport phenomena in GIS including arc is also being studied in these days. In this study, to predict the arc behaviour for GIS with voltage rating up to 800kV developed by HHI (Hyundai Heavy Industries Co. Ltd.), the analysis of flow and electric field in GIS were investigated. To simulate the compressible flow in GIS, the CFX, commercial CFD code, was used. The movement of the piston and the electrode of the GIS was simulated with moving grid method, which was superior to the method of varying the property of cells in the aspect of accuracy and convergence of solution. The calculated maximum pressure within the puffer cylinder was matched with experimental data within 5% error. Also, the oscillation of pressure in GIS after the movement of electrode was well predicted.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.676-684
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• 2012

Numerical analysis was performed to investigate the heavy-weight impact noise of apartment houses. The FEM is practical method for prediction of low-frequency indoor noise. The results of numerical analysis, the shape of the acoustic modes in room-2 are similar to that of acoustic pressure field at the fundamental frequency of acoustic modes. And the acoustic pressure was amplified at the natural frequency of the acoustic modes and structural modes. The numerical analysis result of sound pressure level at 63 Hz and 125 Hz octave-band center frequency are similar to the test results, but at 250 Hz and 500 Hz have some errors. Considering most of bang-machine force spectrum exists below 100 Hz, the noise at 250 Hz and 500 Hz are not important for heavy-weight impact noise. Thus, the FEM numerical analysis method for heavy-weight impact noise can apply to estimate heavy-weight impact noise for various building systems.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.341-344
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• 2006

In this analytical study on the engine coolant flow of a heavy-duty diesel engine with 4 valves and linear-type 8 liter 6 cylinders, the characteristics of pressure drop and engine cooling performance with the additional coolant passages between cylinder blocks have been investigated. Since the most part of pressure drop is caused by the coolant flow passages inside a cylinder head and cylinder blocks for this type of heavy-duty diesel engines, the advantage of pressure drop is just 2.6% and the characteristics of heat transfer and the distribution of coolant velocities in the head part show little differences in case of additional coolant passages. Thus the coolant flow passages between cylinder blocks make little contribution on the cooling performance of heavy-duty diesel engines

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.394-402
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• 2009

To investigate the heavy-weight impact noise of apartment houses, numerical analysis was performed. The analysis acoustic pressure consider acoustic mode by finite element method. The variables considered effecting on the acoustic pressure are the Acoustic mode, acoustic damping, and the impulse load. The heavy-weight impact noise is a changeable value in the room. Since the most part of the frequency component of heavy-weight impact noise has low frequency. The noise in low frequency is related to the vibration of structure, the reflection of acoustic wave caused by wall and the standing wave called by acoustic mode. The prediction by the numerical analysis was verified with test result of the heavy weight-impact noise at apartment houses.

• Journal of ILASS-Korea
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• v.20 no.3
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• pp.195-201
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• 2015

This study discusses a fuel injector test bench containing a mechanical type fuel supply system for heavy duty diesel engine. The main focus of this study was to evaluate the design stability of the test bench, which basically measures the injector durability of a multi-hole heavy duty injector by using pure diesel as a test fuel. In this experiment, diesel spray was controlled by a specially designed control box and all the experiments were carried out to measure e.g. fuel injection pressure and fuel injection quantity to understand the injection status which is interlinked with the stability factor of total test bench design. Also, the durability test was performed to understand the heavy duty operation lastingness of the designed system and the flow rate of the installed distributor pump in the fuel supply system of this studying test bench was compared with LO-1 and LO-2 pump. The results of the above mention tests revealed that the injector test bench design and control system can serve the purpose for heavy duty injector.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.2
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• pp.243-249
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• 2010

The improvement of fuel economy and the reduction of diesel exhaust PM(Particulate Matter) and $NO_X$ have been successfully achieved by supplying diesel engines with emulsified diesel oil. However, combustion analysis of emulsified C-heavy oil is difficult because the combustion characteristics of emulsified C-heavy oil compared to other fuels have a special form. Therefore, these experimental researches have analyzed the combustion characteristics of emulsified C-heavy oil in a chamber with high pressure and temperature. The pressure and the rate of heat releases in a combustion chamber was decreased with increasing the water content and the ignition delay time was increased with increasing the water percent.

