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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 28, Issue 12 - Dec 2004
Volume 28, Issue 11 - Nov 2004
Volume 28, Issue 10 - Oct 2004
Volume 28, Issue 9 - Sep 2004
Volume 28, Issue 8 - Aug 2004
Volume 28, Issue 7 - Jul 2004
Volume 28, Issue 6 - Jun 2004
Volume 28, Issue 5 - May 2004
Volume 28, Issue 4 - Apr 2004
Volume 28, Issue 3 - Mar 2004
Volume 28, Issue 2 - Feb 2004
Volume 28, Issue 1 - Jan 2004
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Effects of Particle Shapes on Unipolar Diffusion Charging of Non-Spherical Particles
Oh, Hyun-Cheol ; Park, Hyung-Ho ; Kim, Sang-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 501~509
DOI : 10.3795/KSME-B.2004.28.5.501
Unipolar diffusion charging of non-spherical particles was investigated for various particle shapes. We researched with TiO
agglomerates produced by the thermal decomposition of titanium tetraisopropoxide (TTIP) vapor. TTIP was converted into TiO
, in the furnace reactor and was subsequently introduced into the sintering furnace. Increasing the temperature in the sintering furnace, aggregates were restructured into higher fractal dimensions. The aggregates were classified according to their mobility using a differential mobility analyzer. The projection area and the mass fractal dimension of particles were measured with an image processing technique performed by using transmission electron microscope (TEM) photograph. The selected aggregates were charged by the indirect photoelectric-charger and the average number of charges per particle was measured by an aerosol electrometer and a condensation particle counter. For the particles of same mobility diameter, our results showed that the particle charge quantity decreases as the sintering temperature increases. This result is understandable because particles with lower fractal dimension have larger capacitance and geometric surface area.
Development of a New Sensor with Divided Multiple Long and Short Wires in Transient Hot-wire Technique
Lee, Shin-Pyo ; Lee, Myung-Hoon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 510~517
DOI : 10.3795/KSME-B.2004.28.5.510
A fine hot-wire is used both as a heating element and a temperature sensor in transient hot-wire method. The traditional sensor system is unnecessarily big so that it takes large fluid volume to measure the thermal conductivity. To dramatically reduce this fluid volume, a new sensor fabrication and a data processing method are proposed in this article. Contrast to the conventional and most popular two wire sensor, the new sensor system is made up of divided multiple long and short wires. Through validation experiments, it is found that the measured thermal conductivities of the glycerin are exactly same each other between the conventional and proposed new method. Also some technical considerations in arranging the multiple wires are briefly discussed.
Hot and Cool Temperature Control of the Car-Seat Utilizing the Thermoelectric Device
Choi, Hyeung-Sik ; Kim, You-Shin ; Jeon, hang-Hoon ; Yun, Sang-Kook ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 518~525
DOI : 10.3795/KSME-B.2004.28.5.518
The thermoelectric device was applied to a car seat to control the hot temperature in the summer and cold temperature in the winter. The characteristics of the device used to a car seat were analyzed. The air conditioning structure was designed to regulate the hot side of the thermoelectric device. To control the temperature of the car seat, a robust control algorithm based on the sliding mode control was applied, and a controller using one-chip microprocessor was developed. The performance of the proposed controller through experiments was shown.
Near-Wall Modelling of Turbulent Heat Fluxes by Elliptic Equation
Shin, Jong-Keun ; An, Jeong-Soo ; Choi, Young-Don ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 526~534
DOI : 10.3795/KSME-B.2004.28.5.526
A new second-moment closure model for turbulent heat fluxes is proposed on the basis of the elliptic equation. The new model satisfies the near-wall balance between viscous diffusion, viscous dissipation and temperature-pressure gradient correlation, and also has the characteristics of approaching its respective conventional high Reynolds number model far away from the wall. The predictions of turbulent heat transfer in a channel flow have been carried out with constant wall heat flux and constant wall temperature difference boundary conditions respectively. The velocity field variables are supplied from the DNS data and the differential equations only fur the mean temperature and the scalar flux are solved by the present calculations. The present model is tested by direct comparisons with the DNS to validate the performance of the model predictions. The prediction results show that the behavior of the turbulent heat fluxes in the whole region is well captured by the present model.
