• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.1019-1020
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.717-718
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• 2009

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.643-646
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• 2017

In a liquid rocket engine using hydrocarbon fuels, cooling of the combustion chamber wall is necessary to prevent the combustion chamber wall from melting or structurally deforming due to high heat flux. Among the various methods, regenerative cooling, which uses fuel as a coolant and then injects it into the combustion process, has good performance. This study investigated the heat transfer characteristics of kerosene as a coolant by varying the copper cross-sectional area, the flow rate in the channel, and the current applied to the channel. Convective heat transfer occurred rapidly when the cross-sectional area of the copper channel was small and when the kerosene flow velocity was fast.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.154-156
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• 2008

A prototype of the desiccant cooling system with a regenerative evaporative cooler was built and tested for the performance evaluation. The regenerative evaporative cooler is to cool a stream of air using evaporative cooling effect without an inc6rease in the humidity ratio. It is comprised of multiple pairs of dry and wet channels and the evaporation water is supplied only to the wet channels. By redirecting a portion of the air flown out of the dry channel into the wet channel, the air can be cooled down to a temperature lower than its inlet wet-bulb temperature at the outlet end of the dry channels. Incorporating a regenerative evaporative cooler eliminates the need for deep dehumidification in the desiccant rotor that is necessary to achieve low air temperature in the system with a direct evaporative cooler. Subsequently, the regenerative evaporative cooler enables the use of low temperature heat source to regenerate the dehumidifier permitting the desiccant cooling system more beneficial compared with other thermal driven air conditioners. At the ARI condition with the regeneration temperature of $60^{\circ}C$, the prototype showed the cooling capacity of 4.4 kW and COP of 0.75.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.151-155
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• 2006

Elastic-viscoplastic structural analysis is performed for regenerative cooling chamber of liquid rocket thrust chamber using Bodner-Partom visco-plastic model. Strain rate test was also conducted for a copper alloy at various temperatures in order to get material constants of visco-plastic model used in the structural analysis. Material constants of visco-plastic model were obtained from strain rate test results and visco-plsstic model was incorporated into finite element program, Marc, by means of user subroutine. The structural analysis results indicate that the deformation of cooling channel is mostly caused by thermal loading rather than pressure loading and confirmed structural stability of the cooling channel under operating condition.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.69-76
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• 2006

Elastic-viscoplastic structural analysis has been performed for regenerative cooling chamber of liquid rocket thrust chamber using Bodner-Partom visco-plastic model. Strain rate test was conducted for a copper alloy at various temperatures in order to get material constants of visco-plastic model used in the structural analysis. Material constants of visco-plastic model were obtained from strain rate test results and visco-plastic model was incorporated into finite element program, Marc, by means of a user subroutine. The structural analysis results indicated that the deformation of cooling channel is mostly caused by thermal loading rather than pressure loading and confirmed structural stability of the cooling channel under the operating condition.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.31-36
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• 2003

Recently, the power consumption and heat generation in an electronic equipment increase as the components are miniaturized and the computing speed becomes faster. Effective cooling method is required to ensure the guaranteed performance and reliable operation of the electronic devices. The aim of the present study is to investigate the cooling characteristics of a pin-fin heat exchanger as a candidate for cooling system of the electronic devices. Various configuration of the pin-fin array is selected in order to find out the effect of spacing and diameter of the pin-fin on the heat transfer characteristics. The results are compared with the experimental data or correlations of several researchers for the channel flow with pin-fin arrays.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.370-373
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• 2008

It is known that the temperatures of die, punch, holder and punch pad need to be kept different to get better formability in Mg sheet forming processes. Heating and cooling channels are usually equipped in each tool to assign different temperature. This study focused on the optimal design of the heating and cooling channels for a cross-shaped deep drawing die set. While the die and blankholder were heated to and kept at $250^{\circ}C$ by using heat cartridges, the punch and punch pad were kept at much lower temperature than that of the die and blankholder by water circulating through cooling channels. All the approaches were done by numerical analyses, aiming to maximize the cup height and to minimize the punch corner radius without any failure.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.185-192
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• 2012

The paper presents the development of a cooling circuit design system that automatically creates 3D cooling circuit on a given section plane conforming to design specifications, generates 3D solid model of cooling line segments defined on a 2D sketch plane, and verifies interference of 3D cooling channel with the molding die surface. The system was developed mainly for designing plastic injection molding die of vehicular lamp, which helps the mold designer to rapidly construct cooling circuits but also reduce designer's unintended mistakes by conforming to the dimensional design specifications. It is used by an injection molding die manufacturing company in Korea, and reported approximately 20% reduction of cooling channel design time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.580-584
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• 2004

In the present study, an evaluation technology for heating channel layout was investigated in SMC molding system design. Conventional design rules of cooling channel in injection molding process were applied to the present work. Finite element thermal analysis with ANSYSTM was performed to evaluate the temperature distribution of mold surface. SMC mold was manufactured to test the effect of a proposed heating channel layout system on the temperature distribution of mold surface and infrared camera was applied to a measurement of temperature. It was shown that infrared camera application was possible in a measurement of temperature distribution on mold surface.