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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
Editor in Chief :
Volume & Issues
Volume 36, Issue 12 - Dec 2012
Volume 36, Issue 11 - Nov 2012
Volume 36, Issue 10 - Oct 2012
Volume 36, Issue 9 - Sep 2012
Volume 36, Issue 8 - Aug 2012
Volume 36, Issue 7 - Jul 2012
Volume 36, Issue 6 - Jun 2012
Volume 36, Issue 5 - May 2012
Volume 36, Issue 4 - Apr 2012
Volume 36, Issue 3 - Mar 2012
Volume 36, Issue 2 - Feb 2012
Volume 36, Issue 1 - Jan 2012
Selecting the target year
An Experimental Study of Fuel Economy and Emission Characteristics for a Heavy-Duty DME Bus
Oh, Yong-Il ; Pyo, Young-Duk ; Kwon, Ock-Bae ; Beak, Young-Sun ; Cho, Sang-Hyun ; Lim, Ock-Taeck ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 371~376
DOI : 10.3795/KSME-B.2012.36.4.371
The experimental test was conducted for a heavy-duty DME bus in JE-05 exhaust gas test mode using a chassis dynamometer, exhaust gas analyzers, and a PM measurement system. The heavy-duty DME bus was not equipped with after-treatment systems such as DOC or DPF. The dynamic behavior, emission characteristics, and fuel economy of the bus were investigated with an 8.0-liter, 6-cylinder conventional diesel engine. The results showed that the dynamic behavior in DME mode was almost the same as in diesel mode. However, there was little difference among the two operation modes for
and CO emissions. THC emissions were lower for DME mode than for diesel mode. Also, the amount of PM emissions was remarkably lower than for the diesel mode because DME contains a greater amount of oxygen than diesel. The data showed that
emissions were almost similar in the two modes but fuel economy (calculated using heating value) was lower for DME mode than for diesel mode.
Analysis of Temperature Distribution and Heat Loss for an Asymmetric Trapezoidal Fin
Kang, Hyung-Suk ; Song, Nyeon-Joo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 377~383
DOI : 10.3795/KSME-B.2012.36.4.377
The temperature distribution of an asymmetric trapezoidal fin with various upper lateral surface slopes is investigated by using the two-dimensional analytic method. For this asymmetric fin, convection from the inner fluid to the inner wall, conduction from the inner wall to the fin base and conduction through the fin base are considered simultaneously. The temperature profile with the variation of dimensionless fin length and height coordinates is shown. Also, the temperature variation at the bottom tip of the fin is presented as a function of the fin shape factor. Heat losses through the fin base and from each side are compared for variations in fin length. One of the results shows that temperature at the fin bottom tip decreases linearly as the fin shape factor increases.
Thermal Analysis of a Radial Heat Sink with Radiation and Natural Convection
Yu, Seung-Hwan ; Jang, Dae-Seok ; Lee, Kwan-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 385~390
DOI : 10.3795/KSME-B.2012.36.4.385
A radial heat sink, adopted to LED(light emitting diode) downlight, was optimized. Discrete transfer radiation model (DTRM) was used to calculate radiation heat transfer, and numerical model was verified with experimental results. The effects of number of fin, long fin length and middle fin length on overall thermal resistance and radiation heat transfer were analyzed. As the emissivity increased, thermal resistance decreased due to the increment of radiation heat transfer. The radial heat sink was optimized and optimum number of long fins is 19~28, optimum length of long fin is about half of radius of heat fink and optimum fin ratio is 0.4~0.7.
A Continuous Cell Separator Based on Gravity and Buoyant Forces in Fluids of Dissimilar Density
Oh, Ae-Gyoung ; Lee, Dong-Woo ; Cho, Young-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 391~395
DOI : 10.3795/KSME-B.2012.36.4.391
We present a continuous cell separator that achieves density-dependent and size-independent cell separation based on the net force of gravity and buoyancy forces on the cells in dissimilar density fluids. Previous cell separators are, based on the size or dielectrophoretic property of the cells and, are suitable for size-dependent and density-independent cell separation. However, these properties can make it difficult to collect the same types of cells with the same density but with size variations. The present separator, however, is capable of collecting the same types of cells based on the cell density in the fluid. Regardless of cell size, the proposed chip isolates low density cells, (white blood cells, or WBCs) at the upper outlet while obtaining high-density cells (red blood cells, or RBCs) from the lower outlet based on density. Efficiency levels for separation of WBCs and RBCs were
, respectively. The present separator therefore has the potential for use in the pretreatment of whole blood.
