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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
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Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 35, Issue 12 - Dec 2011
Volume 35, Issue 11 - Nov 2011
Volume 35, Issue 10 - Oct 2011
Volume 35, Issue 9 - Sep 2011
Volume 35, Issue 8 - Aug 2011
Volume 35, Issue 7 - Jul 2011
Volume 35, Issue 6 - Jun 2011
Volume 35, Issue 5 - May 2011
Volume 35, Issue 4 - Apr 2011
Volume 35, Issue 3 - Mar 2011
Volume 35, Issue 2 - Feb 2011
Volume 35, Issue 1 - Jan 2011
Selecting the target year
Adhesion Characteristics of Polymer Material Treated by Atmospheric Pressure Plasma
Seo, Seung-Ho ; Chang, Sung-Hwan ; Yoo, Yeoung-Een ; Chung, Jae-Dong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 445~450
DOI : 10.3795/KSME-B.2011.35.5.445
We studied the adhesion characteristics of polymer films (PC, PET, EVA) treated by atmospheric pressure plasma. The process parameters were the frequency, gas flow, and treatment time; we studied the effects of these parameters on the adhesion characteristics of the polymer materials. We used de-ionized water and diiodomethane as the polar and nonpolar solvents, respectively, for measuring the contact angles, and subsequently calculated the surface free energy of each polymer film. The adhesion characteristics were studied by carrying out a
peel-off test. The polymer films treated with plasma developed a hydrophilic surface, which led to increased surface free energy and improved adhesion properties. From the results for contact angle, surface free energy, and adhesion strength, we obtained the optimal plasma-treatment conditions.
Observation of Ignition Characteristics of Coals with Different Moisture Content in Laminar Flow Reactor
Kim, Jae-Dong ; Jung, Sung-Jae ; Kim, Gyu-Bo ; Chang, Young-June ; Song, Ju-Hun ; Jeon, Chung-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 451~457
DOI : 10.3795/KSME-B.2011.35.5.451
The main objective of this study is to investigate the variation in the ignition characteristics of coals as a function of moisture content in a laminar flow reactor (LFR) equipped with a fuel moisture micro-supplier designed by the Pusan Clean Coal Center. The volatile ignition position and time were observed experimentally when a pulverized coal with moisture was fed into the LFR under burning conditions similar to those at the exit of the pulverizer and real boiler. The reaction-zone temperature along the centerline of the reactor was measured with a
, R-type thermocouple. For different moisture contents, the volatile ignition position was determined based on an average of 15 to 20 images captured by a CCD camera using a proprietary image-processing technique. The reaction zone decreased proportionally as a function of the moisture content. As the moisture content increased, the volatile ignition positions were 2.92, 3.36, 3.96, and 4.65 mm corresponding to ignition times of 1.46, 1.68, 2.00, and 2.33 ms, respectively. These results indicate that the ignition position and time increased exponentially. We also calculated the ignition-delay time derived from the adiabatic thermal explosion. It showed a trend that was similar to that of the experimental data.
Experimental Study of Process Chiller for Semiconductor Temperature Control
Cha, Dong-An ; Kwon, Oh-Kyung ; Oh, Myung-Do ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 459~465
DOI : 10.3795/KSME-B.2011.35.5.459
Excessive heat may be generated during the semiconductor manufacturing process. Therefore, precise control of temperature is required to maintain a constant ambient temperature and wafer temperature in the chamber. Compared to an industrial chiller, a semiconductor chiller's power consumption is high because it is in continuous operation for a year. Because of this high power consumption, it is necessary to develop an energy-efficient chiller by optimizing the operation. The competitiveness of domestic products is low because of the high energy consumption. We experimentally investigated a domestic semiconductor by conducting load change, temperature rise and fall, and control precision experiments. The experimental study showed that the chiller had 2.1-3.9 kW of cooling capacity and 0.56-0.93 of EER. The control precisions were
when the setting temperatures were
Heat Transfer from Rectangular Fins with a Circular Base
Yu, Seung-Hwan ; Lee, Kwan-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 467~472
DOI : 10.3795/KSME-B.2011.35.5.467
The heat transfer over a radial heat sink, adapted for LED (light emitting diode) downlights, was experimentally and analytically investigated. We added radiation heat transfer into a previous calculation that neglected this factor. The numerical results agreed well with experimental results. Parametric studies were performed to compare the effects of the geometric parameters (fin length, fin height, ideal number of fins) and the operating parameter (heat flux) on the average heat-sink temperature from the heat-sink array. We found the fin length that maximizes the heattransfer performance. As the emissivity increased, the effect of geometric parameters on the radiation heat transfer decreased.
