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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 39, Issue 12 - Dec 2015
Volume 39, Issue 11 - Nov 2015
Volume 39, Issue 10 - Oct 2015
Volume 39, Issue 9 - Sep 2015
Volume 39, Issue 8 - Aug 2015
Volume 39, Issue 7 - Jul 2015
Volume 39, Issue 6 - Jun 2015
Volume 39, Issue 5 - May 2015
Volume 39, Issue 4 - Apr 2015
Volume 39, Issue 3 - Mar 2015
Volume 39, Issue 2 - Feb 2015
Volume 39, Issue 1 - Jan 2015
Selecting the target year
Study on Design Optimization of Centrifugal Compressors Considering Efficiency and Weight
Lee, Younghwan ; Ha, Kyung Gu ; Kang, Shin-Hyoung ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 293~299
DOI : 10.3795/KSME-B.2015.39.4.293
Various centrifugal compressors are currently used extensively in industrial fields, where the design requirements are more complicated. This makes it more difficult to determine the optimal design point of a centrifugal compressor. Traditionally, the efficiency is an important factor for optimization. In this study, the weight of the compressor was also considered. The aim of this study was to present the design tendency considering the stage efficiency and weight. In addition, this study suggested possibility of a selection of compressor design objectives at an early design stage based on the optimization results. Only a vaneless diffuser was considered in this case. The Kriging method was used with sample points from 1D design program data. The optimal points were determined in a substitute design space.
Manufacturing of Three-dimensional Micro Structure Using Proton Beam
Lee, Seonggyu ; Kwon, Won Tae ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 301~307
DOI : 10.3795/KSME-B.2015.39.4.301
The diameter of a proton beam emanating from the MC-50 cyclotron is about 2-3 mm with Gaussian distribution. This widely irradiated proton beam is not suitable for semiconductor etching, precise positioning, and micromachining, which require a small spot. In this study, a beam cutting method using a microhole is proposed as an economical alternative. We produced a microhole with aspect ratio, average diameter, and thickness of 428,
, and 9 mm, respectively, for cutting the proton beam. By using this high-aspect-ratio microhole, we conducted machinability tests on microstructures with sizes of tens of
. Additionally, the results of simulation using GEANT4 and those of the actual experiment were compared and analyzed. The outcome confirmed the possibility of implementing a micro process technology for the fabrication of three-dimensional microstructures of 20 micron units using the MC-50 cyclotron with the microhole.
Analytical and Experimental Study on a Thermal Liquid Mass Flow Meter
Kim, Taig Young ; Kang, Chang Hoon ; Shin, Yoon Sub ; Kim, Tae Su ; Choi, Seon Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 309~316
DOI : 10.3795/KSME-B.2015.39.4.309
Numerical analysis and experimental verification of a thermal liquid mass flow meter (LMFM) were performed. The configuration of the LMFM was the same as a gas mass flow meter (GMFM), but the opposite results in temperature difference between upstream and downstream thermistors occurred. In the case of the gas, the convection depending on the flow of thermal mass was small and comparable to the conduction through the sensor tube wall. The temperature difference was proportional to the mass flow rate due to their interaction. For the liquid flow, the convection overwhelmed the wall conduction because of the large flow of thermal mass caused by high density. The temperature difference in this case was inversely proportional to the mass flow rate. The tube diameter and heater wiring width are important design parameters, and the optimized sensor can be used to measure and control the infinitesimal liquid flow rate.
Feasibility of a Solar Thermal Organic Rankine Cycle Power Plant for an Apartment Complex with Aspen Plus
Im, Seokyeon ; Kim, Hyung-Geun ; Yu, Sangseok ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 317~324
DOI : 10.3795/KSME-B.2015.39.4.317
In this study, a solar thermal system is designed to provide hot water and electricity for improvement of solar thermal energy availability in an apartment complex. The electricity is generated with Organic Rankine Cycle (ORC) by the solar thermal energy. R134a, R141b and R245fa are selected for operating fluid of the solar thermal ORC system. ORC with R245fa shows the best performance based on the variation of pressure. The irreversibility of component showed that the technology advance of the evaporator ensures a performance improvement. The sensitivity study results indicate that the turbine performance is most effective way to improve the performance of ORC system. An economic analysis showed that approximately 50% more income could be achieved by a solar thermal ORC system with a hot water supply.
Flow instability in Flow Past O-grooved Circular Cylinder
Kim, Jaehee ; Yang, Kyung-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 325~333
DOI : 10.3795/KSME-B.2015.39.4.325
This study was devoted to elucidating the change in the flow characteristics of a laminar flow past a circular cylinder by modifying the cylinder shape with O-grooves. A numerical analysis was performed in a two-dimensional framework. The cylinder was represented using an immersed boundary method and marker particles on a Cartesian grid system. The number and locations of the O-grooves were the key parameters. An analysis of the flow pattern and flow-induced forces was performed at Re = 40 and 50. In addition, we calculated the critical Reynolds number depending on the number of O-grooves and their locations.
Stokes Flow Through a Microchannel with Projections of Constant Spacing
Son, JeongSu ; Jeong, Jae-Tack ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 335~341
DOI : 10.3795/KSME-B.2015.39.4.335
In this study, we analyzed a two-dimensional Stokes flow through a microchannel containing projections with constant spacing attached to each wall. The projections on the top and bottom walls were semi-circular in shape, with in-phase locations. By considering the periodicity and symmetry of the flow, the eigenfunction expansion and least squared error method were applied to determine the stream function and pressure distribution. For some typical radius and spacing values, the streamline patterns and pressure distributions in the flow field are shown, and the shear stress distributions on the boundary walls are plotted. In addition, the average pressure gradients in the microchannel are also calculated and shown with the radius and spacing of the projections. In particular, the results for the case of extremely small gaps between the projections on the top and bottom walls are in good agreement with the lubrication results.