Heat(Mass) Transfer Characteristics in the Tip-Leakage Flow Region of a High-Turning Turbine Rotor Blade
Lee, Sang-Woo ; Kwon, Hyun-Goo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 535~544
DOI : 10.3795/KSME-B.2004.28.5.535
The heat (mass) transfer characteristics in the tip-leakage flow region of a high-turning first-stage turbine rotor blade has been investigated by employing the naphthalene sublimation technique. The heat transfer data in the tip-leakage flow area for the tip clearance-to-span ratio, h/s, of 2.0% are compared with those in endwall three-dimensional flow region without tip clearance (h/s : 0.0 %). The result shows that the thermal load in the tip-leakage flow region for h/s
Numerical Analysis of Spray Behavior and Vaporization Characteristic of GDI Engine Injector Under Ambient Conditions
Shim, Young-Sam ; Hwang, Soon-Chul ; Kim, Duck-Jool ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 545~552
DOI : 10.3795/KSME-B.2004.28.5.545
The purpose of this study is to improve the prediction ability of the atomization and vaporization processes of GDI spray. Several models have been introduced and compared. The atomization process was modeled using hybrid breakup model that is composed of Linearized Instability Sheet Atomization (LISA) model and Aerodynamically Progressed TAB (APTAB) model. The vaporization process was modeled using Spalding model and Abramzon ＆ Sirignano model. Exciplex fluorescence method was used for comparing calculated with experimental results. The experiment and computation were performed at the ambient pressure of 0.1 MPa, 0.5 MPa and 1.0 MPa and the ambient temperature of 293k and 473k. Comparison of calculated and experimental spray characteristics was carried out and the calculated results of GDI spray showed good agreement with experimental results.
Numerical Study for Effects of Density-Stratification on Wake Behind a Sphere
Lee, Sung-Su ; Yang, Kyung-Soo ; Park, Chan-Wook ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 553~559
DOI : 10.3795/KSME-B.2004.28.5.553
Stratified flow past a three-dimensional obstacle such as a sphere has been a long-lasting subject of geophysical, environmental and engineering fluid dynamics. In order to investigate the effect of the stratification on the near wake, in particular, the unsteady vortex formation behind a sphere, numerical simulations of stratified flows past a sphere are conducted. The time-dependent Navier-Stokes equations are solved using a three-dimensional finite element method and a modified explicit time integration scheme. Laminar flow regime is considered, and linear stratification of density is assumed under Bossiness approximation. The computed results include the characteristics of the near wake and the unsteady vortex shedding. With a strong stratification, the separation on the sphere is suppressed and the wake structure behind the sphere becomes planar, resembling that behind a vertical cylinder.
A Study on the 3-D Airflow and Dynamic Cross Contamination in the Photolithography Process Cleanroom
Noh, Kwang-Chul ; Oh, Myung-Do ; Lee, Seung-Chul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 560~568
DOI : 10.3795/KSME-B.2004.28.5.560
We performed the numerical study on the characteristics of the 3-D airflow and dynamic cross contamination in the photolithography process cleanroom. The nonunifurmity, the deflection angle and the global cross contamination were used for analyzing the characteristics and performances of cleanroom. From the numerical results, we knew that the airflow characteristics of the cleanrooms are largely affected by the porosity of panel and the adjustment of dampers and the global cross contamination varies with the location of source and the passage of time through the concentration ratio.
An Experimental Study on the Lift-off Behavior of Tone-Excited Propane Non-premixed Jet Flames
Kim, Seung-Gon ; Kim, Kang-Tae ; Park, Jeong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 569~579
DOI : 10.3795/KSME-B.2004.28.5.569
The lift-off characteristics of lifted laminar propane jet flames highly diluted with nitrogen are investigated introducing acoustic forcing with a fuel tube resonance frequency. A flame stability curve is obtained according to forcing strength and the nozzle exit velocity for N2 diluted flames. Flame lift-off behavior is globally classified into three regimes; 1) a weakly varying partially premixed behavior caused by a collapsible mixing for large forcing strength, 2) a coexistent behavior of the edge flame and a weakly varying partially premixed behavior for moderate forcing strength, and 3) edge flame or triple flame behavior for small forcing. It is shown that the laminar lifted flame with forcing affects flame lift-off behavior considerably, and is also clarified that the flame characteristic of flame base is well described with the penetration depth of the degree of mixing,
/. It is also confirmed that the weakly varying partially premixed flame caused by a collapsible mixing fur large forcing strength behaves as that just near flame blow-out in turbulent lift-off flame.
Radiative Heat Transfer in Discretely Heated Irregular Geometry with an Absorbing, Emitting, and An-isotropically Scattering Medium Using Combined Monte-Carlo and Finite Volume Method
Byun, Do-Young ; Lee, Chang-Jin ; Chang, Seon-Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 580~586
DOI : 10.3795/KSME-B.2004.28.5.580
The ray effects of finite volume method (FVM) or discrete ordinate method (DOM) are known to show a non-physical oscillation in solution of radiative heat transfer on a boundary. This wiggling behavior is caused by the finite discretization of the continuous control angle. This article proposes a combined procedure of the Monte-Carlo and finite-volume method (CMCFVM) for solving radiative heat transfer in absorbing, emitting, and an-isotropically scattering medium with an isolated boundary heat source. To tackle the problem, which is especially pronounced in a medium with an isolated heat source, the CMCFVM is suggested here and successfully applied to a two-dimensional circular geometry.
