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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 32, Issue 12 - Dec 2008
Volume 32, Issue 11 - Nov 2008
Volume 32, Issue 10 - Oct 2008
Volume 32, Issue 9 - Sep 2008
Volume 32, Issue 8 - Aug 2008
Volume 32, Issue 7 - Jul 2008
Volume 32, Issue 6 - Jun 2008
Volume 32, Issue 5 - May 2008
Volume 32, Issue 4 - Apr 2008
Volume 32, Issue 3 - Mar 2008
Volume 32, Issue 2 - Feb 2008
Volume 32, Issue 1 - Jan 2008
Selecting the target year
Pin Fin Optimization Based on the Ratio of Heat Loss to the Maximum Heat Loss
Kang, Hyung-Suk ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 817~823
DOI : 10.3795/KSME-B.2008.32.11.817
A pin fin with variable fin base thickness is optimized based on the ratio of heat loss to the maximum heat loss using a two-dimensional analytic method. The temperature profile along the normalized radius position in the fin is presented. For fixed fin outer radius, the optimum heat loss, fin length and efficiency as a function of fin base thickness, outer radius, convection characteristic numbers ratio and ambient convection characteristic number are presented. One of the results shows that the effect of fin outer radius and ambient convection characteristic number on the optimum fin length is remarkable.
A Continuous Particle-size Sorter Using Negative a Dielectrophoretic Virtual Pillar Array
Chang, Sung-Hwan ; Cho, Young-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 824~831
DOI : 10.3795/KSME-B.2008.32.11.824
We present a continuous size-dependent particle separator using a negative dielectrophoretic (DEP) virtual pillar array. Two major problems in the previous size-dependent particle separators include the particle clogging in the mechanical sieving structures and the fixed range of separable particle sizes. The present particle separator uses the virtual pillar array generated by negative DEP force instead of the mechanical pillar array, thus eliminating the clogging problems. It is also possible to adjust the size of separable particles since the size of virtual pillars is a function of a particle diameter and applied voltage. At an applied voltage of 500 kHz
(root mean sqaure voltage) sinusidal wave and a flow rate of
, we separate
-diameter polystyrene (PS) beads with separation purity of 95%, 92%, 50%, and 63%, respectively. The
-diameter PS beads have relatively low separation purity of 50% and 63%. However, at an applied voltage of
, we separate
-diameter PS beads with separation purity over 99%. Therefore, the present particle separator achieves clog-free size-dependent particle separation, which is capable of size tuning of separable particles.
High Power Laser Driven Shock Compression of Metals and Its Innovative Applications
Lee, Hyun-Hee ; Gwak, Min-Cheol ; Choi, Ji-Hee ; Yoh, Jai-Ick ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 832~840
DOI : 10.3795/KSME-B.2008.32.11.832
Ablation occurs at irradiance beyond
with nanosecond and short laser pulses focused onto any materials. Phenomenologically, the surface temperature is instantaneously heated past its vaporization temperature. Before the surface layer is able to vaporize, underlying material will reach its vaporization temperature. Temperature and pressure of the underlying material are raised beyond their critical values, causing the surface to explode. The pressure over the irradiated surface from the recoil of vaporized material can be as high as
. The interaction of high power nanosecond laser with a thin metal in air has been investigated. The nanosecond pulse laser beam in atmosphere generates intensive explosions of the materials. The explosive ejection of materials make the surrounding gas compressed, which form a shock wave that travels at several thousand meters per second. To understand the laser ablation mechanism including the heating and ionization of the metal after lasing, the temporal evolution of shock waves is captured on an ICCD camera through laser flash shadowgraphy. The expansion of shock wave in atmosphere was found to agree with the Sedov's self-similar spherical blast wave solution.
