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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 37, Issue 12 - Dec 2013
Volume 37, Issue 11 - Nov 2013
Volume 37, Issue 10 - Oct 2013
Volume 37, Issue 9 - Sep 2013
Volume 37, Issue 8 - Aug 2013
Volume 37, Issue 7 - Jul 2013
Volume 37, Issue 6 - Jun 2013
Volume 37, Issue 5 - May 2013
Volume 37, Issue 4 - Apr 2013
Volume 37, Issue 3 - Mar 2013
Volume 37, Issue 2 - Feb 2013
Volume 37, Issue 1 - Jan 2013
Selecting the target year
Performance Analysis of Hybrid Desiccant Chiller Based on Field Test
Ahn, Joon ; Yun, Changho ; Kang, Byung Ha ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 621~627
DOI : 10.3795/KSME-B.2013.37.7.621
Field tests of hybrid desiccant cooling systems were conducted from July to August 2011. Data were monitored and transferred in real time over the Internet. The monitored variableswere analyzed to determine the performance characteristics under outdoor conditions. A series of system simulations has been conducted for outdoor conditions of the field tests. The results agree well with the experimental data in general. The system performance has been shown to deteriorate for wetter conditions, as predicted by the simulation.
Theoretical and Computational Analyses of Bernoulli Levitation Flows
Nam, Jong Soon ; Kim, Gyu Wan ; Kim, Jin Hyeon ; Kim, Heuy Dong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 629~636
DOI : 10.3795/KSME-B.2013.37.7.629
Pneumatic levitation is based upon Bernoulli's principle. However, this method is known to require a large gas flow rate that can lead to an increase in the cost of products. In this case, the gas flow rate should be increased, and the compressible effects of the gas may be of practical importance. In the present study, a computational fluid dynamics method has been used to obtain insights into Bernoulli levitation flows. Three-dimensional compressible Navier-Stokes equations in combination with the SST k-
turbulence model were solved using a fully implicit finite volume scheme. The gas flow rate, workpiece diameter,and clearance gap between the workpiece and the circular cylinder were varied to investigate the flow characteristics inside. It is known that there is an optimal clearance gap for the lifting force and that increasing the supply gas flow rate results in a larger lifting force.
Study of Natural Convection of Magnetic Fluid in Cubic Cavity
Seo, Jae-Hyeong ; Lee, Moo-Yeon ; Seo, Lee-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 637~646
DOI : 10.3795/KSME-B.2013.37.7.637
This study aims to numerically investigate the natural convection characteristics of a magnetic fluid in a cubic cavity. The governing equations of the magnetic fluid are solved using the Generalized-Simplified Marker and Cell Method (GSMAC). The natural convection and heat transfer characteristics of the magnetic fluid were analyzed by varying the intensity and direction of the magnetic field. As a result, it was found that the natural convection characteristics were controlled by the intensity and direction of the magnetic field, and the mean Nusselt numbers were minimized at a vertical intensity of H=-4000 and horizontal intensity of H=12000 of the magnetic field. In addition, the mean Nusselt numbers increased with the intensities of the magnetic field, regardless of the direction of the magnetic field.
Experimental Study of Evaporation of Nanofluid Droplet
Kim, Yeung Chan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 647~653
DOI : 10.3795/KSME-B.2013.37.7.647
The evaporation characteristics of nanofluid droplets on a heated solid surface were experimentally investigated. The experiments were conducted using pure water and a nanofluid of water mixed with CuO nanoparticles, and the solid surface was made of a copper block heated by a nine cartridge heater. The experimental results showed that the evaporation rate of the nanofluid droplet was higher than that of the pure water droplet on the heated solid surface because nanoparticles increased the thermal conductivity of the nanofluid. Furthermore, it was found that the evaporation rate of the nanofluid droplet increased with the solid surface roughness. This may be because the actual area of the liquid-solid interface increased with the solid surface roughness.