Numerical Study of the Flow Characteristics in a Diesel Exhaust System with a Vane-Type Static Mixer
Kang, Kyoung-Nam ; Lee, Jee-Keun ; Kim, Man-Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 397~404
DOI : 10.3795/KSME-B.2012.36.4.397
In this research, a numerical study was carried out on the mixing and flow characteristics of a vane-type static mixer for the reduction of
in the SCR systems from the diesel exhaust environments. The mixer was located at a distance of 57 times the pipe diameter away from the inlet. The analyses were performed by changing various parameters such as vane angles, blockage ratio, and location of the vane. Flow characteristics through the mixer were characterized by the uniformity index, swirl number, and pressure drop. The results show that uniformity index, pressure coefficient and swirl number are substantially influenced by the vane angle, blockage ratio and position of the vane of the mixer. In particular, the swirl number was increased when the vane was located near the pipe wall, or the vane angle was increased or scale was extended.
An Experimental Study on the Combustion Characteristics of a Catalytic Combustor for an MCFC Power Generation System
Hong, Dong-Jin ; Ahn, Kook-Young ; Kim, Man-Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 405~412
DOI : 10.3795/KSME-B.2012.36.4.405
In the MCFC power generation system, the combustor supplies a high temperature mixture of gases to the cathode and heat to the reformer by using the off-gas from the anode; the off-gas includes high concentrations of
. Since a combustor needs to be operated in a very lean condition and avoid local heating, a catalytic combustor is usually adopted. Catalytic combustion is also generally accepted as one of the environmentally preferred alternatives for generation of heat and power from fossil fuels because of its complete combustion and low emissions of pollutants such as CO, UHC, and
. In this study, experiments were conducted on catalytic combustion behavior in the presence of Pd-based catalysts for the BOP (Balance Of Plant) of 5 kW MCFC (Molten Carbonate Fuel Cell) power generation systems. Extensive investigations were carried out on the catalyst performance with the gaseous
fuel by changing such various parameters as
addition, inlet temperature, excess air ratio, space velocity, catalyst type, and start-up schedule of the pilot system adopted in the BOP.
Combustion Characteristics of a VIStA Burner Dividing Flame in a Once-Through Type Boiler
Ahn, Joon ; Kim, Hyouck-Ju ; Choi, Kyu-Sung ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 413~418
DOI : 10.3795/KSME-B.2012.36.4.413
A modified VIStA (Vortex Inertial Staged Air) burner has been developed and applied to a once-through type boiler. The secondary air is supplied through a swirler instead of nozzles, which stabilizes the flame and reduces carbon monoxide (CO) emissions. However, the modification increases the emission of nitrogen oxides (NOx). To balance emissions of the two pollutants, a divided flame was adopted. An air damper was installed to control the distribution of air to each combustion chamber, and three types of flame dividers were studied. The effects of the air-fuel ratio and combustion load on the NOx formation were investigated. The divided flame was found to reduce the NOx emission up to 25%, while keeping the CO to less than 10 ppm.
The Effect of Inferior Turbinectomy on Heat/Humidity Transfer Ability of the Nose
Chung, Kang-Soo ; Chang, Ji-Won ; Kim, Sung-Kyun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 419~424
DOI : 10.3795/KSME-B.2012.36.4.419
In addition to respiration, the nose performs three other major physiological functions-air-conditioning, filtering, and smelling. On the basis of our experience in experimental investigations of nasal airflows in normal and abnormal nasal cavity models, airflows in the normal model and three artificially deformed models, which simulate the results of surgical treatments (inferior turbinectomy), are investigated by PIV and CFD. The left cavities of all three models are normal, and the right cavities are modified as follows: (1) excision of the head of the inferior turbinate, (2) resection of the lower fifth of the inferior turbinate, and (3) resection of almost the entire inferior turbinate. The use of high-resolution CT data and careful surface rendering of three-dimensional computer models with the help of an ENT doctor provide more sophisticated nasal cavity models. Nasal airflows for both normal and deformed cases are also compared.
