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자동차 LED 전조등의 방열을 위한 히트싱크의 수치해석적 연구
정현호(Hyeon Ho Jung),김창오(Chang Oh Kim),정낙규(Nak Kyu Chung) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5
본 논문은 자동차 LED 전조등의 냉각을 위한 히트싱크의 설계요소를 변화시켜 방열성능을 알아보고자 시뮬레이션을 실시했다. 시뮬레이션에 적용한 히트싱크는 LED를 광원으로 사용하는 기존제품(Type 1)을 바탕으로 한정된 내부공간에 적합하도록 계산식에 의해 설계하여 5가지 유형으로 설계하였다. 이와 같이 설계된 히트싱크는 ANSYS CFD V12.1 의해 수치해석 하였고, 시뮬레이션의 결과는 히트싱크의 변화에 따른 온도분포와 평균온도, 공기유동특성 열유속 등으로 분석했다. 본 논문을 통하여 방열판의 구조와 휜 형상에 따른 냉각성능의 상관관계를 도출할 수 있었다. 설계된 히트싱크의 온도분포, 공기의 유동특성, 열유속에 대한 수치해석을 통하여 히트싱크 Type 2가 종합적으로 가장 좋은 결과를 확인 할 수 있었다. 또한 LED 전조등의 한정된 공간에서의 냉각특성 및 유동특성을 수치해석에 의해 분석함으로서 냉각시스템의 최적설계와 제작이 가능 할 것으로 사료된다. This thesis was conducted a simulation on the radiant heat performance according to factors of design of heat sink for cooling of the automotive LED head lamp. The heat sinks were designed with 5 different types to fit the limited internal space by formula based on an existing product (Type 1). Designed heat sinks of five types were analyzed by ANSYS CFD V12.1, and the analysis results were compared with the existing type. The results of simulation were analyzed temperature distribution and average temperature, air flow characteristic, heat flux etc. This thesis was researched on the correlation of the cooling performance according to the heat sink structure and the fin shape. Through numerical analysis, could be confirmed heat sink Type 2 as the best results. In addition, by this study in regard to the heat radiant and flow characteristics of LED head lamp at the limited internal space is thought possible to optimal heat sink design and production.
직사각형 밀폐공간내에 기체연료 옆면 누출시 가연혼합기 생성에 관한 연구
정낙규 朝鮮大學校 機械技術硏究所 1998 機械技術硏究 Vol.1 No.1
Theoretical analysis is applied to obtain the basic information for the prevention of explosion in a rectangular enclosure with gaseous fuel leak. Characteristics of flammable mixture formation such as distribution of flow and fuel mass fraction at various locations in the enclosure are determined for the following parameters : leak location, leak velocity and aspect ratio. As the leak velocity and leak time increase, the flammable mixture extends faster and wider. The higher leak location is the futher mass transfer is downward due to the gravitational force. Aspect ratio of the rectangular enclosure also affects the formation of flammable mixture proportional to the leak time and the leak velocity.
TMA 포접화합물에 첨가제를 첨가한 경우의 열물성에 관한 연구
김창오,강승현,김광일,정종헌,정낙규,김진흥 조선대학교 에너지.자원신기술연구소 2003 에너지·자원신기술연구소 논문지 Vol.25 No.2
TMA clathrate that is used as PCM of low temperature thermal storage system in this research creates hydrate crystallization at higher temperature than pure water, and its application is expected as PCM because of comparatively big latent heat without phase separation phenomenon. Ethylene Glycol is used as additive and evaluated experimentally for the purpose of the improvement in subcooling of TMA clathrate. In view of the results so far achieved subcooling is improved, the running time of the refrigerator is reduced. Thus the results are expected to use for the increase of coefficient of performance of low temperature thermal storage system in the building.