Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Transactions of the Korean Society of Mechanical Engineers B
Journal Basic Information
Journal DOI :
The Korean Society of Mechanical Engineers
Editor in Chief :
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
Experimental Study of Adoption of Alternative Refrigerant for Avionic Equipment Cooling System
Kang, Hoon ; Jung, Jongho ; Jung, Minwoo ; Chi, Yongnam ; Yoo, Yongseon ; Choi, Heeju ; Byeon, Youngman ; Kim, Youngjin ; Oh, Kwangyoon ; Kim, Yongchan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 431~439
DOI : 10.3795/KSME-B.2013.37.5.431
A cooling system is adopted to control the thermal load from the avionic equipments in an aircraft for stable operation. In this study, an avionic cooling system was designed and manufactured by adopting a vapor compression cycle with a closed-loop air-circulation system to investigate the operating characteristics of an alternative refrigerant. The performance characteristics of a cooling system adopting R236fa as an alternative refrigerant were experimentally determined by varying the refrigerant charging amount, expansion valve opening, and compressor rotation speed. The experimental results were analyzed and compared with those of a cooling system adopting R124 as a refrigerant. The possibility of the adoption of R236fa as an alternative refrigerant was verified, and design solutions were suggested to improve the system efficiency.
Algorithm and Implementation of Fast Multipole Boundary Element Method with Theoretical Analysis for Two-Dimensional Heat Conduction Problems
Choi, Chang-Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 441~448
DOI : 10.3795/KSME-B.2013.37.5.441
This paper presents the fast multipole boundary element method (FM-BEM) as a new BEM solution methodology that overcomes many disadvantages of conventional BEM. In conventional BEM, large-scale problems cannot be treated easily because the computation time increases rapidly with an increase in the number of boundary elements owing to the dense coefficient matrix. Analysis results are obtained to compare FM-BEM with conventional BEM in terms of computation time and accuracy for a simple two-dimensional steady-state heat conduction problem. It is confirmed that the FM-BEM solution methodology greatly enhances the computation speed while maintaining solution accuracy similar to that of conventional BEM. As a result, the theory and implementation algorithm of FM-BEM are discussed in this study.
Study of Blood Characteristics in Stenosed Artery under Human Body Rotation by Using FSI Method
Cho, Seong Wook ; Kim, Seungwook ; Ro, Kyoung Chul ; Ryou, Hong Sun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 449~457
DOI : 10.3795/KSME-B.2013.37.5.449
In this study, we performed a numerical analysis to investigate the effect of rotation on the blood flow and arterial wall behavior by using the FSI (fluid-structure interaction) technique. The geometry of the artery included 50% stenosis at the center. To simulate the rotational effect, 2-6 rps of axial velocity was applied to the arterial model. A spiral wave and asymmetric flow occurred due to the stenosis and axial rotation both in the rigid body model and in the FSI model. However, the arterial wall motion caused periodic and transient blood flow changes in the FSI model. The FRZ (fluid recirculation zone) decreased in the FSI model, which is a known predictor for the formation and vulnerability of plaque. Therefore, it is observed that arterial wall motion also influences the generation of the FRZ.
Study for Effect of Changes in Thermal Properties on Cooling Process in Running Hot Steel Strip After Hot Rolling
Park, Il Seouk ; Park, Jung Eun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 459~465
DOI : 10.3795/KSME-B.2013.37.5.459
In the manufacturing process of steel plates, materials at high temperatures above
are rapidly cooled by using a circular impinging water jet to determine their strength and toughness. In this study, the basic heat and fluid flow is solved by using the existing numerical model for boiling heat transfer. Actually, steel undergoes a phase change from austenite to ferrite or bainite during the cooling process. The phase change induces changes in its thermal properties. Instead of directly solving the phase change and the material cooling together, we solve the heat transfer only by applying the thermal properties that vary with temperature, which is already known from other studies. The effects of the changes in the thermal properties on the cooling of steel and the necessity of calculating the phase change are discussed.
Studies on Raw-Water Source Heat Pump Equipped with Thermal Storage Tank in Water Treatment Facility
Oh, Sun Hee ; Yun, Rin ; Cho, Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 467~472
DOI : 10.3795/KSME-B.2013.37.5.467
A raw-water source heat pump equipped with a thermal storage tank was dynamically simulated by TRNSYS, and the results were verified by using the data from a heat pump installed in the Seongnam water treatment facility. The average coefficient of performance (COP) of the raw-water source heat pump based on simulation was 4.97 and 3.17 in the cooling and heating season, respectively. When the volume of the thermal storage tank was changed from 5 to
, the highest COP was found at a size of
. Considering the regional locations of raw-water source heat pumps at Seoul, Incheon, Gangneung, and Gwangju, Seoul showed the lowest electric power consumption in the cooling season and the highest in the heating season. When a comparison of the performance between the present system and that of a water-air heat pump was conducted, the present system showed lower electric power consumption by 25% than that of a water-air heat pump.