Basic Analysis of Heat and Mass Transfer Characteristics of Tubular Membrane Humidifier for Proton Exchange Membrane Fuel Cell
Bae, Ho-June ; Ahn, Kook-Young ; Lee, Young-Duk ; Kang, Sang-Kyu ; Yu, Sang-Seok ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 473~480
DOI : 10.3795/KSME-B.2011.35.5.473
The proton exchange membrane (PEM) fuel cell system is critically dependent on the humidity, which should be properly maintained over the entire operating range. A membrane humidifier is used for the water management in the PEMFC because of the membrane humidifier's reliable performance and zero parasitic power loss. In the PEMFC system, the membrane humidifier is required to provide appropriate humidity for the design point of the fuel cell. Although the performance of the fuel cell depends on the performance of the humidifier, few studies have provided a systematic analysis of the humidifier. We carry out an experimental analysis of the membrane humidifier using a vapor condensation bottle. The dry air pressure, water flow temperature, and air flow rate were chosen as the operating parameters. The results show that the time constant for the dynamic response of the membrane humidifier is relatively short, but additional analysis should be carried out.
A Numerical Analysis of the Behavior of Liquid Film Around a Rotating Cylinder
Lee, Sang-Hyuk ; Lee, Jung-Hee ; Hur, Nahm-Keon ; Seo, Young-Jin ; Kim, In-Cheol ; Lee, Sung-Jin ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 481~486
DOI : 10.3795/KSME-B.2011.35.5.481
It is important to predict the behavior of a liquid film around a rotating cylinder in the film coating process of the steel industry. When the cylinder rotates, the behavior of the liquid film on the rotating cylinder surface is influenced by the cylinder diameter, the rotation speed, the gravitational force, and the fluid properties. These parameters determine the liquid film thickness and the rise of the film on the cylinder surface. In the present study, the two-phase interfacial flow of the liquid film on the rotating cylinder were numerically investigated by using a VOF method. For various rotation speeds, cylinder diameters and fluid viscosities, the behavior of liquid film on the rotating cylinder were predicted. Thicker film around the rotating cylinder was observed with an increase in the rotation speed, cylinder diameter, and fluid viscosity. The present results for the film thickness agreed well with available experimental and analytical results.
Experimental Study of Freeze and Thaw Effect on Gas Diffusion Layer Using XRay Tomography
Je, Jun-Ho ; Kim, Jong-Rok ; Doh, Sung-Woo ; Kim, Moo-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 487~490
DOI : 10.3795/KSME-B.2011.35.5.487
We used X-ray tomography to carry out an experimental study to visualize the effect of freeze and thaw cycles on the gas diffusion layer (GDL) in a polymer electrolyte membrane fuel cell (PEMFC). A PEMFC has freeze and thaw cycles if the fuel cell is operating at a below-freezing ambient temperature. The cycle permanently deforms the fuel-cell capillary structures and reduces the ability of the cell to generate electric power and also reduces its service life. The GDL is the thickest capillary layer in the fuel cell, so it experiences the most deformation. The X-ray tomography facility at the Pohang Accelerator Laboratory was used to observe the structural changes in GDLs induced by a freeze and thaw cycle. We discuss the effects of these structural changes on the power production and service life of PEMFCs.
Numerical Study of Distribution Characteristics of Pulverized Coal According to Operation Condition in PM Burners
Yoon, Sung-Hwan ; Park, Jeong ; Kwon, Oh-Boong ; Park, Ho-Young ; Seo, Sang-Il ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 491~501
DOI : 10.3795/KSME-B.2011.35.5.491
We performed numerical simulation using a DPM (discrete phase model) to identify the optimal operation ranges in two representative PM burners widely used in domestic 500-MW pulverized coal-fired power plants. Recently there has been an increased utilization of low-cost coals such as sub-bituminous coal. We investigate the effects of coal blends on the distribution ratio of coal to air by varying the mass flow rates of pulverized coal and primary air and the particle size. We present and discuss optimal conditions for the distribution ratio of coal to air in PM burners.
Effect of Water Temperature on Heat Transfer Characteristic of Spray Cooling on Hot Steel Plate
Lee, Jung-Ho ; Yu, Cheong-Hwan ; Park, Sang-Jin ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 503~511
DOI : 10.3795/KSME-B.2011.35.5.503
Water spray cooling is a significant technology for cooling of materials from high-temperature up to
. The effects of cooling water temperature on spray cooling are mainly provided for hot steel plate cooling applications in this study. The heat flux measurements are introduced by a novel experimental technique that has a function of heat flux gauge in which test block assemblies are used to measure the heat flux distribution on the surface. The spray is produced by a fullcone nozzle and experiments are performed at fixed water impact density of G and fixed nozzle-totarget spacing. The results show that effects of water temperature on forced boiling heat transfer characteristics are presented for five different water temperatures between 5 to
. The local heat flux curves and heat transfer coefficients are also provided to a benchmark data for the actual spray cooling of hot steel plate cooling applications.
