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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society of Mechanical Engineers B
Journal Basic Information
Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 31, Issue 12 - Dec 2007
Volume 31, Issue 11 - Nov 2007
Volume 31, Issue 10 - Oct 2007
Volume 31, Issue 9 - Sep 2007
Volume 31, Issue 8 - Aug 2007
Volume 31, Issue 7 - Jul 2007
Volume 31, Issue 6 - Jun 2007
Volume 31, Issue 5 - May 2007
Volume 31, Issue 4 - Apr 2007
Volume 31, Issue 3 - Mar 2007
Volume 31, Issue 2 - Feb 2007
Volume 31, Issue 1 - Jan 2007
Selecting the target year
A Study on the Effect of Recirculated Exhaust Gas upon Exhaust Emissions of Boiler with a FGR System
Jung, Kwang-Ho ; Cho, Yong-Soo ; Bae, Myung-Whan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 405~415
DOI : 10.3795/KSME-B.2007.31.5.405
The effects of recirculated exhaust gas on exhaust emissions under four kinds of nozzle tip with the different fuel consumption rates are experimentally investigated by using an once-through boiler with a FGR system. The purpose of this study is to develop the FGR control system for reducing
emissions in boilers. Intake and exhaust oxygen concentrations, and equivalence ratio are considered to figure out the effect of FGR rate on exhaust emissions at various fuel consumption rates. It is found that
emissions are markedly decreased, while soot emissions are increased owing to the drop of intake and exhaust oxygen concentrations, and the rise of equivalence ratio as FGR rates are elevated. One can also conclude that the reduction in
emissions is more considerably influenced by the variation of equivalence ratio due to the FGR rate than the fuel consumption rate.
Flow Characteristics and Residence Time of Activated Carbon in the Cyclone for Optimized Design of an Adsorption/Catalysis Reactor
Choi, Choeng-Ryul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 416~424
DOI : 10.3795/KSME-B.2007.31.5.416
In adsorption/catalytic process, numerical analysis has been performed to identify the flow characteristics of flue gas in the cyclone and to estimate the residence time of activated carbon using Computational Fluid Dynamics (CFD) technique. To consider flue gas and activated carbon particles simultaneously, Euler-Lagrangian model was employed so that residence time could be obtained from the numerical analysis directly. The numerical analysis has been performed with different three particle sizes and compared each flow characteristics with particle’ size. Fundamental flow patterns of flue gas and activated carbon particles, pressure distribution, residence time of flue gas, and activated carbon particles and distribution of activated carbon have been obtained from the numerical analysis.
Flow Characteristics with Inflow-Duct Types in the Reactor of an Integrated Adsorption/Catalysis Process with Bag Filters
Choi, Choeng-Ryul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 425~434
DOI : 10.3795/KSME-B.2007.31.5.425
An integrated adsorption/catalytic process has been considered to treat dioxin and
simultaneously. The process consists of a cyclone and a reactor with nine bag filters. In this study, numerical analysis has been performed to understand flow characteristics with inflow-duct types in the reactor. To consider flue gas and activated carbon particles simultaneously, Euler-Lagrangian model was employed. Fundamental flow patterns of flue gas and activated carbon particles, pressure distribution and distribution of activated carbon have been obtained from the numerical analysis. Also trace length and residence time of flue gas, residence time of activated carbon particles have been calculated directly. Flow patterns of flue gas and activated carbon particles in the reactor were very complicated and they moved along very various paths. Therefore, their residence time in the reactor was also various. The flow characteristics in the reactor were strongly influenced by inflow-duct types. The results obtained would be effectively used to estimate the removal efficiency in the reactor once the residence time is combined with the reaction equation.
A Study on the Phase Criteria of Nanoscale Systems
Lim, Min-Jong ; Choi, Gyung-Min ; Kim, Duck-Jool ; Chung, Han-Shik ; Jeong, Hyo-Min ; Choi, Soon-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 435~447
DOI : 10.3795/KSME-B.2007.31.5.435
Recently, as MEMS and NEMS devices have been widely used in the various engineering applications, the characteristics of nanoscale systems are investigated in the limelight. However, as opposed to a macroscale system, the identification of the state of nanoscale systems is extremely hard because they can include only the order of
molecules, which requires highly expensive and accurate experimental apparatus for an investigation. This limitations make the study on nanoscale system use computer simulations. Therefore, it is strongly required to identify the state of nanoscale system simulated in computer simulation. In this molecular dynamics(MD) study, we suggest that the potential energy of individual molecule can be used as criterion for defining the state of clusters or nanoscale systems. In addition, we compared the phase state from the potential energy with one from the radial distribution function(RDF) for verification. The comparison showed that the intermolecular potential energy can be used as a criteria distinguishing the phase state of nanoscale systems.
Design Parametric Analysis of PEM Fuel Cell and Hybrid Systems
You, Byung-June ; Lee, Young-Duk ; Ahn, Kook-Young ; Kim, Tong-Seop ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 448~456
DOI : 10.3795/KSME-B.2007.31.5.448
Performance of PEM fuel cell systems and hybrid systems combining a PEMFC with a gas turbine have been evaluated. Two different reforming methods(steam reforming and autothermal reforming) were considered. Performances of fuel cell systems with two reforming methods were compared and effects of various design parameters on the system performance were investigated. Configurations of PEM fuel cell systems with two reforming methods have been revised to accommodate a gas turbine, resulting in PEMFC/GT hybrid systems. Performance of the hybrid systems were analyzed and compared with those of PEM systems. Influences of major design parameters on the hybrid system performance were also investigated.
