• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.41-46
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• 2002

Recently, the design and construction of massive concrete structures are increased, But, the temperature rise within a large concrete mass makes the construction of massive concrete structures be very difficult. Therefore, various techniques of the thermal stress control of the mass concrete have been widely used. One of them is pipe-cooling which reduces the temperature of concrete with flowing water. It was shown to be possible to construct the massive concrete foundation of urban bridge successfully by application of pipe-cooling system with steel pipe and water circulation. It was also found to expected to make it possible to reduce the probability of thermal crack development in a massive concrete foundation of urban bridge by pipe-cooling system.

• 설비공학논문집
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• 제23권1호
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• pp.54-60
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• 2011

Procedures for estimation of insulation thickness for a horizontal pipe for condensation control or personnel protection has been investigated, parallel to the previous work of a vertical wall case. Parameters include pipe diameter, emissivity, thermal conductivity, and operating temperatures. The results indicated that the surface emissivity plays a very important role in the design of insulation, specially for the case of high temperature application with low Bi. The effect of surface radiation in such case could be up to 65% of the total. Required insulation thickness for the surface temperature control increases as pipe diameter increases and as surface emissivity decreases. Adequate revision of specifications or standards to include newly invented insulation materials with high emissivity has been also suggested.

• 융복합기술연구소 논문집
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• 제10권1호
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• pp.37-40
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• 2020

Automotive battery system consists of various components such as battery cells, mechanical structures, cooling system, and control system. Recently, various computational technologies are required to develop an automotive battery system. Physics-based cell modeling is used for designing a new battery cell by conducting optimization of material selection and composition in electrodes. Structural analysis plays an important role in designing a protective system of battery system from mechanical shock and vibration. Thermal modeling is used in development of thermal management system to maintain the temperature of battery cells in safe range. Finally, vehicle simulation is conducted to validate the performance of electric vehicle with the developed battery system.

• Journal of Mechanical Science and Technology
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• 제19권5호
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• pp.1206-1215
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• 2005

The thermal stratification phenomena, frequently occurring in the component of nuclear power plant system such as pressurizer surge line, steam generator inlet nozzle, safety injection system (SIS), and chemical and volume control system (CVCS), can cause through-wall cracks, thermal fatigue, unexpected piping displacement and dislocation, and pipe support damage. The phenomenon is one of the unaccounted load in the design stage. However, the load have been found to be serious as nuclear power plant operation experience accumulates. In particular, the thermal stratification by the turbulent penetration or valve leak in the SIS and SCS pipe line can lead these safety systems to failure by the thermal fatigue. Therefore in this study an 1/10 scaledowned experimental rig had been designed and installed. And a series of experimental works had been executed to measure the temperature distribution (thermal stratification) in these systems by the turbulent penetration, valve leak, and heat transfer through valve. The results provide very valuable informations such as turbulent penetration depth, the possibility of thermal stratification by the heat transfer through valve, etc. Also the results are expected to be useful to understand the thermal stratification in these systems, establish the thermal strati­fication criteria and validate the calculation results by CFD Codes such as Fluent, Phenix, CFX.

• 한국항공우주학회지
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• 제39권5호
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• pp.466-473
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• 2011

인공위성의 열제어는 인공위성이 운용궤도상에서 겪는 고진공, 극한의 온도변화 환경에서 위성 구성품의 온도변화를 허용한계 온도 범위 내에서 유지하는데 목적이 있다. 본 연구에서는 저궤도 관측위성(LEO)의 광학탑재체에 대한 열해석 과정으로 열진공 시험 조건, 열진공 챔버의 형상, 위성 탑재체 내부의 열적 환경을 고려하여 열해석 모델을 구성하고 궤도 조건에 따른 열해석을 수행하였다. 또한 광학탑재체의 지상 열진공 시험 조건에 따른 열해석 수행하여 열진공 시험을 위한 시험조건을 정립하였다.