Numerical Analysis of Heat Transfer and Fuel Conversion for MCFC Preconverter
Byun, Do-Hyun ; Sohn, Chang-Hyun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 425~430
DOI : 10.3795/KSME-B.2012.36.4.425
In this study, a preconverter of an MCFC for an emergency electric power supplier is numerically simulated to increase the hydrogen production from natural gas (methane). A commercial code is used to simulate a porous catalyst with a user subroutine to model three dominant chemical reactions-steam reforming, water-gas shift, and direct steam reforming. To achieve a fuel conversion rate of 10% in the preconverter, the required external heat flux is supplied from the outer wall of the preconverter. The calculated results show that the temperature distribution and chemical reaction are extremely nonuniform near the wall of the preconverter. These phenomena can be explained by the low heat conductivity of the porous catalyst and the endothermic reforming reaction. The calculated results indicate that the use of a compact-size preconverter makes the chemical reaction more uniform and provides many advantages for catalyst maintenance.
Viscoelastic Behavior of High Density Polyethylene Using High Tibial Osteotomy with Respect to the Strain Rate
Hwang, Jung-Hoon ; Kim, Cheol-Woong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 431~438
DOI : 10.3795/KSME-B.2012.36.4.431
The mechanical behavior of the polymeric material, HDPE depends on both time and temperature. The study of the tensile behavior at different strain rates is important in engineering design of the orthopedics device such as X-band plate. The mechanical properties and deformation mechanisms of HDPE are strongly dependent on the applied strain rate. Generally, the deformation behavior of HDPE based on the stress-strain curve is complex because of the highly inhomogeneous nature of plastic deformation, particularly that of necking. Therefore, we attempted to determine the mechanical behavior of HDPE in this study. Normally, tensile testing under various strain rates of the HDPE has been used to determine the mechanical behavior. We performed tensile tests at various strain rates (1 to 500 %/min) to analyze the viscoelastic behavior on increasing the strain rate. A tensile stress-strain curve was plotted from the data, and the point of transition was marked to calculate the transition stress, strain, and modulus.
Influence of Gas Turbine Performance and Fuel Cell Power Share on the Performance of Solid Oxide Fuel Cell/Gas Turbine Hybrid Systems
Ahn, Ji-Ho ; Kang, Soo-Young ; Kim, Tong-Seop ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 439~447
DOI : 10.3795/KSME-B.2012.36.4.439
Solid oxide fuel cell/gas turbine hybrid systems that use three gas turbines having different power outputs were devised and their performance was compared. The power shares of the gas turbine and fuel cell and the net system efficiency were compared among the three systems, and their variations with the design fuel cell temperature were investigated. The system efficiency was predicted to be insensitive to the fuel cell temperature in the sub-MW system, but it increased with increasing fuel cell temperature in both the multi-MW and hundred-MW systems. The influence of air bypass around the fuel cell on the system performance was also investigated.
A Numerical Study on the Factors of the Flow Hunting in a Orifice Meter
Shin, Chang-Hoon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 449~455
DOI : 10.3795/KSME-B.2012.36.4.449
During the measurement of the flow rate of gases such as natural gas, flow hunting is observed in most orifice meters but the intensity of flow hunting at each metering system shows different characteristics. In order to investigate why such a difference occurs and whether the difference actually influences metering error, pipeline network analysis on the main factors and characteristics of flow hunting was carried out in a previous study. Following this, in this study, computational fluid dynamics (CFD) analysis was carried out to clarify the relation between flow instability and flow hunting and determine the factors influencing the orifice meter depending on the intensity of upward pressure fluctuation, time interval, and flow rate. Finally, we showed that the pressure hunting rate is a function of the ratio of the pressure difference before and after an orifice meter. On the basis of CFD analysis results, we also presented some major factors and relations influencing flow hunting.
A Study on the Design Parameters of a Gasket and Innercase of a Refrigerator to Reduce Dew Generation on the Outer Surface
Kang, Seok-Hoon ; Kim, Seong-Jin ; Kim, Ju-Hwan ; Min, June-Kee ; Sohn, Chang-Min ; Park, Sang-Hu ;
Transactions of the Korean Society of Mechanical Engineers B, volume 36, issue 4, 2012, Pages 457~463
DOI : 10.3795/KSME-B.2012.36.4.457
Current refrigerators are designed to have thin doors and walls to facilitate user convenience and increase inner storage space. However, the thin doors and walls gives rise to the problem of dew generation on the outer surface of a refrigerator due to a large critical temperature difference between the outer wall and the room air; So far, an electric heater is commonly used for making the dew to evaporate; in this case, the heater inevitably requires additional electrical power. We propose a new approach to reduce the dew generation in a refrigerator by redesigning the gasket and varying the thickness of the inner case of the refrigerator. The results of simulations performed in this study indicate that the surface temperature in the region where dew was generated was increased by approximately
without the use of a heater.