H₂O/LiBr+HO(CH₂)₃OH계 공냉형 이중효용 흡수식 냉방시스템의 사이클 해석

권오경,문춘근,윤정인,Kwon, Oh-Kyung,Moon, Choon-Geun,Yoon, Jung-In 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.2

A cycle analysis was achieved to predict the characteristics by comprehensive modeling and simulation of an air-cooled, double-effect absorption system using a new $H_2O/LiBr+HO(CH_2)_3OH$ solution. The simulation results showed that the new working fluid may provide the crystallization limit 8% higher than the conventional $H_2O/LiBr$ solution. With a crystallization margin of 3wt%(weight%), the optimal solution distribution ratio was found in the range of 36 to 40%. Variation of cooling air Inlet temperature has a sensitive effect on the cooling COP and corrosion problem. The simulation of heat exchangers with UA value revealed that the absorber and the evaporator are relatively important for an air-cooled system compared with the condenser and the low temperature generator. The effect of cooling air flow rate, circulation weak solution flow rate and chilled water inlet temperature were also examined. The new working fluid may provide the COP approximately 5% higher than the conventional $H_2O/LiBr$ solution.

반복세탁 및 전단·인정변형에 따른 텐셀직물의 피로도

권오경,이창미,김묘향,박희웅,Kwon, Oh-Kyung,Yi, Chang-Mi,Kim, Myo-Hyang,Park, Hee-Ung 한국의류산업학회 1999 한국의류산업학회지 Vol.1 No.3

This study was conducted to examine the fatigue phenomenon of mechanical properties in tencel fabrics by repeated washing & shear and tensile deformation. The obtained results are as follows. After performing repeated shear tensile deformation, RT of tencel showed higher increase rate than that of cotton and rayon, whereas its WT and EM was a smaller decrease rate than that of them. This means that tencel's resistance to tensile deformation was the greatest. In the repeated washing and shear tensile deformation, tencel's 2HB, 2HG and 2HG5 showed a remarkable increase rate. In terms of deformation frequency, the greatest change rate appeared at the time of 1000 cycles of repeated shear tensile deformation and 15 times of repeated washing. In the hand value and THV, KOSHI showed a higher increase rate for tencel than for cotton and rayon in both repeated washing and shear tensile deformation, and NUMERI showed a higher increase rate. In the THV the change rate of rayon and cotton could be rarely seen but for tencel, it decreased. tencel's change rate of thermal insulation value by materials was 1.08%, and it increased as the washing frequency increased, compared to the grey fabrics, whereas the change rates of cotton and rayon were 0.74% and 0.22%, respectively. The qmax decreased in the order of cotton>tencel>rayon as the washing frequency increased.

마직물 및 마혼방직물의 온열특성에 대한 흡습의 영향

권오경,이참미,성우경,Kwon, Oh-Kyung,Yi, Chang-Mi,Sung, Woo-Kyung 한국의류산업학회 1999 한국의류산업학회지 Vol.1 No.2

The thermal properies of the pure linen fabrics available in the market and linen blended woven fabrics were measured at the moisture content of 0%, 20%, 40% and 60% using KES-F7 system (Thermo Iabo II type). The experimental properties were statistically analyzed by the rate of water absorbent. The main results were as follows; There is a positive correlation between the thermal insulation value (TIV) and thickness of pure linen fabrics and linen blended woven fabrics by water absorption. Whereas an negative correlation exists between the TIV and cover factor. There is a high positive correlation among the thermal conductivity (k), thickness and weight of pure linen fabrics and linen blended woven fabrics by water absorption. Wherase a high negative correlation exist between the k and air' permeability (Ap). There is a high positive correlation between the feeling of warmth/coldness and bulk density of pure linen and linen blended woven fabrics by water absorption. Wherase a high negative correlation exists between the feeling of warmth/coldness and porosity. There is a negative correlation between TIV and $q_{max}$ of pure linen fabrics and linen blended woven fabrics. The higher the rate of water absorbent, the lower the TIV. This means that TIV decreases by water absorption. As for the thermal property by rate of water absorbent $q_{max}$ and k increase by water absorption and reach max-value at 60% rate of water absorbent. The TIV decreases by water absorption and has +value at 0% rate of water absorbent, whereas it has -value with a feeling of coldness at 20%, 40%. and 60% rate of water absorbent.

샘물의 구조성 발색과 바이오미메틱스 섬유

권오경,고재운,최영희,이상아,Kwon, Oh-Kyung,Kouh, Jae-Oon,Choi, Young-Hee,Lee, Sang-A 한국의류산업학회 2006 한국의류산업학회지 Vol.8 No.2

수직관 흡수기의 물질전달에 미치는 계면활성제의 영향

권오경,윤정인,윤재호,Kwon, Oh-Kyung,Yoon, Jung-In,Yun, Jae-Ho 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.5

This study was concerned with the enhancement of mass transfer by surfactant added to the aqueous solution of LiBr. Different vertical inner tubes were tested with and without an additive of normal octyl alcohol. The test tubes were a bare tube, groove tube, corrugate tube and inserted spring tubes. The additive concentration of normal octyl alcohol as a surfactant is about 0.08mass%. The Sherwood number was measured as a function of film Reynolds number 20~200. The experimental results were compared with those which use no surfactant. The enhancement of mass transfer by Marangoni convection effect which was generated by addition of the surfactant is proved for each testing tube Especially, it is clarified that the tube with the spring has the highest enhancement effect. A correlation of the experimental mass transfer data for the bare, groove, corrugate and insert spring tubes results expressed as the form of Sh=cㆍ Re$_{f}$ $^{n}$ .

