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곡률비 변화에 따른 이중관 나선형 열교환기의 열전달 특성에 관한 실험적 연구
금성민,이승로 한국기계기술학회 2023 한국기계기술학회지 Vol.25 No.6
The heat transfer characteristics of double-pipe spiral heat exchanger were investigated by various curvature sizes, experimentally. The three different sizes of heat exchanger were made and tested with water as a working fluid to analyze the heat transfer characteristics. The heat transfer rates, overall heat transfer coefficient and pressure drop were analyzed with various heat exchanger sizes (i.e., curvature ratios). As result, the heat transfer rate increased with increasing the size of the heat exchanger as the flow rate increased due to increasing the area size of heat transfer. However, the overall heat transfer coefficient and pressure drop increased with decreasing the heat exchanger size (i.e., increased curvature ratio) due to the enhanced centrifugal force and inertia.
저발열량 가스 연료의 비예혼합화염의 오염 물질 배출 특성에 관한 수치해석 연구
금성민,이승로 한국기계기술학회 2022 한국기계기술학회지 Vol.24 No.6
The characteristics of pollutant emission for non-premixed flames with LCG 8000 and LCG 6000 represented as low calorific gases were investigated by numerical simulation. Commercial software (ANSYS 16.2 - FLUENT) is used to predict 2-D pollutant emission with GRI 3.0 detailed reaction mechanism. In addition, the addition of hydrogen to LCG 6000 was also considered. As result, the flame length and temperature of LHVGs were decreased with decreasing calorific value at the same condition. In addition, NO concentration was decreased as temperature decreased. However, CO concentration for LCG 8000 predicted to be slightly higher than that for methane due to the high propane concentration. In the case of LCG 6000 with added hydrogen, the flame length was the shortest and NO concentration was the highest due to the highest flame temperature, but CO concentration decreased rapidly due to the addition of the carbon-free fuel.
저 발열량 가스 연료의 예혼합화염 연소 특성에 관한 연구
금성민 한국기계기술학회 2021 한국기계기술학회지 Vol.23 No.3
In this study, the combustion characteristics of low calorific gas (LCG) fuels are investigated by numerical simulation. PREMIXED code is used to predict the flame structure and NO emission with two mechanisms, which are GRI 3.0 and USC II chemical reaction mechanisms for CH4 and LCG 8000 and LCG 6000, respectively. Also, elementary reactions related with production and destruction for OH radical are studied because OH radical is dominant for burning velocity and NO emission. As results, the production and the destruction of OH radical for CH4 and LCG 8000 using GRI 3.0 are dominated by reactions of No. 4, No. 2 and No. 3 and by No. 5, No. 3 and No. 7, respectively. For LCG 6000 using USC II, reactions of No. 3, No. 4 and No. 11 and of No. 7, No. 8 and No. 12 dominates to the production and the destruction, respectively. In addition, NO emissions for LCG gas fuel are generated by thermal NO because the flame temperatures are over 1800 K.
산소부화화염내 CO<sub>2</sub>의 열 및 화학적 효과에 대한 연구
금성민,이창언,한지웅,Kum Sung Min,Lee Chang Eon,Han Ji Woong 대한기계학회 2005 大韓機械學會論文集B Vol.29 No.5
An analysis of the effects of $CO_{2}$ on fundamental combustion characteristics was performed in Oxygen enriched condition by comparing the laminar burning velocities, flame structures, fuel oxidation paths. Fictitious $CO_{2}$ was introduced to discriminate the chemical reaction effects of $CO_{2}$ from the thermal effects. PREMIX code was utilized to evaluate the laminar burning velocities. OPPDIF code was utilized to investigate the flame structure and fuel oxidation path variation. The contributions of thermal effects on laminar burning velocities are dominant at lowly oxygen-enriched condition but those of chemical reaction effects become dominant at highly oxygen-enriched condition. Chemical reaction effects caused the additional flame temperature decrease besides thermal effects and oxygen-leakage increase in non-premixed flame. Specific fuel oxidation path and CO production path is enhanced in spite of overall decrement of fuel consumption rate by chemical reaction effects of$CO_{2}$.
금성민 한국에너지학회 2004 에너지공학 Vol.13 No.1
?The objective of the study was to investigate the characteristics of heat transfer and flow in 2-dimensional impinging air jet system, in which trapezoid rods have been set up in front of impinging plate in order to increase heat transfer. Experiments were carried out first using without the rods to establish the baseline heat transfer performance. And this result compared with the experimentation with rods. When rods are installed in front of the impinging plate, the acceleration of the flow and the eddies due to the rods seem to contribute to the heat transfer enhancement. Heat transfer performance was best under the condition of C=1 mm and as the pitch is 30 mm. In this case, maximum rate of heat transfer augmentation is about 1.62 times greater compared to that without trapezoid rods
금성민,정동수,김종보,Geum, Seong-Min,Jeong, Dong-Su,Kim, Jong-Bo 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.5
The objective of this research was to investigate the enhancement of heat transfer by mesh in impinging air jet system. The technique used in this research is to place mesh as a turbulence promoter in front of the impinging plate. The heat transfer characteristics with and without mesh, the effect of clearances between impinging plate and mesh, the effect of distance between nozzle exit and impinging plate, and the effect of nozzle exit velocity have been studied experimentally. When mesh was installed in front of the impinging plate, heat transer has been increased due to the acceleration between rectangular holes and divided small jets. When clearances are changed, heat transfer comes to a maximum under the condition of C = 1 mm, irrespective of nozzle exit velocity or H/B. Also the average heat transfer enhancement with mesh has been increased about 44% under the condition of U = 18 m/s, H/B = 2 and C = 1 mm, compared to the result of a flat plate without mesh. And the results of this research are compared with existing heat transfer augmentation method by rectangular or circular rod.
충돌공기분류계(衝突空氣噴流系)에서 난류촉진체(亂流促進體)의 폭변화(幅變化)가 전열증진(傳熱增進)에 미치는 영향(影響)
금성민,서정윤,Kum, S.M.,Seo, J.Y. 대한설비공학회 1994 설비공학 논문집 Vol.6 No.4
This experimental study was earned out to examine the heat transfer characteristics of a 2-dimensional impinging air jet on a flat plate with a set of square rods. The objectives of the study were to investigate the flow and heat transfer characteristics caused by the square rods and to find out the optimum rods arrangement. Experiment was carried out first without using the rods to establish the baseline heat transfer performance. Then, rods of different widths and clearances were installed to cause the turbulence on the fluid flow.