• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.4
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• pp.355-363
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• 2022

Development of supersonic flying vehicle is one of the most latest issue in modern military technology. Specifically, structural integrity of supersonic flying vehicle can be verified by high temperature structural test. High temperature structural test is required to consider thermal load caused by aerodynamic heating while applying structural load simultaneously. Tubular quartz lamps are generally used to generate thermal load by emitting infrared radiation. In this study, modified heat flux model of tubular quartz lamp is proposed based on existing model. Parameters of the proposed model are optimized upon measured heat flux in three dimensions. Finally, thermal load of plate specimen is designed by the heat flux model. In conclusion, it is possible to predict heat flux applied on plate specimen and desired thermal load of high temperature structural test can be obtained.

• Tribology and Lubricants
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• v.17 no.4
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• pp.297-306
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• 2001

Under the condition of variable density and specific heat, maximum pressure, maximum temperature, bearing load, friction and side leakage in high-speed journal bearing operation are examined within some degree of Journal misalignment. The results are compared with the calculation results under the conditions of constant density and specific heat, and variable density and constant specific heat. It is found that the condition of variable density and specific heat play important roles in determining friction and load of Journal bearing at high speed operation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.45-49
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• 2013

High frequency system has been used for the purpose of skin care and obesity treatment, by high-frequency energy is applied to the human body generates deep heat. Conventional high frequency system could not selection control by depending on the body load fluctuations. Such as burns and side effects have been reported by system instability and then therapeutic effect is insufficient. During treatment, objective information about the status of the patient was no. Because of treatment methods are subjective, and so tailored treatments were impossible. In this paper, high frequency medical system with sinusoidal frequency characteristics without distortion of the Push pull switching scheme for pain relief therapy was designed. And control circuit that was designed by feedback using the output changes according to the body-load fluctuation. Last, power circuit for efficient control the heat generated from the hardware was proposed.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.9-16
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• 2004

Close-coupled catalyst (CCC) can reduce the engine cold-start emissions by utilizing the energy in the exhaust gas. However, in case the engine is operated at high engine speed and load condition, the catalytic converter may be damaged and eventually deactivated by thermal aging. Excess fuel is sometimes supplied intentionally to lower the exhaust gas temperature avoiding the thermal aging. This sacrifices the fuel economy and exhaust emissions. This paper describes the results of an exhaust heat exchanger to lower the exhaust gas temperature mainly under high load conditions. The heat exchanger was installed between the exhaust manifold and the inlet of close-coupled catalytic converter. The exhaust heat exchanger successfully decreased the exhaust gas temperature, which eliminated the requirement of fuel enrichment under high load conditions. However, the cooling of the exhaust gas through the heat exchanger may cause the deterioration of exhaust emissions at cold start due to the increment of catalyst light-off time.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.9
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• pp.455-462
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• 2017

The purpose of this study is to analyze heating and cooling load variation due to envelope retrofits in an old school building. In a previous study, envelope retrofit of an old school building resulted in annual energy consumption reduction. However, cooling energy consumption increased with the envelope retrofit. This is because of high internal heat generation rates in school buildings and internal heat cannot escape through windows or walls when the envelope's thermal performance improves. To clarify this assumption, thermal performance changes due to envelope retrofits were analyzed by simulation. Results revealed indoor temperature and inner window surface temperature increased with high insulation level of windows. Indoor heat loss through windows by conduction, convection and radiation decreased and resulted in an increase of cooling load in an old school building. From results of this study, energy saving impact of envelope retrofits in an old school building may not be significant because of high internal heat gain level in school buildings. In case of replacing windows in school buildings, local climate and internal heat gain level should be considered.

• Journal of the Korean housing association
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• v.11 no.2
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• pp.129-137
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• 2000

This study is about the difference of South and East facing Cooling load of Apartment s Houses using Dynamic Heat-flow Calculation. Therefore, the purpose of this study is come in to use Material for the Thermal Environments of Apartment Houses. The results of the analysis are below. (1) For the peak load of degree hour; The highest is "I" unit and the next high load is H, F, E, C, B, G, D and A unit for the south facing Apartment houses. The higher load is "H" unit and the next high load is I, E, F, B, C, G, D, A Unit for the east facing Apartment houses. (2) For the total load of degree day; The highest load is "I" unit and the next high load is H, G, F, E, C, B, D and A Unit for the south facing Apartment houses. The highest load is "H" unit and the next high load is I, G, E, F, B, C, D, A Unit for the east facing Apartment houses. (3) For the total load of degree day; The highest load is "H" Unit for the east facing Apartment houses and the Lowest load is "A" Unit for the south facing Apartment houses.is "A" Unit for the south facing Apartment houses.nt houses.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.41-46
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• 2003

The important problem in high speed spindles is to reduce and minimize the thermal effect by motor and bail bearings. Thermal characteristics according to the bearing pre-load and cooling condition are studied for the test spindl with grease lubrication and high frequency motor. Bearing and motor we main heat generation, and heat generation by ball bearings as a function of load, viscosity and gyroscopic moment effect are considered. Temperature distribution and thermal displacement according to the speed of spindle are measured by thermocouple and gap sensor. The results show that the fitting pre-load and cooling temperature are very effective to minimize the thermal effect by motor an ball bearings.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.305-310
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• 2001

Within some degree of journal misalignment, maximum pressure, maximum temperature, bearing load, friction and side leakage in high-speed journal bearing operation are examined under the condition of variable density and specific heat. The results are compared with the calculation results under the conditions of constant density and specific heat, and variable density and constant specific heat. It is found that the effects of variable density and specific heat on shaft misalignment are significant in determining the load capacity of a journal bearing operating at high speed.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.287-292
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• 2001

Under the condition of variable density and specific heat, maximum pressure, maximum temperature, bearing load, friction and side leakage in high-speed journal bearing operation are examined. The results are compared with the calculation results under the conditions of constant density and specific heat, and variable density and constant specific heat. It is found that the condition of variable density and specific heat play important roles in determining friction and load of journal bearing at high speed operation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1630-1637
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• 2002

A slab-wick heat pipe was fabricated and tested for applications where the condenser temperature is in a range of 80 to 12$0^{\circ}C$. The pipe material was 9.53 mm O.D. copper tube and the working fluids were ethanol and water. The total length of the heat pipe was 1.6 m, in which evaporator section was 1.4 m and the condenser was 0.10 m. The slab was a composite wick structure fabricated with STS316 wire screens. Thermal load was varied for a specified fill charge ratio and inclined angle. The optimum fill charge ratio was identified to be 110% based on a theoretical calculation of the pore space in the slab wick of the heat pipe. The maximum thermal load was 120W for ethanol and the same was 200W for water with the condenser temperature of 8$0^{\circ}C$. The thermal performance of the slab wick heat pipe is analysed in terms of temperature characteristics and thermal resistance against thermal load, tilt angle and fill charge ratio.