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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 31, Issue 12 - Dec 2007
Volume 31, Issue 11 - Nov 2007
Volume 31, Issue 10 - Oct 2007
Volume 31, Issue 9 - Sep 2007
Volume 31, Issue 8 - Aug 2007
Volume 31, Issue 7 - Jul 2007
Volume 31, Issue 6 - Jun 2007
Volume 31, Issue 5 - May 2007
Volume 31, Issue 4 - Apr 2007
Volume 31, Issue 3 - Mar 2007
Volume 31, Issue 2 - Feb 2007
Volume 31, Issue 1 - Jan 2007
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The Effect on the Heat Transfer According to Geometric Variation of Air-Fin Vaporizer with at Cryogenic Temperature
Lee, Sang-Chul ; Shin, You-Sik ; Bae, Kang-Youl ; Jeong, Hyo-Min ; Chung, Han-Shik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 581~587
DOI : 10.3795/KSME-B.2007.31.7.581
At present time, LNG demand of the world is increasing and the piping line for NG transportation has been already installed in Korea. The air fm vaporizer is, however, required because of the transportation for remotely local areas. This paper numerically investigates on the heat transfer characteristics of relevant geometric variations of air-fin vaporizer which is heated by air not by sea water. This vaporizer must be designed in consideration of both efficiency and economics because air is relatively a little heat source. In this study, the pipe and the longitudinal fins are fundamental geometric considerations. Main parameters of geometry are the number, the thickness, and the length of the fins. Finally, the results of heat transfer effects are investigated with the characteristics of each parameter variation.
Performance Characteristics of a Polymer Electrolyte Fuel Cell with the Anodic Supply Mode
Lee, Yong-Taek ; Park, Cha-Sik ; Heo, Jae-Hyeok ; Kim, Yong-Chan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 588~595
DOI : 10.3795/KSME-B.2007.31.7.588
The water transport inside a polymer electrolyte fuel cell (PEFC) varied according to the anodic supply mode. The performance characteristics of a PEFC which can be affected by the water transport were observed with the anodic supply mode. In the flow-through and recirculation mode the performance showed no reduction with time because the flow in the anode was not stagnated. In the dead-end mode, without any discharged gas, the water remains inside of the anode, which caused the reduction of the performance with the lapse of time. However, even in the dead-end mode, little reduction of the performance with time was shown when only the anode was humidified externally. It means that the back-diffusion was the major factor to the accumulation of water in the anode rather than external humidification.
A Numerical Study of Heat and Mass Transfer Model of LII for Nanoscale Soot Particles
Kim, Gyu-Bo ; Shim, Jae-Young ; Chang, Young-June ; Jeon, Chung-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 596~603
DOI : 10.3795/KSME-B.2007.31.7.596
As increasing interest for soot emission. etc in combustion systems, various studies are being carried out for the reduction and measurement techniques of soot. Especially, laser induced incandescence is the useful measurement technique which has distinguished spatial and temporal resolution for primary particle size, volume fraction and aggregated particle size etc. Time resolved laser induced incandescence is the technique for measuring primary particle size that is decided to solve the signal decay rate which is related to the cooling behavior of heated particle by pulsed laser. The cooling behavior of heated particle is able to represent the heat and mass transfer model which are involved constants of soot property for surround gas temperature on the our previous work. In this study, it is applied to the time-dependence thermodynamic properties for soot temperature instead of constants of soot property for surround gas temperature and compared two different model results.
Effects of Bottom Inflow Area on Pool Boiling Heat Transfer in a Vertical Annulus
Kang, Myeong-Gie ; Yoo, Joo-Sik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 604~610
DOI : 10.3795/KSME-B.2007.31.7.604
To investigate effects of the inflow area on pool boiling heat transfer in a vertical annulus, the inflow area at its bottom has been changed from 0 to
. For the test, a heated tube of 34 mm diameter and water at atmospheric pressure have been used. To elucidate effects of the inflow area on heat transfer results of the annulus are compared to the data of a single unrestricted tube. The change in the inflow area at the bottom of the annulus results in much variation in heat transfer coefficients. When the inflow area is
the deterioration point of heat transfer coefficients gets moved up to the higher heat fluxes because of the convective flow at the bottom regions.
The Droplet Size Distribution of Fan Spray at Different Surrounding Conditions
Moon, Seok-Su ; Choi, Jae-Joon ; Bae, Choong-Sik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 611~619
DOI : 10.3795/KSME-B.2007.31.7.611
In this study, the droplet size distribution of a slit injector at different surrounding conditions, such as air flow and fuel temperature, were investigated. Phase Doppler anemometry (PDA) was utilized to investigate the initial droplet size distribution and the effect of fuel temperature and air flow on droplet size distribution. The entrained air motion was also evaluated by the temporal velocity profile of droplets. When the air flow velocity increased, the small droplets were more entrained to the upper and central parts of the spray and this tendency was confirmed by plotting the temporal velocity profile of droplets. This entrainment of small droplets at high airflow velocities caused relatively small mean droplet size at upper and central parts of the spray and the large mean droplet size at downstream and edge of the spray, compared to that of low airflow velocities. The total mean droplet size, obtained by averaging the size of all droplets measured at all test locations, decreased when the high airflow velocities were applied. The increased fuel temperature, with an airflow velocity of 10m/s, caused reduced droplet size at all test locations. However, the decreased value of mean droplet size at high fuel temperatures was relatively higher at upper parts of the spray, compared to downstream, as a result of enhanced entrainment of small droplets to upper parts of the spray.