• Progress in Superconductivity
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• v.14 no.1
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• pp.17-23
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• 2012

The heavy-fermion compound $CeRhIn_5$ is a prototypical antiferromagnet where Ce 4f moments align antiferromagnetically below 3.8 K. When doped with Hg, the antiferromagnetic transition $T_N$ initially decreases, becomes flat, and increases again with further increasing Hg concentration. Here we report pressure effects on the electrical resistivity of a 0.45 % Hg-doped $CeRhIn_5$, where $T_N$ is 3.4 K and the magnetic structure is same as that of the undoped compound with Q=(1/2, 1/2, 0.298). With increasing pressure, $T_N$ is suppressed and a superconducting state emerges. The temperature dependence of the electrical resistivity near an optimal pressure shows a power-law behavior that deviates from a $T^2$ dependence, indicating presence of abundant quantum fluctuations near the optimal pressure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.97-102
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• 2004

The Characteristics of noise and vibration by heavy-weight floor impact sound was studied. Resonance frequency increased a little in structures that use damping material in living room and bedroom, and acceleration waves length that respond became short, and displayed aspect that oscillation level decreases. Result that measure sound pressure level, structure that compare and applies damping materials with structure that apply the resilient materials from 63Hz lower part that impact energy is concentrated in energy spectrum of heavy-weight floor impact sound displayed result that sound pressure, level decreases remarkably. Therefore, according to use of damping materials, confirmed reduction effect of heavy-weight floor impact sound.

• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.107-114
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• 1999

To find the best combustion conditions in the heavy oil burner kinetic viscosity of heavy oil A, B and C at different temperature range, from 40 to 140$^{\circ}C$, and the droplet sizes of the heavy oils at different temperature and pump pressure were measured. And, combustion characteristics were investigated under the different conditions : two different heavy oil and three different oil temperature. At temperature of 70, 100, 130$^{\circ}C$ the kinetic viscosity of heavy oil A and B are 7.9, 5.7, 4.3 and 30.4, 13.7, 7.9cSt, respectively. The greatest and smallest viscosity were 7,455 cSt at C oil on 27$^{\circ}C$ and 4.26cSt at A oil on 140$^{\circ}C$. The magnitude of viscosity difference between at 100$^{\circ}C$ and 140$^{\circ}C$ under 6 cSt in cases of A and B oil, but more than 30cST on C oil. Of the droplet sizes, the biggest and smallest droplet size in A oil were 98$\mu\textrm{m}$ at oil temperature of 130$^{\circ}C$(4.3cSt), pump pressure of 1.57MPa and 72$\mu\textrm{m}$ at 70$^{\circ}C$(7.9cSt), 2.35MPa, respectively. It appeared that as spraying pressure increased the droplet size decreased, however, no distinct differences were found in the effects of kinetic viscosity on the droplet sizes of the test range. The best combustion performance was observed when droplet size, spraying pressure and oil temperature were 73$\mu\textrm{m}$, 2.35MPa and 70$^{\circ}C$ producing CO2 of 13.1%, CO of 13ppm and flue gas temperature of 250$^{\circ}C$ in A oil combustion For B oil, it was100$^{\circ}C$, 2.35MPa, 52$\mu\textrm{m}$, producing CO2 of 10ppm and flue gas temperature of 260$^{\circ}C$. In general, it appeared that better combustion results were observed in the smaller droplets produced burner condition.

• Journal of Integrative Natural Science
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• v.1 no.2
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• pp.89-114
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• 2008

Interrelationship between heavy rainfalls and related with low-level jets(LLJ) is analyzed by using fifty cases of heavy rainfall events occurred over the Korean peninsula from 1992 to 2001. Those cases are classified with four synoptical features. There are 32% chances that the low pressure exist in heavy rainfall over than 150 mm per day case by case. Secondly Changma front and front zone account for 28% of all cases. The ratio of marine tropical boundary type and trough type record 22% and 18% respectively. The moist and warm south-westerly winds associated with low-level jets have been induced convective instability and baroclinic instability. Therefore, heavy rainfall due to the approach of a low pressure occurred at September and before Changma. During the period of Changma, this type has been happened heavy rainfall when low pressure and stationary front has vibrated south and north. Changma type has longer the duration time of precipitation than other types. Third type, located with marine Tropical boundary, have mainly rained in August and September. The last trough case locally downpoured in short time with developing cell. The occurrence low-level jets related to heavy rainfall has increased over 12.5 m/s wind speed. The result is that 43 heavy rainfalls out of 50 cases reach peak at the time of maximum precipitation intensity. Also, the variation of wet number and K-index corresponded with the variation of wind speed. It is found that the number of frequency of low-level jets with southwestward direction has been increased and these jets are mainly passed from the southwest toward to the northeast of the Korean peninsula in that time.