http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
불순물을 포함한 이산화탄소의 증발 열전달계수 압력강하 상관식 비교
정주희(Ju Hee Jeong),윤린(Rin Yun) 대한설비공학회 2021 설비공학 논문집 Vol.33 No.4
The evaporating heat transfer characteristics and the pressure drop of carbon dioxide, including impurities, were experimentally measured and compared with the predictions from existing models. The experimental setup consisted of a test section, a condenser, and a heating part. The test section used double-tube type, and the copper tube of 1/2 inch was located inside the PVC pipe. Total length of the test section was 4 meters. The temperature of carbon dioxide was measured by attaching the thermocouple to the test part using soldering. In addition, the temperature of the brine was measured by inserting the T-type thermocouple through the hole in the outer tube in order to measure the brine temperature in the PVC tube. The CO₂ mixture after the test section was condensed by using two plate-type heat exchangers. The impurity of nitrogen concentration was transformed by 1.0~5.0 wt.% under 400~500 kg․m<SUP>-2</SUP>s<SUP>-1</SUP> conditions. The heat transfer coefficients of pure CO₂ and CO₂+N₂ were compared by using the Shrock and Grossman model, the Gungor and Winterton model, and the Yoon et al.’s model. The pressure drops were compared using the Müller-Steinhagen model, the Heck and Chislom models, and the Yoon et al.’s model. The Yoon et al.’s model and the Chislom model showed the best performance when predicting the boiling heat transfer coefficient and pressure drop for the CO₂+N₂ mixture, respectively.
군집분석과 상세기상모델을 통한 포항지역 계절별 바람장 특성
정주희 ( Ju Hee Jeong ),오인보 ( In Bo Oh ),고대권 ( Dae Kwun Ko ),김유근 ( Yoo Keun Kim ) 한국환경과학회 2011 한국환경과학회지 Vol.20 No.6
The typical characteristics of seasonal winds were studied around the Pohang using two-stage (average linkage then k-means) clustering technique based on u- and v-component wind at 850 hpa from 2004 to 2006 (obtained the Pohang station) and a high-resolution (0.5 km grid for the finest domain) WRF-UCM model along with an up-to-date detailed land use data during the most predominant pattern in each season. The clustering analysis identified statistically distinct wind patterns (7, 4, 5, and 3 clusters) representing each spring, summer, fall, and winter. During the spring, the prevailed pattern (80 days) showed weak upper northwesterly flow and late sea-breeze. Especially at night, land-breeze developed along the shoreline was converged around Yeongil Bay. The representative pattern (92 days) in summer was weak upper southerly flow and intensified sea-breeze combined with sea surface wind. In addition, convergence zone between the large scale background flow and well-developed land-breeze was transported around inland (industrial and residential areas). The predominant wind distribution (94 days) in fall was similar to that of spring showing weak upper-level flow and distinct sea-land breeze circulation. On the other hand, the wind pattern (117 days) of high frequency in winter showed upper northwesterly and surface westerly flows, which was no change in daily wind direction.
정주희(Ju Hee Jeong),윤린(Rin Yun) 대한설비공학회 2021 설비공학 논문집 Vol.33 No.1
The characteristics of boiling heat transfer were experimentally investigated for carbon dioxide with nitrogen impurities. The experimental setup was composed of a test section, a condensation section for the liquefaction of carbon dioxide before entering the pump, and a heating section for controlling the temperature of the entrance of the test unit. The test section was comprised of a double tube heat exchanger. A copper tube with a length of 4 m and a 1/2-inch diameter was located inside and the PVC pipe used for heating was outside. T-type thermocouples were installed in the annulus space of the test section to measure the brine temperature in the PVC and the surfaces of the copper tube. The experiment was performed under a mass flux of 200~700 kg·m<SUP>-2</SUP>s<SUP>-1</SUP> at a nitrogen concentration of 1.0~5.0 mol% and 0.1~0.9 of vapor quality. The boiling heat transfer coefficient of carbon dioxide with impurities decreased by an average of 14.7% compared to pure carbon dioxide.
연구논문 : 수도권 대기질 모델링 정확도 향상을 위한 WRF모델링: 계절별 물리옵션 민감도 연구
정주희 ( Ju Hee Jeong ),오인보 ( In Bo Oh ),강윤희 ( Yoon Hee Kang ),방진희 ( Jin Hee Bang ),안혜연 ( Hye Yeon An ),석현배 ( Hyeon Bae Seok ),김유근 ( Yoo Keun Kim ),홍지형 ( Ji Hyung Hong ),김지영 ( Ji Young Kim ) 한국환경과학회 2016 한국환경과학회지 Vol.25 No.1
In order to improve the prediction of the regional air quality modeling in the Seoul metropolitan area, a sensitivity analysis using two PBL and microphysics (MP) options of the WRF model was performed during four seasons. The results from four sets of the simulation experiments (EXPs) showed that meteorological variables (especially wind field) were highly sensitive to the choice of PBL options (YSU or MYJ) and no significant differences were found depending on MP options (WDM6 or Morrison) regardless of specific time periods, i.e. day and night, during four seasons. Consequently, the EXPs being composed of YSU PBL option were identified to produce better results for meteorological elements (especially wind field) regardless of seasons. On the other hand, the accuracy of all simulations for summer and winter was somewhat lower than those for spring and autumn and the effect according to physics options was highly volatile by geographical characteristics of the observation site.
폭염 시 건물 외부공간의 온열환경 평가를 위한 지표의 수정회귀식에 대한 연구
정주희(Ju Hee Jeong),오병철(Byoung Chull Oh) 한국생태환경건축학회 2024 한국생태환경건축학회 논문집 Vol.24 No.1
Purpose: PMV and UTCI are key indices encompassing all major factors for assessing human thermal comfort. However, due to the complexity of calculations and significant errors arising from the inclusion of all these factors, there is a need for research on simpler indices that can be more easily applied. Therefore, in this study, we propose a modified formula for analyzing and evaluating thermal comfort in outdoor spaces during heatwaves, based on data collected in actual outdoor environments. Method: Employing the Stepwise method in multiple regression analysis, we analyzed existing PMV and UTCI to derive a modified regression model. Temperature (Ta), radiant temperature (Tr), relative humidity (RH), metabolic rate (Met), and clothing insulation (Clo) were used as variables. Result: The PMV equation demonstrated 99.3% explanatory power, while the UTCI equation showed 99.7%. The significance of deriving these formulas lies in the fact that they are based on data collected from outdoor environments rather than theoretical values. Especially considering the high accuracy but challenging usability of PMV and UTCI as evaluation metrics, once the reliability of the modified regression equations is confirmed, they are expected to be widely utilized in future research.