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Young-Deuk Kim(김영득),Jung-Gil Lee(이정길),Woo-Seung Kim(김우승),June-Seok Choi(최준석) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
In this study, the experimental and theoretical studies have been carried out to achieve a more comprehensive and systematic understandings on the fundamentals in heat and mass transfer through a commercial flat sheet composite membrane that employs different types of spacers in bulk feed and permeate flow channels. The commercial composite membrane used is comprised of an active layer of polytetrafluoroethylene (PTFE) and a scrim-backing support layer of polypropylene (PP), and its performance has been tested in the DCMD process. The different types of polypropylene and nylon mesh spacers have been used at both sides of the composite membrane as a support and turbulence promoter. In DCMD process the water vapor passes through the dry membrane pores, driven by the vapor partial pressure difference imposed between the liquid–vapor interfaces. The mass transport through the composite membrane can be described by two individual transfer paths: (i) polytetrafluoroethylene active layer not covered by polypropylene scrim support layer at the permeate side (i.e., effective open area for diffusion) and (ii) composite polytetrafluoroethylene active and polypropylene support layers. The influence of the spacers on the permeate flux enhancement in DCMD process with a PTFE/PP composite membrane has been examined experimentally and theoretically. The heat transfer coefficients are evaluated and correlated with the spacer geometries, hydrodynamic angle and voidage.
디젤엔진의 NO<SUB>x</SUB> 저감을 위한 SCR DeNO<SUB>x</SUB> 촉매의 정상 및 비정상 성능해석
김영득(Young-Deuk Kim),심성민(Sung-Min Shim),정수진(Soo-Jin Jeong),김우승(Woo-Seung Kim) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The steady- and unsteady-state kinetics of the selective catalytic reduction (SCR) of NOx with NH₃ has been investigated over a commercial V₂O?/TiO₂ catalyst. In order to account for the influence of transport effects the kinetics are coupled with a fully transient two-phase 1D+1D monolith channel model. The Langmuir-Hinshelwood (L-H) and Modified Redox (MR) mechanisms are adopted to describe the steady-state kinetic behavior of the V₂O?/TiO₂ catalyst, and their results are compared with each other. A Temkin-type kinetics is used to describe the ammonia adsorption/desorption rate. The reaction rate expressions are based on previously reported papers and are modified to fit the experimental data. The steady-state chemical reaction schemes used in the present mathematical model have been validated extensively with experimental data over a wide range of reaction temperatures.
간접 가열방식의 연속식 열처리로내 판(Plate) 온도해석에 관한 연구
김영득(Young-Deuk Kim),강덕홍(Deok-Hong Kang),김기홍(Ki-Hong Kim),김우승(Woo-Seung Kim) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
This study has been performed to predict the transient thermal behavior of the plate with the furnace geometry, material properties and operating conditions of the furnace as input parameters. The temperature profiles in the plate are determined using transient one-dimensional heat conduction equations. To verify the validity of the present numerical results, the present results obtained from the transient analysis are compared with those of experiments. Extensive parametric investigations are performed to examine the effects of plate and refractory emissivities, plate thickness and velocity, as well as change in gas temperature, on the thermal behavior of the plate.
급가감속 운전에 따른 듀얼 모노리스형 촉매변환기 내의 유동 균일도와 압력 강하에 관한 연구
김영득(Young-Deuk Kim),정수진(Soo-Jin Jeong),김우승(Woo-Seung Kim) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Conversion efficiency, durability and pressure drop of automotive exhaust catalysts are dependent on the flow distribution within the substrate. Conventional porous medium approach assuming monolith resistance based on one-dimensional laminar flow for simulating the flow through automotive exhaust catalysts overpredicts the flow uniformity in the monolith. In this study, additional pressure loss accounting for entrance effects due to oblique flow incident on the front face of monolith as a consequence of flow separation and recirculation within the diffuser is considered and incorporation of an additional pressure loss improves the predictions for the maximum flow velocity within the substrate. A numerical study of three-dimensional unsteady incompressible non-reacting flow inside various dual-monolith catalytic converters for the rapid acceleration/deceleration driving has also been conducted.