• International Journal of Fluid Machinery and Systems
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• 제9권4호
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• pp.370-381
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• 2016

As a single-channel pump is used for wastewater treatment, this particular pump type can prevent performance reduction or damage caused by foreign substances. However, the design methods for single-channel pumps are different and more difficult than those for general pumps. In this study, a design optimization method to improve the hydrodynamic performance of a single-channel pump impeller is implemented. Numerical analysis was carried out by solving three-dimensional steady-state incompressible Reynolds-averaged Navier-Stokes equations using the shear stress transport turbulence model. As a state-of-the-art impeller design method, two design variables related to controlling the internal cross-sectional flow area of a single-channel pump impeller were selected for optimization. Efficiency was used as the objective function and was numerically assessed at twelve design points selected by Latin hypercube sampling in the design space. An optimization process based on a radial basis neural network model was conducted systematically, and the performance of the optimum model was finally evaluated through an experimental test. Consequently, the optimum model showed improved performance compared with the base model, and the unstable flow components previously observed in the base model were suppressed remarkably well.

• 한국의류학회지
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• 제44권4호
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• pp.776-787
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• 2020

This study investigated physiological and subjective responses to different types of firefighter station uniforms made with various designs and materials. Six healthy males participated in this study that consisted of 20 min of rest, 30 min of treadmill exercise, and 30 min of recovery in a hot and humid environment (34℃ and 65%RH). The experimental clothing conditions were as follows. 1) a fitted T-shirt and trouser made of 100% polyester (FC-Uniform), and 2) flame retardant T-shirts made of acrylic and cotton as well as trousers with aramid and polyester, designed for overfitting (Control). There were no significant differences in the body temperature, and sweat rate between the two conditions; however, the heart rate with the FC-Uniform was significantly lower than Control (p=.025). The clothing microclimate temperature at the chest of the FC-Uniform was significantly lower than the Control (p=.037), and a difference of 1℃ was maintained until the recovery was complete. There were no significant differences in the subjective responses; however, participants experienced a humidity sensation faster with FC-Uniform in the recovery phase. The results indicate that changes in the design and material of firefighter station uniforms may have a positive influence on reducing the thermal stress of firefighters.

• 한국전산유체공학회지
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• 제11권3호
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• pp.8-13
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• 2006

The north panel of a geostationary satellite is used as one of the main radiators, on which communication equipment or bus equipment are installed. The thermal control of panel is designed by using embedded heat pipes and surface heat pipes (or external heat pipes) to spread out heat dissipated from equipment all over the radiator evenly and finally to reject the heat to the space through the radiator efficiently. This panel is also divided by several areas based on the operating temperature and dissipation of equipment in order to increase heat rejection capability of radiator. The thermal analysis is carried out for the hot case, Winter Solsitce EOL (End Of Life), in order to validate thermal design of the panel utilized 6 surface heat pipes and 8 embedded heat pipes. The sensitivity studies for the heat pipe failure case and no heat pipe case are performed and compared to its normal state. The heat transport capability of heat pipe is also obtained from these calculations.

• 한국산업융합학회 논문집
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• 제20권5호
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• pp.425-430
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• 2017

This study propose CAE analysis of fire damper and design of the damper control system. Through the design of the damper system for ANSYS-CFX heat transfer. As a result of the analysis, continuance equation of the damper control. Climate system. Finaily, We have obtained a fire damper solution by using orthogonal array. The fire damper of the set of fixture and alveolus are made by using a CAE software. Also, the optimum design offshore structures. The new H-120 class fire damper was designed. In the near future, fire resistance test was carried out to obtain class H-120 thermal insulation of fire dampers according to a hydrocarbon fire conditions. The test results showed that the insulation of the damper blade was an important factor in the fireproof performance of fire dampers concerning the coaming length minimum 500mm on the unexposed side as specified test standard.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.868-870
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• 1999

In this paper we obtain a discrete mathmatical model of a Boiler control system from expermental data, we find appropriate input signal and parameter estimation algorithm for identification of the Boiler control system in power plant. Under these conditions experimental data are collected from real system and parameters are estimated by the Recursive Least Square algorithm. The computer simulation results show the parameter estimation algorithm for identification and the effectiveness of controller design of the Boiler control system.