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열전달 촉진 핀-관 열교환기의 공기측 압력강화 및 열전달 특성에 관한 실험
윤백,길용현,박현연,김영생,Youn, Baek,Kil, Yong Hyun,Park, Hyun Yeon,Kim, Young Saeng 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.11
Heat transfer and pressure drop for ${\phi}10.07$ dry surface fin-tube heat exchanger with wave and wave-slit fins were measured for different fin spacings and number of tube rows. Longitudinal and transverse tube spacings of the heat exchangers are 21.65mm and 25mm respectively, and wave depth of wave fin is 1.5mm. The experiments were performed for 4 different fin spacings, 1.3, 1.5, 1.7 and 2.0mm, and the number of tube rows were 1,2 and 3 rows. The present results were compared with the previous results for the wave depth of 2mm. Also hydrophilic coated and bare fins were tested. Correlations for Colburn j-factor and friction factor were developed.
저속 영역에서 루버휜이 장착된 평판관형 알루미늄 열교환기의 공기측 전열 성능에 대한 실험적 연구
조진표,오왕규,김내현,윤백,Cho, Jin-Pyo,Oh, Wang-Kyu,Kim, Nae-Hyun,Youn, Baek 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.12
The heat transfer and pressure drop characteristics of heat exchangers with louver fins were experimentally investigated. The samples had small fin pitches (1.0 mm to 1.4 mm), and experiments were conducted up to a very low frontal air velocity (as low as 0.3 m/s). At a certain Reynolds number (critical Reynolds number), the flattening of the heat transfer coefficient curve was observed. The critical Reynolds number was insensitive to the louver angle, and decreased as the louver pitch to fin pitch ratio (L$_{p}$F$_{p}$) decreased. Existing correlations on the critical Reynolds number did not adequately predict the data. It is suggested that, for proper assessment of the heat transfer behavior, the louver pattern in addition to the flow characterization need to be considered. The heat transfer coefficient increased as the fin pitch decreased. At low Reynolds numbers, however, the trend was reversed. Possible explanation is provided considering the louver pattern between neighboring fins. Different from the heat transfer coefficient, the friction factor did not show the flattening characteristic. The reason may be attributed to the form drag by louvers, which offsets the decreased skin friction at a low Reynolds number. The friction factor increased as the fin pitch decreased and the louver angle increased. A new correlation predicted 92% of the heat transfer coefficient and 90% of the friction factor within $\pm$10%.10%.
조홍기 (Honggi Cho),윤백 (Baek Youn),김중호 (Jungho Kim) 대한설비공학회 2012 대한설비공학회 학술발표대회논문집 Vol.2012 No.6
The Characteristics of heat transfer and pressure drop in a concentric heat exchanger with inner tube was investigated by using a commercial CFD program. Four different inner tubes were studied. Bare tube has no fin and SPL 1, 2 and 3 have fin spirally attached on their surface. In case of SPL 1 & 3, the fin pitch is same with 1.18mm and the fin shape is triangular. However, the fin height is 1.00mm and 1.20mm for SPL 1 & 3, respectively. The fin height of SPL 2 is 1.05mm and the fin shape looks like an airfoil. The fin pitch of SPL 2 is 1.05mm. For all inner tubes with fin, the heat transfer rate increased from 1.8 to 2.3 times and the pressure drop increased from 5.5 to 8.6 times bare tube. SPL 3 with the highest fin height of 1.20mm showed the largest heat transfer rate, also the pressure drop increased significantly. It is seen that SPL 2 shows the best heat transfer and pressure drop characteristics, since SPL 2 showed similar heat transfer rate with SPL 3 but lower pressure drop by 17% than SPL 3. Since heat transfer and pressure drop strongly depend on the fin geometry of inner tube and have a trade-off relationship, the fin geometry should be selected for its application and condition.
탈취필터 내 첨착활성탄의 쏠림 형태와 충전율에 따른 탈취성능에 대한 실험
도수윤(Soo Yun Doh),김관택(Gwantaek Kim),윤백(Baek Youn),김현정(Hyunjung Kim),진유성(Yu-Sung Jin),문연진(Yeon-Jin Moon),김중호(Jung-ho Kim) 대한설비공학회 2021 대한설비공학회 학술발표대회논문집 Vol.2021 No.6
Recently, interest in indoor air quality has been increasing, and purification of various harmful gases generated indoors, along with fine dust, is drawing attention as an important factor. Deodorization filters, which typically use impregnated activated carbon, are used with dust collection filters to remove these harmful gases. Plate deodorization filters using impregnated activated carbon generally consist of small cells of a certain shape, and are made by filling impregnated activated carbon in the form of small grains formed by mixing impregnated activated carbon powder and adhesive, and attaching nets on both sides. This process of charging impregnated activated carbon is usually carried out manually, and therefore, uniform charging is not achieved, which can lead to the concentration of impregnated activated carbon. In this study, the deodorization performance was evaluated by measuring the purification rate of the five major harmful gases (formaldehyde, acetaldehyde, acetic acid, ammonia, and toluene) through experiments on various forms of impregnated activated carbon non-uniform charging forms. We also measure the change in deodorization performance with changes in various charge based on the charge of 220g (100% charge rate). Therefore, the results of this study are considered to be an important reference for establishing criteria for managing processes and quality in the manufacture of deodorized filters in the future by considering the phenomenon of non-uniform charging and the impact of charging rates on performance.