• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.172-173
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• 2007

As the power density and switching frequency increase, thermal analysis of power electronics system becomes imperative. The thermal analysis provides valuable information on the semiconductor rating, long-term reliability. In this paper, thermal distribution of the Non Punchthrough(NPT) Insulated Gate Bipolar Transistor has been studied. For analysis of thermal distribution, we obtained experimental and simulation results by using finite element simulator, Ansys and by using photographic infrared thermometer, we compared experimental date with simulation result. and got good agreement. Also this paper provided thermal distribution of IGBT connected to heat sinks. and this results will be good information to design optimal heat sink for IGBT.

• 환경영향평가
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• 제22권5호
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• pp.513-523
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• 2013

This purpose of this work is to explore the characteristics of urban thermal environment distribution with the case of Daejeon. To do that, this work applied GIS Spatial Statistics to the LandSAT images gathered from 2000 to 2011. The urban thermal environment distribution at the time point of 2 showed high spatial autocorrelation. Therefore, it is judged that spatial autocorrelation is needed to increase the reliability and explanatory power of the characteristics of thermal environment distribution. In the case of the thermal in Daejeon, its positive clustering appeared high at the time point of 2, and its clustering in 2011 more gradually decreased than that in 2000 to 2011. In particular, given the decrease in the core H-H region, it was found that the thermal environment of Daejeon was greatly improved. However, since the rise in the region L-L means another changed like construction of a new city, it is judged that it is necessary to come up with a proper plan. It is considered that this analysis of the characteristics of urban thermal environment distribution in consideration of spatial autocorrelation L-L be useful for providing a fundamental material necessary for the policy and project of thermal environment improvement.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.942-944
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• 2017

초고속 비행체는 발사 시 엔진에 의한 음향 압력과 비행 중 공력 가열 및 공기역학적 압력 등 복합적인 하중을 받는다. 이러한 외부환경으로부터 비행체의 연료 탱크 등 내부 시스템을 보호하기 위해 열방어 시스템 패널(Thermal Protection System Panel)이 필요하다. 본 논문에서는 온도 조건에 대해 유한차분법을 이용하여 열방어 시스템 패널의 열전달 모델을 정의하고, 구한 절점별 온도 데이터를 회귀분석을 통해 두께방향 온도 구배의 함수로 정리하였다. 도출한 온도 이력과 극한 압력 하에서 열방어 시스템 패널의 열구조 특성에 대한 해석적 모델을 정의하였다. 해석적 모델을 이용하여 열방어 시스템 패널의 열구조 특성에 대해 매개변수 분석을 수행하였다. 이를 통해 열방어 시스템 패널의 경량화 및 열구조적 설계 요구조건을 충족하는 설계변수를 도출하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.463-464
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• 2008

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.773-776
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• 2005

In this paper, For improving the positioning accuracy of hydrostatic table, relationship between temperature of atmosphere and thermal characteristics of hydrostatic table is analyzed, and influence of thermal characteristics on positioning accuracy is also analyzed experimentally. From the experimental results, it is confirmed that positioning error and repeatability is $0.21{\mu}m\;and\;0.18{\mu}m$ when the laser scale which has $0.01{\mu}m$ of resolution is used as feed-back unit. and also confirmed that thermal deformation of scale and supporter, which occurs by the temperature variation of atmosphere, works as limit of repeatability in long time operation.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1503-1510
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• 2017

In this paper, a thermal analysis of a high speed induction motor with a PWM voltage source was performed by considering harmonic loss components. The electromagnetic analysis of the high speed induction motor was conducted using the time-varying finite element method, and its thermal characteristics were carried out using the lump-circuit method. Harmonic losses from tests in the high frequency region were divided into core loss and conductor loss components using various ratios, in order to determine the loss distributions for the thermal analysis. The results from both the calculations and experiment were validated using a high speed induction motor prototype operating at 20,000rpm.

• 한국기계가공학회지
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• 제14권5호
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• pp.113-119
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• 2015

The technical development of electric vehicles has been actively proceeding because of the reduction of oil resources and need for eco-friendly vehicle technology. In particular, an electronic control unit is an important element in the technology of electric vehicles due to the motor drive system. This paper concerns an experimental study on the thermal analysis of the steering control ECU structure for an electric vehicle. The ECU unit is designed for eight heat sinks for the thermal analysis of the ECU structure. The thermal analysis characteristics of the ECU structure are evaluated by the temperature distribution, heat flow, von Mises stress, total translation, and external surface temperature measurement of the ECU unit.

• 항공우주시스템공학회지
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• 제16권3호
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• pp.84-92
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• 2022

전기-정유압식 작동기(EHA)는 독립적으로 유동력원을 운용함에 따라, 복잡한 유압 배관을 제거할 수 있어 누유 및 중량 최소화, 안전성 향상의 장점이 있어 최근 항공기용 비행제어 분야에서 사용되고 있다. 이러한 EHA를 탑재하는 항공기의 경우, 기존 중앙 유압시스템을 탑재한 항공기에 비해 제한된 냉각원에 따른 EHA의 열관리 이슈가 대두된다. 이러한 열관리 이슈의 해결을 위해서는, EHA의 열특성을 예측할 수 있는 열해석 모델이 필요하다. 본 연구에서는 유압펌프 및 전기모터로 구성되는 EHA 유압동력모듈의 내부 회전체를 고압 하에서 고속으로 회전이 가능하도록, 유압동력모듈 내부에 유체 순환 회로를 적용하였다. 적합한 열해석 모델을 구축하고, 유냉식 또는 비유냉식 유압동력모듈 적용에 따른 해석 결과의 비교 및 검토를 통해 EHA의 열특성 영향성을 확인하고자 하였다.

• 설비공학논문집
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• 제18권1호
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• pp.73-80
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• 2006

Present study is concerned with an experimental study on the cooling characteristics of heat-generating components arranged in channels which are made by printed circuit boards. To assess the thermal performance of the heat-generating components arranged by $5\times11$ in flow channel, three variables are used: the velocity of the fluid at the entrance, the height of channel, and row number of the component. The cooling characteristics of the heat-generating components such as the surface temperature rise, the adiabatic temperature rise, the adiabatic heat transfer coefficient, and the effect of thermal wake are compared with the result of the experiment and the numerical analysis. Based on the experiment analysis, some conclusions can be drawn: First of all, the experiment and numerical analysis are identical comparatively; the heat transfer coefficient increases as H/B decreases. Howeve., when H/B is over 7.2, the effect of H/B is rather trivial. The effect is the biggest at the first component from the entrance, and it decreases until the fully developed flow, where it becomes very consistent. The thermal wake function calculated for each row decreases as H/B increases.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.165-168
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• 2008

A numerical analysis was conducted to predict the heat transfer characteristics of a solar receiver which is subject to very high heat fluxes and temperatures for solar thermal applications. The concentration ratio of the solar receiver ranges 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. This study deals with a solar receiver according to internal geometry variation incorporating high-temperature heat pipe. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 mm and the length was 400 mm and the angle of receiver end wall set $90^{\circ},\;60^{\circ},\;45^{\circ},\;30^{\circ}$. And the diameter of the heat pipe was 12.7 mm, 48 axial channels of the same dimensions were attached to the outer wall of the receiver with even spacing in the circumferential direction. The channels are changed to high-temperature sodium heat pipes. Commercial softwares were employed to deal with the radiative heat transfer inside the receiver cavity and the convection heat transfer along the channels. The numerical results are compared and analyzed from the view point of high-temperature solar receiver.