Effect of Secondary Flow Direction on Film Cooling Effectiveness
Park, Sehjin ; Choi, Seok Min ; Sohn, Ho-Seong ; Chung, Heeyoon ; Cho, Hyung Hee ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 655~663
DOI : 10.3795/KSME-B.2013.37.7.655
Several studies of film cooling were accomplished with a secondary flow channel parallel to the main flow. In real turbine blades, however, the direction of the secondary flow channel is generally normal to the main flow. Thus, this study performs a numerical analysis to investigate the effects of the direction of secondary flow on the effectiveness of double-jet film cooling. The blowing ratio is 1 and 2, and the lateral injection angle is
. The parallel channel case creates a well-developed anti-kidney vortex with a blowing ratio of 1, and the laterally averaged film cooling effectiveness of the parallel channel is enhanced compared to the normal channel. The normal channel shows higher performance with a blowing ratio of 2. Both cases show high film cooling effectiveness. These phenomena can be attributed to a high blowing ratio and flow rate rather than an anti-kidney vortex.
Study of Li-Ion Diffusion and Phase Transition in Cathode of Li-Ion Battery
Kim, Sooil ; Kim, Dongchoul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 665~667
DOI : 10.3795/KSME-B.2013.37.7.665
Metal ions show various transitions in the cathode of a lithium-ion battery. The diffusion process of lithiumions and the phase transition in the cathode need to be thoroughly understood for the advanced design of an improved lithium-ion battery. Here, we employ a phase field model to simulate the diffusion of lithiumions and to study the phase transition in the cathode.
Experimental Study of Machining Process of Polymer Mold for Fabrication of Three-Dimensional Hydrogel Scaffold
Lee, Pil-Ho ; Lee, Sang Won ; Kim, Daehoon ; Kim, Si Hyeon ; Sung, Jong Hwan ; Chung, Haseung ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 669~674
DOI : 10.3795/KSME-B.2013.37.7.669
A three-dimensional hydrogel scaffold has been proposed for the effective production of biomimetic intestinal villi to reduce ethical and cost problems caused by animal testing in pharmaceutical development. This study explores an experimental approach to develop a new technique based on laser machining and microdrilling processes to produce a plastic mold for the fabrication of a three-dimensional hydrogel scaffold. For process optimization, both the laser machining and the microdrilling experiments are conducted by varying the experimental conditions, and structural characterization of the mold and intestinal villi were performed using SEM (scanning electron microscope) and OM (optical microscope) images. Polycarbonate (PC) was used as a candidate material. The experimental results show that intestinal villi can be fabricated by both laser and microdrilling machining processes.
Cumulative Distributions and Flow Structure of Two-Passage Shear Coaxial Injector with Various Gas Injection Ratio
Lee, Inchul ; Kim, Dohun ; Koo, Jaye ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 675~682
DOI : 10.3795/KSME-B.2013.37.7.675
To verify the effect of inner- and outer-stage gas jets, a shear coaxial injector was designed to analyze the axial velocity profile and breakup phenomenon with an increase in the measurement distance. When the measurement position was increased to Z/d=100, the axial flow showed a fully developed shape due to the momentum transfer, aerodynamic drag effect, and viscous mixing. An inner gas injection, which induces a higher momentum flux ratio near the nozzle, produces the greater shear force on atomization than an outer gas injection. Inner- and Outer-stage gas injection do not affect the mixing between the inner and outer gas flow below Z/d=5. The experiment results showed that the main effect of liquid jet breakup was governed by the gas jet of an inner stage. As the nozzle exit of the outer-stage was located far from the liquid column, shear force and turbulence breaking up of the liquid jets do not fully affect the liquid column. In the case of an inner-stage gas injection momentum flux ratio within 0.84, with the increase in the outer gas momentum flux ratio, the SMD decreases. However, at an inner-stage gas jet momentum flux ratio over 1.38, the SMD shows the similar distribution.