Modal Analysis of Wind Turbine Blade Using Optical-Fiber Bragg-Grating Sensors
Kim, Chang-Hwan ; Paek, In-Su ; Yoo, Neung-Soo ; Nam, Yoon-Su ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 513~516
DOI : 10.3795/KSME-B.2011.35.5.513
The dynamic behavior of a small wind-turbine blade was analyzed experimentally. Arrays of fiber Bragg-Grating (FBG) sensors attached along the blade were used to measure the strains of the blade surface. An impact test was performed to estimate the resonance frequencies of the fundamental and higher modes of the cantilever blade system developed for this study. The results were similar to the results for conventional strain gages. However, FBG sensors could sense modes that strain gauges could not sense. The strains obtained from the FBG sensor array were used to estimate displacement-mode shapes of the blade.
Experimental Study on Energy Separation Characteristics of Vortex Tube
Lee, Jun-Sun ; Han, Keun-Hee ; Park, Sung-Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 517~524
DOI : 10.3795/KSME-B.2011.35.5.517
A vortex tube is a device that can separate small particles from a compressed gas or separate a compressed gas into hot and cold flows. We experimentally analyzed the energy-separation characteristics of a vortex tube with a diameter of 10 mm. We measured the energy-separation characteristics of the vortex tube for different inlet air pressures, orifice diameters, and tube lengths. The orifice diameter and inlet pressure are important for the vortex tube design and operation. The tube length has a small effect on the energy-separation performance. Maximum energy separation occurs for a vortex tube with Dc = 0.7 D and L = 16 D.
Comparison of Combustion Characteristics On the Basis of the Dilution Ratio in Diesel Engines with LPL EGR
Lim, Gi-Hun ; Park, Jun-Hyuk ; Choi, Young ; Lee, Sun-Youp ; Kim, Yong-Min ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 525~531
DOI : 10.3795/KSME-B.2011.35.5.525
Exhaust gas recirculation (EGR) is more effective than selective catalytic reduction (SCR) or lean
trap (LNT) for the reduction of
emissions in diesel engines. A large amount of EGR gas is necessary to satisfy the stringent regulations on
emissions. Low pressure loop (LPL) EGR is almost independent of the variable geometry turbocharger (VGT) at a specific boost pressure, so LPL EGR is better than conventional high pressure loop (HPL) EGR in terms of EGR supply. We compare the influence of HPL EGR and LPL EGR on the combustion characteristics at a constant boost pressure in a diesel engine. The dilution ratio was employed as an independent parameter to analyze the effect of the dilution of the intake charge for each EGR loop. At the same level of
emissions, the fuel consumption and smoke opacity were slightly lower for LPL EGR than for HPL EGR.
Status of Research on Selective Laser Sintering of Nanomaterials for Flexible Electronics Fabrication
Ko, Seung-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 533~538
DOI : 10.3795/KSME-B.2011.35.5.533
A plastic-compatible low-temperature metal deposition and patterning process is essential for the fabrication of flexible electronics because they are usually built on a heat-sensitive flexible substrate, for example plastic, fabric, paper, or metal foil. There is considerable interest in solution-processible metal nanoparticle ink deposition and patterning by selective laser sintering. It provides flexible electronics fabrication without the use of conventional photolithography or vacuum deposition techniques. We summarize our recent progress on the selective laser sintering of metals and metal oxide nanoparticles on a polymer substrate to realize flexible electronics such as flexible displays and flexible solar cells. Future research directions are also discussed.
Characteristic Evaluation of Industrial Radiant Tube Burner System with Oscillating Combustion Technology - NO
Reduction and Performance Improvement -
Oh, Hyuk-Jin ; Cho, Han-Chang ; Cho, Kil-Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 539~545
DOI : 10.3795/KSME-B.2011.35.5.539
Combustion characteristics of industrial radiant tube (RT) burners with forced oscillating combustion technology are investigated using a real-scale (125,000 kcal/h) industrial RT burner facility in both laboratory and field tests. Three different types of industrial RT burners using a by-product gas from the iron-and-steelmaking process are examined in a laboratory facility equipped with a W-type RT. During the field tests, an industrial RT burner is characterized in a large facility equipped with multiple RTs. Their performance and emission controls are investigated under diverse operating conditions. The feasibility of the forced oscillating combustion technology is evaluated by the extent of
reduction and the efficiency improvement. These improvements are able to save energy, extend the RT lifetime, and enhance productivity. The operating conditions that achieve the best performance and emission control for each RT burner are determined.
Painless Microjet Injector Using Laser Pulse Energy
Yoh, Jai-Ick ; Han, Tae-Hee ; Hah, Jung-Moo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 5, 2011, Pages 547~550
DOI : 10.3795/KSME-B.2011.35.5.547
We have developed a laser-based needle-free liquid drug-injection device. A laser beam is focused inside the liquid contained in the rubber chamber of a micro-scale. The focused laser beam causes explosive bubble growth, and the sudden volume increase in a sealed chamber drives a microjet of liquid drug through the micronozzle. The exit diameter of a nozzle is less than 100
, and we verify that the injected microjet is fast enough to penetrate soft human tissue. In the experiment, the microjet penetrated a 5% gelatin-water solution that replicates the human thrombus and pork-fat tissue.