Numerical Simulation of Thermal Lattice Boltzmann Model with a Modified In-Ternal Energy Non-Equilibrium First-Order Extrapolation Boundary Condition
Jeong, Hae-Kwon ; Kim, Lae-Sung ; Lee, Hyun-Goo ; Lee, Jae-Ryong ; Ha, Man-Yeong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 620~627
DOI : 10.3795/KSME-B.2007.31.7.620
In this paper, we adapt a modified internal energy non-equilibrium first-order extrapolation thermal boundary condition to the thermal lattice Boltzmann model (TLBM). This model is the double populations approach to simulate hydrodynamic and thermal fields. The bounce-back boundary condition which is a traditional boundary condition of lattice Boltzmann method has only a first order in numerical accuracy at the boundary and numerical instability. A non-equilibrium first-order extrapolation boundary condition has been verified to be of better numerical stability than the bounce-back boundary condition and this boundary condition is proved to be of second-order accuracy for the flat boundaries. The two-dimensional natural convection flow in a square cavity with Pr=0.71 and various Rayleigh numbers are simulated. The results are found to be in good agreement with those of previous studies.
Detailed Measurement of Heat/Mass Transfer in a Rotating Equilateral Triangular Channel with Smooth Walls
Kim, Kyung-Min ; Lee, Dong-Hyun ; Cho, Hyung-Hee ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 628~634
DOI : 10.3795/KSME-B.2007.31.7.628
The present study investigated the heat/mass transfer characteristics in an equilateral triangular channel simulating the leading edge cooling passage in gas turbine blade. Using naphthalene sublimation method and pressure measurement experiments, local mass (heat) transfer and pressure coefficients were obtained. The experiments were conducted with three rotating numbers between 0.0 and 0.1; two channel orientations of
(model A) and
(model B); the fixed Reynolds number of 10,000. The results showed that the channel rotation caused the heat transfer discrepancy between suction and pressure sides. Due to the secondary flow induced by Coriolis force, the high heat transfer appeared on the pressure side. When the channel orientation was
(model B), the secondary flow caused the more uniform heat transfer distribution among leading edge and inner wall on pressure side than that of the model A.
A Study on Inverse Radiation Analysis using RPSO Algorithm
Lee, Kyun-Ho ; Kim, Ki-Wan ; Kim, Man-Young ; Baek, Seung-Wook ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 635~643
DOI : 10.3795/KSME-B.2007.31.7.635
An inverse radiation analysis is presented for the estimation of the radiation properties for an absorbing, emitting, and scattering media with diffusely emitting and reflecting opaque boundaries. In this study, a repulsive particle swarm optimization(RPSO) algorithm which is a relatively recent heuristic search method is proposed as an effective method for improving the search efficiency for unknown parameters. To verify the performance of the proposed RPSO algorithm, it is compared with a basic particle swarm optimization(PSO) algorithm and a hybrid genetic algorithm(HGA) for the inverse radiation problem with estimating the various radiation properties in a two-dimensional irregular medium when the measured temperatures are given at only four data positions. A finite-volume method is applied to solve the radiative transfer equation of a direct problem to obtain measured temperatures.
Simultaneous Measurement of Velocity and Temperature Fields in Micro-Scale Flow and Its Application to Electrokinetic Flow
Lee, Beom-Joon ; Jin, Song-Wan ; Kim, Young-Won ; Yoo, Jung-Yul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 7, 2007, Pages 644~652
DOI : 10.3795/KSME-B.2007.31.7.644
In this paper, a technique of simultaneously measuring the velocity and the temperature in micro-scale flow is proposed. This method uses particle tracking velocimetry (PTV) for measuring the velocity and laser induced fluorescence (LIE) for measuring the temperature. To measure the accurate velocity and temperature, images for PTV and for LIE are separated by using two light sources and a shutter which is synchronized with a camera. By using only one camera, measurement system can be simplified and the error from complicate optical system can be minimized. Error analyses regarding the concentrations of fluorescent dye and particle and the light source fluctuation are also conducted. It is found that the error of the temperature and the velocity highly depends on the concentration of fluorescent particles which are used for PTV. This technique is applied to the simultaneous measurement of the velocity and the temperature in the electrokinetic flow. It is found that the velocity and temperature vary with the electric field strength and the concentration of electrolyte.