Measurement and Calculation of Bulk Modulus for DME
Cho, Seung-Hwan ; Lee, Beom-Ho ; Lee, Dae-Yup ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 841~848
DOI : 10.3795/KSME-B.2008.32.11.841
DME(Di-methyl Ether) has been expected to be one of the promising alternative fuels for compression ignition engines due to its low emission characteristics for particulate matter. However, its physical properties such as density, bulk modulus and viscosity are not comparable to those of conventional diesel fuel. Especially, problems caused by low lubricity and high compressibility need to be understood more thoroughly, when a DME fuel is used for compression ignition engine, especially with mechanical fuel supply system. In this study, measurement and calculation of DME's bulk modulus were carried out over the range of temperatures from
, and pressures from 50 bar to 250 bar using an experimental apparatus built in this work. The results show that DME is prone to be compressed more easily compared to diesel fuel. A comparison of bulk modulus with butane and propane were also made in this work.
Analysis of Part Load Performance of a Hybrid PEMFC System
Ji, Seung-Won ; You, Byung-June ; Kim, Tong-Seop ; Sohn, Jeong-Lak ; Lee, Young-Duk ; Ahn, Kook-Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 849~855
DOI : 10.3795/KSME-B.2008.32.11.849
The paper addresses modeling and analysis of the part load performance of a hybrid fuel cell system integrating a polymer electrolyte membrane fuel cell(PEMFC) and a gas turbine(GT). The system is a pressurized one where the working pressure of the PEMFC is higher than the ambient pressure. In addition to the two major components, the system also includes auxiliary parts such as a steam reformer, a humidifier, and afterburner and so on. Based on design analysis, component off-design models are incorporated in the analysis program and part load operation is simulated. The mode for the part load operation of the PEMFC/GT hybrid system is a variable rotational speed operation. The operating characteristics and variations in the system efficiency and component performance parameters at part load are analyzed.
Magnetophoretic Microseparators for Separating Blood Cells Based on Their Native Magnetic Properties
Jung, Jin-Hee ; Han, Ki-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 856~862
DOI : 10.3795/KSME-B.2008.32.11.856
This paper presents the characterization of a continuous magnetophoretic microseparator for separating white and red blood cells from peripheral whole blood cells based on their native magnetic properties. The magnetophoretic microseparator separated the blood cells using a high gradient magnetic separation (HGMS) method without the use of additives such as magnetic beads or probing materials. Experimental results show that the paramagnetic capture mode microseparator can continuously separate out 93.5% of red blood cells and 97.4% of white blood cells from diluted whole blood, and the diamagnetic capture mode microseparator can continuously separate out 89.7% of red blood cells and 72.7 % of white blood cells by using applying an external magnetic flux of 0.2 T using a permanent magnet.
Application of the New Calibration Algorithm of a Straight-Type Five-Hole Pressure Probe
Kim, Jang-Kweon ; Oh, Seok-Hyung ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 863~869
DOI : 10.3795/KSME-B.2008.32.11.863
This paper investigated the new calibration algorithm of a straight-type five-hole pressure probe for measuring three-dimensional flow velocity components. This new calibration algorithm was used for velocity data reduction from the calibration map and based on the combination of a look-up, a binary search algorithm and a geometry transformation including the translation and reflection of nodes in a calibration map. The calibration map was expanded up to the application angle,
of a probe. This velocity data reduction method showed a perfect performance without any kind of interpolating errors in calculating yaw and pitch angles from the calibration map. Moreover, when it was applied to an actual flow field including a swirling flow, a good result came out on the whole.
A Study on the Modeling of Pt-Catalyzed Reaction and the Characteristics of Mass Transfer in a Micro-Scale Combustor
Lee, Gwang-Goo ; Suzuki, Yuji ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 870~877
DOI : 10.3795/KSME-B.2008.32.11.870
Numerical analysis is applied to model Pt-catalyzed reaction in a micro-scale combustor fueled by butane. The reaction constants of catalytic oxidation are determined from plug flow model with the experimental data. Orders of magnitude between the chemical reaction rate and the mass transfer rate are carefully compared to reveal which mechanism plays a dominant role in the total fuel conversion rate. For various conditions of fuel flow rate and surface temperature, the profiles of Sherwood number are investigated to study the characteristics of the mass transport phenomena in the micro-tube combustor.