Experimental Study on Effect of Inclination Angle on Natural Convection from Cylindrical Heatsinks with Plate Fins
Park, Kuen Tae ; Kim, Hyun Jung ; Yoo, Jaisuk ; Lee, Moon Gu ; Kim, Dong-Kwon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 343~350
DOI : 10.3795/KSME-B.2015.39.4.343
The natural convection heatsink is the most commonly used cooling device, especially for high-power LED lights, because of its reliability and low long-term cost. High power LED lights are generally used in an inclined configuration for street lamps and security lamps. However, it was difficult to estimate the thermal performance of an inclined heatsink, because the results from previous studies are not applicable to the inclined configuration. In this study, we measured the thermal performance of an inclined cylindrical heatsink with plate fins. Various fin numbers, fin heights, base temperatures, and inclination angles (
) were examined. Based on the experimental results, the Nusselt number correlation is presented. This correlation is applicable when the Rayleigh number, ratio of the fin height to cylinder diameter, and fin number are in the ranges 100,000-600,000, 1/6-1/2, and 9-72, respectively.
PM Reduction Characteristics of Gasoline Direct Injection Engines with Different Types of GPFs
Yi, Ui Hyung ; Park, Cheolwoong ; Lee, Sunyoup ; Lim, Jong Han ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 351~358
DOI : 10.3795/KSME-B.2015.39.4.351
In the recent times, the use of gasoline direct injection (GDI) engines has been regarded as a means of enhancing conformance to emission regulations and improving fuel efficiency. GDI engines have been widely adopted in the recent years for their better engine performance and fuel economy compared to those of conventional MPI gasoline engines. However, they present some disadvantages related to the mass and quantity of particulate matter generated during their use. This study investigated the nanoparticle characteristics of the particulate matter exhausted from a GDI engine vehicle installed with different types of gasoline particulate filters, after subjecting it to ultra-lean burn driving conditions. Three metal foam and metal fiber filters were used for each experimental condition. The number concentrations of particles were analyzed for understanding their behavior, and the reduction characteristics were obtained for each type of filter.
Behavior of Liquid Droplet Driven by Capillarity Force Imbalance on Horizontal Surface Under Various Conditions
Myong, Hyon Kook ; Kwon, Young Hoo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 359~370
DOI : 10.3795/KSME-B.2015.39.4.359
The present study aims to numerically investigate the behavior of liquid droplet driven by capillarity force imbalance on horizontal surfaces ranging from hydrophilic to hydrophobic, under various conditions. The droplet behavior has been simulated using an in-house solution code(PowerCFD), which employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with interface capturing method(CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing. The detailed droplet behavior was obtained under various conditions for droplets with different initial shapes, contact angles and surface tension forces(or Bond number). The mechanism of droplet transport was examined using the numerical results on the droplet shapes.
Measurement of Micro Gas Turbine Power Pack Performance for Electric Vehicle Range Extenders Under Various Electrical Loads and Gear Ratios
Sim, Kyuho ; Park, Jisu ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 371~378
DOI : 10.3795/KSME-B.2015.39.4.371
Range extenders, which are power generation systems driven by small engines, extend the driving distance and time of electric vehicles (EVs) through continuous charging of batteries. The currently used range extenders with gasoline engines pose limitations with regard to the realization of high-power compact systems, owing to their complex structure and low energy density. In contrast, micro gas turbine (MGT) range extenders (MGT power packs) possess high power and low weight, and can therefore be significantly reduced in size despite increase in speed. In this study, an MGT power pack for the range extenders of EVs was developed using a turbo-prop micro turbine, an alternator for passenger vehicles and electric batteries. The operating characteristics of the MGT power pack were measured through a series of experiments conducted under electrical no-load and load conditions. Their power generation performance and efficiency were measured under various electrical loads and power transmission gear ratios. From the results, electrical load was found to have no influence on power generation performance. The maximum electrical power output was 0.8 kW at a core turbine speed of 150 krpm, and the application of 3:1 reduction gear to the turbine output shaft increased the power to 1.5 kW by 88%. This implies that the test results demonstrated stable power generation performance of the MGT power pack regardless of vehicle load changes, thus revealing its feasibility for use with the range extenders of EVs.
High Speed and Continuous Electrospinning Printing Using Polymer Ink
Zhang, Da-Hai ; Kwon, Kye-Si ;
Transactions of the Korean Society of Mechanical Engineers B, volume 39, issue 4, 2015, Pages 379~384
DOI : 10.3795/KSME-B.2015.39.4.379
Electrospinning has recently been used for micropatterning. The electrospinning method as a patterning tool has the advantage of a rapid patterning speed because it is based on a continuous printing mode rather than a drop-on-demand mode. To obtain stable continuous printing, a high molecular weight polymer must be mixed with functional materials for patterning. In this paper, polyethylene oxide (PEO) was used. The effect of polymer on viscosity and formation of a Taylor cone jet from the electrospinning nozzle was investigated. Finally, the electrospinning patterning results of a silver paste ink on a glass substrate were investigated.