가솔린 엔진의 배출가스 저감을 위한 듀얼 모노리스형 촉매변환기의 형상 및 귀금속 촉매의 축방향 분포 최적화
김영득(Young-Deuk Kim),정수진(Soo-Jin Jeong),김우승(Woo-Seung Kim) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In practical applications, monolithic catalytic converters are operated at non-isothermal conditions. In this case, the active metal distribution along the length of the converter may influence its performance. Indeed, better conversions can be achieved by controlling the distribution of the same quantity of active material. In this study, a one-dimensional catalyst model has been adopted to predict the transient thermal and conversion characteristics of a dual monolithic catalytic converter with Platinum/Rhodium (Pt/Rh) catalysts. The optimal design of a longitudinal noble metal distribution of a fixed amount of catalyst is investigated to obtain the best performance of a dual monolithic catalytic converter by using a micro genetic algorithm with consideration of heat transfer, mass transfer, and chemical reaction in the monolith during FTP-75 cycle. The optimal axial distribution of the catalyst is determined by solving the multi-objective optimization problems which are to minimize both the CO cumulative emissions during FTP-75 cycle, and the difference between the integral value of a catalyst distribution function over the monolith volume and total catalytic surface area over total monolith volume. The parametric investigations for three cell densities of the front monolith are carried out by varying the volume ratio between front and rear monoliths with fixed volume and cell density of the rear monolith.
백금계 촉매상에서 산화질소(NO)의 산화 반응속도에 관한 실험 및 모델링 연구
김영득(Young-Deuk Kim),이정길(Jung-Gil Lee),심성민(Sung-Min Shim),박정권(Jung-Kwon Park),오세두(Se-Doo Oh),강정호(Jung-Ho Kang),정수진(Soo-Jin Jeong),김우승(Woo-Seung Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
To improve the NOx conversion over a SCR (selective catalytic reduction) catalyst, the DOC (diesel oxidation catalyst) is usually placed upstream of the SCR catalyst to enhance the fast SCR reaction (4NH₃+2NO+2NO₂→4N₂+6H₂O) using equimolar amounts of NO and NO₂. Here, a ratio of NO₂/NOx above 50% should be avoided, because the reaction with NO₂ only (4NH₃+4NO+O₂→4N₂+6H₂O) is slower than the standard SCR reaction (4NH₃+4NO+O₂→4N₂+6H₂O). In order to accurately predict the performance characteristics of SCR catalysts, it is therefore desired to develop a more simple and reliable mathematical and kinetic models on the oxidation kinetics of nitric oxide over a DOC. In the present work, the prediction accuracy and limit of three different chemical reaction kinetics models are presented to describe the chemicophysical characteristics and conversion performance of DOCs. Steady-state experiments with DOCs mounted on a light-duty four-cylinder 2.0-L turbocharged diesel engine then are performed, using an engine-dynamometer system to calibrate the kinetic parameters such as activation energies and pre-exponential factors of heterogeneous reactions. The reaction kinetics for NO oxidation over Pt-based catalysts is determined in conjunction with a transient one-dimensional (1D) heterogeneous plug-flow reactor (PFR) model with diesel exhaust gas temperatures in the range of 115-525℃ and space velocities in the range of (0.4-6.5)×10?h?¹.
바나듐계 촉매상에서 암모니아를 이용한 질소산화물의 환원반응속도에 수분이 미치는 영향에 관한 연구
김영득(Young-Deuk Kim),정희찬(Hee-Chan Jeong),심성민(Sung-Min Shim),정수진(Soo-Jin Jeong),김우승(Woo-Seung Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
The main and side reactions of the three selective catalytic reduction (SCR) reactions with ammonia over a vanadium-based catalyst have been investigated using synthetic gas mixtures in the 170-590℃ T-range. The three SCR reactions are standard SCR with pure NO, fast SCR with an equimolar mixture of NO and NO₂, and NO₂ SCR with pure NO₂. The selective catalytic oxidation of ammonia and the formation of nitrous oxide compete with the SCR reactions at the high temperatures. Water strongly inhibits the selective catalytic oxidation of ammonia and the formation of nitrous oxide, thus increasing the selectivity of the SCR reactions. However, the presence of water inhibits the SCR activity, most pronounced at low temperatures. In this study, the experimental results are analyzed by means of a dynamic 1D isothermal heterogeneous plug-flow reactor (PFR) model according to the Eley-Rideal mechanism.