Measurements of Plasma Flows in Micro-Tube/Channel Using Micro-PIV
Ko, Choon-Sik ; Yoon, Sang-Youl ; Ki, Ho-Seong ; Kim, Kyung-Chun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 587~593
DOI : 10.3795/KSME-B.2004.28.5.587
In this paper, flow characteristics of plasma flow in a micro-tube were investigated experimentally using micro particle image velocimetry(micro-PIV). For comparison, the experiments were repeated for deionized(DI) wale. instead of plasma. Both velocity profiles of plasma and do-ionized water are well agreed with the theoretical velocity distribution of newtonian fluid. We also carried out generating plasma-in-oil droplet formation at a Y-junction microchannel. In order to clarify the hydrodynamic aspects involved in plasma droplet formation, Rhodamine-B were mixed with plasma only for visualization of plasma droplet. With oil as the continuous phase and plasma as the dispersed phase, plasma droplet can be generated in a continuous phase flow at a Y-junction. For given experimental parameters, regular-sized droplets are reproducibly formed at a uniform flow conditions.
An Experimental Study on the Performance Characteristics with Height of a Fin-Tube Liquid Desiccant Dehumidifier
Lee, Su-Dong ; Park, Moon-Soo ; Chung, Jin-Eun ; Choi, Young-Seok ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 594~603
DOI : 10.3795/KSME-B.2004.28.5.594
Several desiccant cooling systems have been developed in terms of cost and performance. In this study a fin-tube exchanger has been used for liquid desiccant dehumidification system. This dehumidifier has been designed to study the absorption characteristic of the aqueous triethylene glycol(TEG) solution which has the flow range from 20 to 50 LPM. The dehumidifier performance characteristics of working factor variables such as inlet solution flow rate, air flow rate, solution concentration and brine temperature have been analyzed. This dehumidifier has the ability to provide running while saving the latent heat load of total energy. The result of this experiment can provide useful data for hybrid air conditioning system.
A Basic Study of Thermal-Fluid Flow Analysis Using Grid Computing
Hong, Seung-Do ; Ha, Yeong-Man ; Cho, Kum-Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 604~611
DOI : 10.3795/KSME-B.2004.28.5.604
Simulation of three-dimensional turbulent flow with LES and DNS lakes much time and expense with currently available computing resources and requires big computing resources especially for high Reynolds number. The emerging alternative to provide the required computing power and working environment is the Grid computing technology. We developed the CFD code which carries out the parallel computing under the Grid environment. We constructed the Grid environment by connecting different PC-cluster systems located at two different institutes of Pusan National University in Busan and KISTI in Daejeon. The specification of PC-cluster located at two different institutes is not uniform. We run our parallelized computer code under the Grid environment and compared its performance with that obtained using the homogeneous computing environment. When we run our code under the Grid environment, the communication time between different computer nodes takes much larger time than the real computation time. Thus the Grid computing requires the highly fast network speed.
Stereoscopic PIV Measurement on Turbulent Flows in a Waterjet Intake Duct
Kwon, Seong-Hun ; Yoon, Sang-Youl ; Chun, Ho-Hwan ; Kim, Kyung-Chun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 28, issue 5, 2004, Pages 612~618
DOI : 10.3795/KSME-B.2004.28.5.612
Stereoscopic PIV measurements were made in the wind tunnel with the actual size waterjet model. The main wind tunnel provides the vehicle velocity while the secondary wind tunnel adjusts the jet issuing velocity. Experiments were performed at the range of jet to vehicle velocity ratio (JVR), 3.75 to 8.0 and the Reynolds number of 220,000 based on the jet velocity and the hydraulic diameter of the waterjet intake duct. Wall pressure distributions were measured for various JVRs. Three dimensional velocity fields were obtained at the inlet and outlet of the intake duct. It is found that severe acceleration is occurred at the lip region while deceleration is noticeable at the ramp side. The detailed three dimensional velocity fields can be used as the accurate velocity input for the CFD simulation. It is interesting to note that there are many different types of vortices in the instantaneous velocity field. It can be considered that those vortices are generated by the corner of rectangular section of the intake and Gortler vortices due to the curved wall. However, typical secondary flow with a pair of counter rotating vortex pair is clearly seen in the ensemble averaged velocity field.