Numerical Investigation of Mixing Characteristics in a Cavity Flow by Using Hybrid Lattice Boltzmann Method
Shin, Myung Seob ; Jeon, Seok Yun ; Yoon, Joon Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 683~693
DOI : 10.3795/KSME-B.2013.37.7.683
In this study, the mixing characteristics in lid-driven cavity flows were studied numerically by using a hybrid lattice Boltzmann method (HLBM). First, we compared the numerical results from single-relaxation-time (LB-SRT) and multi-relaxation-time (LB-MRT) models to examine their reliability. In most of the cavity flow, the results from both the LB-SRT and the LB-MRT models were in good agreement with those using a Navier-Stokes solver for Re=100-5000. However, the LB-MRT model was superior to the LB-SRT model for the simulation of higher Reynolds number flows having a geometrical singularity with much lesser spatial oscillations. For this reason, the LB-MRT model was selected to study the mass transport in lid-driven cavity flows, and it was demonstrated that mass transport in the fluid was activated by a recirculation zone in the cavity, which is connected from the top to the bottom surfaces through two boundary layers. Various mixing characteristics such as the concentration profiles, mean Sherwood (Sh) numbers, and velocity were computed. Finally, the detailed transport mechanism and solutions for the concentration profile in the cavity were presented.
Surfactant-Induced Suppression of the Thermocapillary Flow in Evaporating Water Droplets
Yun, Sungchan ; Kim, Tae Kwon ; Lim, Hee Chang ; Kang, Kwan Hyoung ; Lim, Geunbae ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 695~701
DOI : 10.3795/KSME-B.2013.37.7.695
The suppression of a thermocapillary flow (Marangoni flow) by a nonionic surfactant is experimentally investigated for evaporating pure water droplets on hydrophobic substrates. The experiment shows that as the initial concentration of the surfactant increases, the velocity and lifetime of the flow monotonically decrease. The result confirms the no-slip boundary condition at a liquid-air interface, which is explained on the basis of the previous model regarding the effect of surfactants on the no-slip condition. Interestingly, at an initial concentration much less than a critical value, it is found that depinning of the contact line occurs during the early stage of evaporation, which is ascribed to a reduction in the contact angle hysteresis owing to the presence of the Marangoni flow.
Development of Hip Joint Mechanical Stem for Minimally Invasive Surgery
Lee, Sunghyun ; Bae, Ji-Yong ; Jeon, Insu ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 703~708
DOI : 10.3795/KSME-B.2013.37.7.703
Conventional total hip joint replacement(THR) surgery requires a long incision and long rehabilitation time. The stem used in THR is inserted into the cancellous bone of the femur where it plays the role of the artificial joint. Minimally invasive surgery(MIS) has been devised to reduce muscle damage to patients. In this study, a mechanical stem was developed on the basis of MISto reduce the incision length through the principle of the gear. The mechanical stem consists of six components. A prototypical model for a mechanical stem was fabricated using an acryl-based polymer, and its workability was confirmed. To actualize the mechanical stem, a three-dimensional Bio-CAD modeling technique was applied. The hip joint area based on computed tomography(CT) was reconstructed. The safety of the mechanical stem by applying more load than the weight of a man under virtual surgery environment conditions was confirmed by finite element analysis.
CFD Based Shape Design of Guide Vane for Fan Filter Unit
Jang, Jun Hwan ; Ahn, Joon ; Myong, Hyon Kook ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 7, 2013, Pages 709~716
DOI : 10.3795/KSME-B.2013.37.7.709
A fan filter unit (FFU) is a device which supplies clean air from the ceiling in a clean room. With an increase in its size, velocity variation occurs within the exhaust plane and this damage the product quality or productivity. Hence, a guide vane is installed inside the device to enhance the velocity uniformity. Because the vane reduces the flow rate for a given pumping power, an optimum design is required to achieve velocity uniformity while minimizing the flow rate reduction at the same time. To find a geometry that satisfies these requirements, a series of numerical simulations has been conducted while changing the angle and length of the guide vanes. By changing the geometry of the side guide vane, the velocity uniformity increased by 3.7% and the flow rate decreased by 1.5%. For the center guide vane, the velocity uniformity increased by 2.9% and the flow rate decreased by 0.7%.