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수직평판(垂直平板)에 부착(附着)된 수평(水平)핀에서의 자연대류(自然對流)
김선정,이정철,서리수,권순석,Kim, S.J.,Lee, J.C.,Seo, L.S.,Kwon, S.S. 대한설비공학회 1988 설비저널 Vol.17 No.4
A study has been conducted experimentally on natural convection heat transfer characteristics of a vertical flat plate with horizontal rectangular fins in air. The effects of fin heights and Rayleigh numbers are mainly investigated. The experimental results are as follows; 1. The mean fin, plate and total Nusselt numbers decrease as dimensionless fin heights H/S increase at $0.50{\leq}H/S{\leq}2.00$. 2. The mean fin surface Nusselt number in case of H/S = 0.50 and $Ra_c=4.33{\times}10^3$ shows its maximum at $X_1$, surface where there is no interference with other fins. 3. Owing to the interference of fins the mean plate Nusselt numbers at H/S=0.50 and 2.00 for $Ra_S=6.57{\times}10^3$ are 35% and 80% respectively less than the mean fin Nusselt numbers. 4. The mean fin, plate and total Nusselt numbers of horizontal rectangular fins show higher values at short fins, but lower values at long fins than those of upward vertical fins.
루우버 위치(位置)가 루우버핀 열교환기(熱交換器)의 공기측열전달(空氣側熱傳達)에 미치는 영향(影響)
김선정,정태현,권순석,Kim, S.J.,Chung, T.H.,Kwon, S.S. 대한설비공학회 1990 설비공학 논문집 Vol.2 No.2
A Study has been conducted experimentally on heat transfer characteristics of louvered fin heat exchangers with various louvered positions in air. The experimental results are as follows; 1. Mean heat transfer coefficient is increased with increasing air velocity and decreasing temperature difference. The maximum value of heat transfer coefficient shows at 10㎜ backward louvered fins. 2. Pressure drop is increased with increasing air velocity and apparently depended on the louvered positions at V>10m/sec. 3. $\bar{h}/{\Delta}P$ is decreased with increasing air velocity and its maximum value shows at 10mm forward louvered fins and its minimum value shows at plate fins.
핀 간격(間隔)이 루우버핀 열교환기(熱交換器)의 공기측(空氣側) 열전달(熱傳達)에 미치는 영향(影響)
김선정,정태현,권순석,Kim, S.J.,Chung, T.H.,Kwon, S.S. 대한설비공학회 1990 설비공학 논문집 Vol.2 No.4
A study has been conducted experimentally on heat transfer characteristics of louvered fin heat exchangers with various fin spacings in air. The experimental results are as follows; 1. Mean heat transfer coefficient is increased with increasing air velocity and the optimum fin spacing shows at S=5mm. 2. Pressure drop is increased with increasing air velocity and its maximum value shows at S=3.5mm and its minimum value shows at S=6mm. 3. $\bar{h}/{\Delta}P$ is decreased with increasing air velocity and its maximum value shows at S=5mm and its minimum value shows at S=3.5mm.
조성관,김선정,정병옥,김재진,최규석,이영무 ( S . K . Cho,S . J . Kim,B . O . Jung,J . J . Kim,K . S . Choi,Y . M . Lee ) 한국공업화학회 1994 공업화학 Vol.5 No.5
게껍질로부터 Hackman법으로 키틴을 추출하였고 키토산은 이것을 일정 온도(100℃)에서 NaOH 용액의 농도와 반응 시간을 변화시켜 각각의 탈아세틸화 정도에 따라 제조하였다. 제조한 시료들은 A=19%, B=52%, C=70% 그리고 D=93%의 탈아세틸화된 것을 사용해 여러 가지 시험을 하였다. 분자량은 탈아세틸화도가 증가함에 따라 감소되는 현상을 나타냈고, 폐수처리 효과에 있어서 SS 제거율은 탈아세틸화도가 증가함에 따라 증가하였고 pH 9에서 우수한 성능을 나타냈으며, COD 제거율은 중성 영역에서 가장 좋게 나타났다. Chitin was extracted from crab shell by Hackman method and chitosan was prepared to chitin, that was deacetylated under various concentration of NaOH solution and reaction time at constant temperature, 100℃. Samples were A=19%, B=52%, C=70% and D=93% deacetylation`s chitosan and they were tested. When deacetylation was increased, Mw ̄ was decreased and removal rate of suspended solid and removal rate of chemical oxygen demand were increased. Suspended solid and removal rate of chemical oxygen demand showed the better at pH 9 and pH 7 than any other pH range.
[論文] 水平平板에 附着된 핀配列에서의 自然對流 熱傳達에 관한 實驗的 硏究
오원균(W.K.Oh),조진호(J.H.Cho),김선정(S.J.Kim),권순석(S.S.Kwon) 한국자동차공학회 1988 오토저널 Vol.10 No.1
A study has been conducted experimentally on the natural convection heat transfer characteristics of fin arrays on a horizontal flat plate in air. The effects of fin heights and Rayleigh numbers are mainly investigated.<br/> The experimental results are as follows;<br/> 1. The mean fin and mean total Nusselt numbers increase as dimensionless fin heights increase at 0.67≤H/S≤1.67. The mean plate Nusselt numbers increase in case of upward facing fins, but they decrease in case of downward facing fins. <br/> 2. The mean Nusselt numbers increase as Rayleigh numbers increase. 3. The mean fin surface Nusselt numbers has its maximum outside surface (Y₁) where there is no interference from each other fin.<br/> 4. The mean total Nusselt numbers in case of upward facing fins increase by 47% and 26%, respectively at H/S = 0.67 and 1.67 than those in case of downward facing fins for Ra_s = 6.50 X 10³.<br/>