Properties of Zn O Varistor Fabricated by Seed Grain Method

권오경,마재평,백수현,Kwon, Oh Kyung,Mah, Jae Pyung,Paek, Su Hyon The Institute of Electronics and Information Engin 1987 전자공학회논문지 Vol.24 No.3

We investgated I-V cahracteristics and relationship between microstructures and electrical properties in the specimens fabricated by seed grain method for low voltage Zn O varistor. Breaksown voltage was mainly dependent on seed grain size, and could be cntrolled to 10V/mm -15V/mm by sintering temperature and time. In non-seed grain method breakdown voltage generally agreed with final grain size, but did not always agree with it by the change of barrier phase distribution in case of the method using seed grains.

방진복 착용에 따른 인체의 온열생리적 특성 및 주관적 감각

권오경 ( Oh Kyung Kwon ),이창미 ( Chang Mi Yi ) 한국감성과학회 1998 춘계학술대회 Vol.1998 No.-

Dust-free garment prevents contamination which otherwise is caused by skin and clothes to protect from dust or dirt. Therefore, it requires high performance and should function as a working clothes. Clothes are a medium between human and thermal environmental system, and it is required to study human enviroment to ensure comfortableness of clothes and to satisfactorily go along with enviroment .This study investigates the physical and physiological features of dust-free garment used in the clean room at a semiconductor factory in oredr to scientifically clarify what the dust-free garmint is as well as to contribute to the design and development of high performance material and clothes. Three kinds of dust-free fabrics (DFG-I, DFG-II, DFG-III) which are being developed by a local company are used to manufacture dust-free garment. These dust-free garments are dressed and tested in such an enviroment as similar to semiconmemts with temperature at 23±1°C and humidity at 50±5%RH in order to investigate the thermo physiological and psychological features of human body. The results of this study are as follows. The results of this study are as follows. 1.The mean skin temperature was significantly different among the clothes, subjects and experimental time. Temperature tends to rise from the time of exercising load. Continuous motion coupled sealed clothes prevents heat transmittance, and temperature rises in the order of DFG-l, DFG-ll and DFG-lll as time course. 2.As for the skin temperature by local timperature is minimun on the head and torso and increares remarkably at the terminal part of human body. 3. As for the body mass loss was significantly higher in DFG-lll than DFG-l and DFG-ll. 4. Though there is no significant difference in the temperature within clothes among the kind of clothes temperature is 1°C higher in the back. Temperature within all the dust-free garments 29.7°C in the back and 31.3°C in the chest which belong to the comfort zone(31-33°C). The relative humidity is 39.7%RH in the chest and 33.8%RH in the back which is slightly below the comfort zone(40-60%RH) 5. The thermal sensation belong to the comfort zone regardless of the kinds of clothes. The subjects feels a slight fatigue as times goes. As for the subjective sense of subjects the mean skin temperature as well as temperature and humidity within clothes show similar tendency. This means that they relate with each other.

확산접합 콤팩트 열교환기의 성능에 관한 실험적 연구

권오경(Oh-Kyung Kwon),차동안(Dong-An Cha),윤재호(Jae-Ho Yun) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.1

The objectives of this paper are to study the characteristics of heat transfer and pressure drop of the micro channel heat exchangers using diffusion bonding technology. Four types of heat exchangers are designed and manufactured, which are straight type, long dot type, splited wavy type and straight double side type. Heat transfer and pressure drop performance of each heat exchangers are measured in various operating conditions, and compared each other. The results show that the (j/f)<SUP>1/3</SUP> performance of splited wavy type and long dot type increases about 10.3% and 6.1% at the Reynolds number 470 compared to that of straight type, respectively. On the other hand, (j/f)<SUP>1/3</SUP> performance of straight double side type decreases 19.7%.

컴퓨터 CPU 냉각용 미세채널 워터블록의 열성능에 관한 연구

권오경(Oh-Kyung Kwon),최미진(Mi-Jin Choi),차동안(Dong-An Cha),윤재호(Jae-Ho Yun) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.10

The object of this paper is to study on the thermal performance of a micro channel water block for computer CPU cooling. The effects of liquid flow rate, micro channel width and height on the thermal performances of water block are investigated experimentally. The water block was fabricated Al and machined with a micro milling. The water block consisted of rectangular micro channels 0.5 to 0.9㎜ width and 1.5 to 4.5 ㎜ height. The experiments were conducted using deionized water, over a liquid flow rate ranging from 0.2 to 2.0 ㎏/min. The base temperature and thermal resistance decrease with increasing of liquid flow rate. The increase of a channel height is more effective on the thermal resistance than the decrease of a channel width. At the flow rate of 0.7 ㎏/min, input power of 100W, the base temperature and thermal resistance of sample 6 is 33℃ and 0.13 ℃/W respectively.

지그재그채널 PCHE의 각도에 따른 열전달 및 압력강하특성

권오경(Oh-Kyung Kwon),최미진(Mi-Jin Choi),최영종(Young-Jong Choi) 대한설비공학회 2009 설비공학 논문집 Vol.21 No.9

The objectives of this paper are to study the characteristics of heat transfer and pressure drop of the zigzag channel PCHE using diffusion bonding technology by numerical analysis. PCHE of five types are designed, which are zigzag channel angle 180°, 160°, 140°, 120° and 100°. The zigzag PCHE was numerically investigated for Reynolds number in a range of 150~800. The temperatures of the hot side were performed at 80℃ while that of the cold side was conducted at 20℃. The results show that the performance of heat transfer rate for zigzag channel 100° increases about 11.5% compared to that of zigzag channel 180°. On the other hand, the performance of pressure drop for zigzag channel 100° is remarkably higher than that of zigzag channel 180°, about 2.4 times.