Experimental Study on Spray Structure of a High Pressure 6-Hole Injector by Mie Scattering Technique
Kim, Seong-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 878~883
DOI : 10.3795/KSME-B.2008.32.11.878
The spray characteristics of a high pressure 6-hole injector were examined in a single cylinder optical direct injection spark ignition (DISI) engine. The effects of injection timing, in-cylinder charge motion, fuel injection pressure and coolant temperature were investigated using the 2-dimensional Mie scattering technique. It was confirmed that the in-cylinder charge motion played a major role in the fuel spray distribution during the induction stroke while the propagation of fuel spray was restrained during the compression stroke by the increasing pressure and the upward moving piston. In additions, it was confirmed that the liquid fuel droplets existing at the sprays edges were vaporized by the increase of the coolant temperature.
An Experimental Study on the Performance and Emission Characteristics of SI Engine Using New Type of Throttle Body
Cho, Seung-Wan ; Lee, Sang-Suk ; Jin, Dong-Kyu ; Shim, Jae-Joon ; Kim, Gyu-Bo ; Jeon, Chung-Hwan ; Chang, Young-June ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 884~890
DOI : 10.3795/KSME-B.2008.32.11.884
Many researches have been carried out to reduce the emission levels and lower the fuel consumption in SI engines. Recently electronically controlled injection system is widely adapted to a passenger car to achieve these goals. Throttle body is also an important factor which influences on the emissions and engine power. In this study we redesigned a throttle body and conducted an experimental study to see the effects on engine performance and emission characteristics. We could find that idle speed control(ISC) showed stable operation characteristics as the cooling water temperature varied. And CO and HC emissions also satisfied the regulation limit.
Numerical Study of Pulsatile Blood Flow in Stenotic Artery
Seo, Tae-Won ; Buriev, Bahtiyor ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 891~896
DOI : 10.3795/KSME-B.2008.32.11.891
In the present computational study, simple stenotic artery models using pulsatile flow condition were investigated. A 1 Hz non-reversing sinusoidal velocity for pulsatile flow was imposed at the flow inlet and the corresponding Womersley number based on the vessel radius is 2.75. The simple stenotic geometries have been used that consist of 25%, 50% and 75% semicircular constriction in a cylindrical tube. In this paper, numerical solutions are presented for a first harmonic oscillatory flow using commercial software ADINA 8.4. As stenosis and Reynolds number increase, the maximum wall shear stress(WSS) increases while the minimum WSS decreases. As the stenotic rate increases, the pressure drop at the throat severely decreases to collapse the artery and plaque. It is found that the fluid mechanical disturbances due to the constriction were highly sensitive with rate of stenosis and Reynolds number. When Reynolds number and stenosis increase, the larger recirculation region exists. In this recirculation region the possibility of plaque attachment is increasingly higher. The present results enhance our understanding of the hemodynamics of a stenotic artery.
A Study on Numerical Modeling of the Induced Heat to Gaseous Flow inside the Mixing Area of Ammonia SCR System in Diesel No
Bae, Myung-Whan ; Syaiful, Syaiful ;
Transactions of the Korean Society of Mechanical Engineers B, volume 32, issue 11, 2008, Pages 897~905
DOI : 10.3795/KSME-B.2008.32.11.897
Selective catalytic reduction(SCR) is known as one of promising methods for reducing
emissions in diesel exhaust gases.
emissions react with ammonia in the catalyst surface of SCR system at working temperature of catalyst. In this study, to raise the reacting temperature when the exhaust gas temperature is too low, a heater is located at the bottom of SCR reactor. At an ambient temperature, ammonia is radially injected perpendicular to the exhaust gas flow at inlet pipe and uniformly mixed in the mixing area after being impinged against the wall. To predict the turbulent model inside the mixing area of SCR system, the standard
model is applied. This work investigates numerically the effects of induced heat on the gaseous flow. The results show that the Taylor-
type vortex is generated after the gaseous flow impinges the wall in which these vortices influence the temperature distribution. The addition of heat disturbs the flow structure in bottom area and then stretching flow occurs. Vorticity strand is also formed when heat is continuously increased. Constriction process takes place, however, when a further heat input over a critical temperature is increased and finally forms shed vortex which is disconnected from the vorticity strand. The strong vortex restricts the heat transport in the gaseous flow.