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CFD해석을 통한 직관덕트와 주름덕트의 공기 유동성능에 관한 연구
이공희(Gong-Hee Lee),윤의열(Ui-Yeol Yoon),전희호(Hee-Ho Jeon),이승준(Seung-Jun Lee) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
High-temperature electronic equipment dissipates heat by receiving cooled air from environmental control devices for effective heat dissipation. Due to space constraints and equipment operating environmental conditions, it is common to provide cooling air at a distance using air ducts. In this case, uniform and stable supply of cooling air is most important. But, the ducts are accompanied by flow losses and pressure variations due to changes in flow cross-sectional area, internal surface conditions, and flow velocity, and in particular, there is a difference in air flow characteristics depending on the cross-sectional shape of the duct. In this paper, the air flow performance of straight duct and flexible duct is compared by CFD(Computational Fluid Dynamics) analysis. As a result, it was confirmed that the air flow nonuniform and instability occurred due to the frictional resistance and the pressure difference of the flexible duct’s wrinkled portion.
열해석을 통한 소형 통신장비의 방열구조 최적설계에 관한 연구
이공희(Gong-Hee Lee),윤의열(Ui-Yeol Yoon),전희호(Hee-Ho Jeon),이승준(Seung-Jun Lee) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
In accordance with the demand for the portability and convenience, the communications equipment is being made increasingly smaller. The miniaturization of communications equipment is that the natural convection cooling by heat sink than forced convection cooling by fan is required, and the modules electronic components have been made integration. Accordingly, the reliability of heat dissipation was the important issue. In this paper, the temperature of the modules major electronic components should be satisfied with allowable temperature. So, we suggested the design optimization for a compact communications equipment using the heat sink. A commercial CFD(computational fluid dynamics) tool icepak 14.5 are used to optimize the structure of heat dissipation.
송풍기 유량센서의 운용온도와 센서수명 영향성에 관한 연구
이공희(Gong-Hee Lee),윤의열(Ui-Yeol Yoon),전희호(Hee-Ho Jeon),이승준(Seung-Jun Lee) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
The normal state of blower which is used for cooling device is very important for the equipment system protection. For that reason, the electronic system is identifying the normal state of the blower by mounting the air flow sensor to the blowers internal duct. The air flow rate sensor of the mechanical type, there is a problem that is occasionally broken. This caused more of sensor fracture I the operating conditions of elevated ambient temperature. It is estimated that operational temperature is affected a air flow sensor life. In this paper, It was confirmed the effect of the sensor life according to an operational temperature through FSI(Fluid & Structure interaction) analysis. ANSYS Fluent and Mechanical tool was used for FSI analysis. The sensors stress value due to the air flow rate of the blower was calculated by performing a fluid analysis, and it analyzed the sensors fatigue life at the room temperature and elevated temperature using the S-N diagram. As the results, the higher the temperature was confirmed that the sensor life is low, the sensor life is improved by the lowering of the ambient temperature.
박진양(Jin-Yang Park),전희호(Hee-Ho Jun),전용두(Yong-Du Jun),이금배(Kum-Bae Lee) 대한설비공학회 2007 설비공학 논문집 Vol.19 No.3
Opening an ancient tomb interior can deal fair damage for preservation in long period because of high moisture. In this study, a duct-type HVAC system was installed to preserve an ancient tomb and temperature and humidity was measured to analyze heat environment. Armhole was measured to search whether an ancient tomb receives effects of vibration caused by a duct-type HVAC system. According to the measured data, temperature in an ancient tomb is kept adaptively in conservation regardless of a duct-type HVAC system installation when it rains in summer. The other side, humidity is kept adaptively in conservation when installed duct-type HVAC system. But when it is in natural state, a lot of humidity by dew condensation phenomena. So it needs a duct-type system for an ancient tomb conservation. In the case of vibration, measurement value of 3 satisfy control but Germanic DIN 4150 does not satisfy. Therefore, equip must be such that it can prevent vibration for safety.
전용두(Yong-Du Jun),이금배(Kum-Bae Lee),박진양(Jin-Yang Park),고석보(Seok-Bo Ko),전희호(Hee-Ho Jun),윤영묵(Young-muk Youn) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.6
Although the importance of good conservation of historic sites including ancient royal tombs is well aware, still not much attention has been paid for the facilities and systems to preserve those historic sites, which includes precious artifacts as wall paints and carved works, etc. Even the level of general understanding about the environment of the underground space of tombs is not satisfactory. In Korea, researchers have recently begun addressing the importance of maintaining proper environment for underground space as of ancient tombs and are making efforts to develop suitable HVAC(heating, ventilating and air-conditioning) systems for them. In this study, an HVAC system for a tomb (D×W×H=1.3m×3.0m×1.2m) was installed to maintain suitable indoor conditions for conservation of tomb. The temperature and humidity inside the tomb were measured to represent the performance of the installed duct-type HVAC system. Vibration levels due to the installed an HVAC system are alive investigated experimentally. According to the measured data, the level of vibration inside the present model tomb with the duct-type unit showed significantly lower values than the case with the indoor unit inside.
대형용접구조물의 미세틈새가 구조 건전성에 미치는 영향성에 관한 연구
윤의열(Eui-Youl Yoon),이공희(Gong-Hee Lee),김창진(Chang-Jin Kim),전희호(Hee-Ho Jeon),이승준(Seung-Jun Lee) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
During the welding process, welding deformation is caused by the non-uniformity of the temperature distribution in the weldment. the geometrical shape of a Welding bead, Welding deformation and Gap have strong influence on the mechanical reliability such as fracture strength and fatigue life against large welding structure . In this study, Finite element analysis was used to figure out the Structural integrity correlation of the large welded structures caused by small gap. Based on the simulation results, small gap around welding conjunction has influence on structrual integrity. In conclusion, it was recommended that welding structure design be perfomed according to the proper welding procedure and considered minimizing small gap near the welding metal conjuction.
박진양(Jin-Yang Park),고석보(Seok-Bo Ko),전희호(Hee-Ho Jun),윤영묵(Young-muk Youn),이금배(Kum-Bae Lee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
In recent years the importance of the preservation of cultural artifacts like ancient tombs has been widely accepted domestically and internationally as the quality of life improves. However, not much attention has been paid for the facilities and systems to preserve those artifacts. Researchers have recently begun addressing the above issue and developing suitable system for the tomb conservation in Republic of Korea. In the present study, an duct-type HVAC system for a tomb (D×W×H=1.3m×3.0m×1.2m) was installed to maintain suitable indoor conditions for conservation of tomb. The temperature, humidity and condensed water inside the tomb are measured to estimate the dehumidification loads while the temperature and the humidity inside the tombs were maintained during the rainy season.