Evaluation and Prediction of Cleanliness Level in the Mini-Environment System Using Local Mean Air-Age
Noh, Kwang-Chul ; Lee, Hyeon-Cheol ; Park, Jung-Il ; Oh, Myung-Do ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 457~466
DOI : 10.3795/KSME-B.2007.31.5.457
A numerical and experimental study on the evaluation and the prediction of cleanliness level in the mini-environment system was carried out. Using the concept of local mean air-age (LMA) and effective flow rate, the new direct method for estimating the mini-environment was developed and compared with the previous performance index of airflow pattern characteristics. It was found out that the airflow pattern analysis is a restricted method to estimate the real performance of the mini-environment. The reason is that the airflow pattern cannot predict the effect of the increment of the ventilation rate on the cleanliness level in the mini-environment. While LMA is capable of showing the effects of the contaminant accumulation caused by turbulent intensity, eddy, and the increment of the effective flow rate. This result showed that LMA is more exact and effective performance index than the previous one like the airflow pattern characteristics.
A Study of the Behavior of Liquid Phase Spray Considering Critical Condition of the Fuel
Park, Jong-Sang ; Kim, Si-Pom ; Chung, Sung-Sik ; Ha, Jong-Yul ; Yeom, Jeong-Kuk ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 467~472
DOI : 10.3795/KSME-B.2007.31.5.467
In this study the penetration distance of liquid phase fuel(i.e. liquid phsae length) was investigated in evaporative field. An exciplex fluorescence method was applied to the evaporative fuel spray to measure and investigate both the liquid and the vapor phase of the injected spray. For accurate investigation, images of the liquid and vapor phase regions were recorded using a 35mm still camera and CCD camera, respectively. Liquid fuel was injected from a single-hole nozzle (l/d=1.0mm/0.2mm) into a constant-volume chamber under high pressure and temperature in order to visualize the spray phenomena. Experimental results indicate that the liquid phase length decreased down to a certain constant value in accordance with increase in the ambient gas density and temperature. The constant value, about 40mm in this study the, is reached when the ambient density and temperature of the used fuel exceed critical condition.
A Study on the Suppression of Carbon Deposition in Solid Oxide Fuel Cells Through Methane Internal Reforming
Kang, Yun-Hyeok ; Lim, Sung-Kwang ; Yoo, Yung-Sung ; Park, Jin-Woo ; Bae, Joong-Myeon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 473~481
DOI : 10.3795/KSME-B.2007.31.5.473
Compared to other types of fuel cells, SOFC has advantages like a wide output range and the direct use of hydrocarbon fuel without the process of external reforming. Particularly because the direct use of fuel without reforming reaction is closely linked to overall system efficiency, it is a very attractive advantage. We tried the operation with methane. However, although methane has a small number of carbons compared to other hydrocarbon fuels, our experiment found the deposition of carbon on the surface of the SOFC electrode. To overcome the problem, we tried the operation through activating internal reforming. The reason that internal reforming was possible was that SOFC runs at high temperature compared to other fuel cells and its electrode is made of Ni, which functions as a catalyst favorable for steam reforming.
1-D Two-phase Flow Investigation for External Reactor Vessel Cooling
Kim, Jae-Cheol ; Park, Rae-Joon ; Cho, Young-Rho ; Kim, Sang-Baik ; Kim, Sin ; Ha, Kwang-Soon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 482~490
DOI : 10.3795/KSME-B.2007.31.5.482
When a molten corium is relocated in a lower head of a reactor vessel, the ERVC (External Reactor Vessel Cooling) system is actuated as coolant is supplied into a reactor cavity to remove a decay heat from the molten corium during a severe accident. To achieve this severe accident mitigation strategy, the two-phase natural circulation flow in the annular gap between the external reactor vessel and the insulation should be formed sufficiently by designing the coolant inlet/outlet area and gap size adequately on the insulation device. For this reason, one-dimensional natural circulation flow tests and the simple analysis were conducted to estimate the natural circulation flow under the ERVC condition of APR1400. The experimental facility is one-dimensional and scaled down as the half height and 1/238 channel area of the APR1400 reactor vessel. The calculated circulation flow rate was similar to experimental ones within about
15% error bounds and depended on the form loss due to the inlet/outlet area.
An Experimental Study on the Characteristics of Flame Stabilization in a Small Heat-Regenerative Combustor of Counter-Current Channels
Cho, Sang-Moon ; Kim, Nam-Il ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 5, 2007, Pages 491~498
DOI : 10.3795/KSME-B.2007.31.5.491
Flame characteristics of a methane-air premixed flame stabilized in a heat-regenerative small combustor were investigated experimentally. A small combustor having two counter-current shallow channels and a combustion space at one side was developed. In which the channel-gap was less the ordinary quenching distance of a stoichiometric methane-air premixed flame. Two design parameters of channel gap and thickness of the middle wall, which is located between two channels for unburned and burned gases, were varied. Flame stabilization conditions and characteristic flame behaviors were experimentally examined. Conclusively, Blowout conditions were governed mostly by the scale of the combustion space, and flashback conditions into the channel are dominated by the channel gap. Surface temperatures of the combustor were between 100 to 500
. Additionally, two distinctive flame stabilization modes of radiation and well-stirred?reaction were observed and their applicability was discussed.