Effect of Compression Ratio Change on Emission Characteristics of HCNG Engine
Lee, Sung Won ; Lim, Gi Hun ; Park, Cheol Woong ; Choi, Young ; Kim, Chang Gi ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 473~479
DOI : 10.3795/KSME-B.2013.37.5.473
This study focused on a heavy-duty natural gas engine fuelled with HCNG (CNG: 70 vol%, hydrogen: 30 vol%) and CNG. To study the emission characteristics of an HCNG engine with high compression ratio, the exhaust gas of CNG and HCNG fuel were analyzed in relation to the change in the compression ratio at the half load condition. The results showed that the thermal efficiency improved with an increase in the compression ratio. Consequently,
emission decreased. CO emission increased with inefficient oxidation due to the low exhaust gas temperature.
emission with high compression ratio was increased at the same excess air ratio condition. However,
emission was not affected by a compression ratio exceeding
= 1.9 because of the same MBT timing.
Comparison of Fuel-NO
Formation Characteristics in Conventional Air and Oxyfuel Combustion Conditions
Woo, Mino ; Park, Kweon Ha ; Choi, Byung Chul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 481~488
DOI : 10.3795/KSME-B.2013.37.5.481
Nitric oxide (
) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of coflow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the
emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the
emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the
emission in the condition of oxyfuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of
formation for various oxidizer compositions, 1D and 2D numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2D simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured
Shape Oscillation and Mode Characteristic of Droplet on Vibrating Flat Surface
Shin, Young-Sub ; Lim, Hee-Chang ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 489~494
DOI : 10.3795/KSME-B.2013.37.5.489
This study aims to understand the mode characteristics of a droplet under a periodic forced vibration. To predict the resonance frequency of a droplet, theoretical and experimental approaches were employed. A high-speed camera was used to capture the various deformation characteristics of a droplet-mode shape, detachment, separated secondary droplet, and skewed deformation. The comparison between the theoretical and the experimental approaches shows a ~10% discrepancy in the prediction of the resonance frequency, which appears to be caused by the effect of contact line friction, nonlinear wall adhesion, and experimental uncertainty. Owing to contact-line pinning and smaller amplitude, the droplet shape becomes symmetric and the size of each lobe at the resonance frequency exceeds that at the neighbor, which is out of resonance.
Wireless Telemetry of an Oscillating Flow using Mesoscale Flexible Cantilever Sensor
Park, Byung Kyu ; Lee, Joon Sik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 495~501
DOI : 10.3795/KSME-B.2013.37.5.495
This paper describes a flexible wireless telemetering system using a mesoscale cantilever sensor, which is microfabricated with a patterned thin Ni-Cu foil on a resin substrate. The dynamic validation of the sensor has been conducted in a flow. The wireless telemetry is used to obtain data regarding the oscillating flows. It is shown that the sensor is nearly independent of the environmental temperature and is suitable for application to primary healthcare and diagnostic devices. It can be easily integrated with other modules for measuring physiological parameters, e.g., blood pressure, oxygen saturation, and heart rate, to increase the convenience and reliability of diagnosis. The precision and reliability of the sensor are also dependent on the design of the analog front-end and noise reduction techniques. It is shown that the present system's minimum interval between packet transmissions is ~16 ms.
Numerical Study of Characteristic of Heat and Mass Transfer in Planar Membrane Humidifier According to Flow Direction
Yun, Sungho ; Byun, Jae Ki ; Choi, Young Don ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 503~511
DOI : 10.3795/KSME-B.2013.37.5.503
The humidifying supply gas is important in terms of the performance efficiency and membrane life improvement of a PEM fuel cell. A planar membrane humidifier is classified as a cross-flow and counter-flow type depending on the flow direction, and heat and mass transfer occur between the plate and the membrane. In this study, the changes in heat and mass transfer for various inlet temperatures and flow rates are compared according to the flow direction by using the sensible and latent
-NTU method. The obtained results indicate that the counter flow shows higher heat and mass transfer performance than the cross flow at a low flow rate, and the difference in performance decreases as the flow rate increases. Furthermore, changes in the mass transfer performance decrease considerably with a nonlinear increase in the inlet temperature, and variations of the heat transfer performance are small.
3D Numerical Study of Horizontal Falling Film Evaporator in Multi Effect Distillation (MED) Plant
Kim, Soo Jae ; Je, Junho ; Kim, Moo Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 513~522
DOI : 10.3795/KSME-B.2013.37.5.513
In the present work, a numerical study of a horizontal falling film evaporator in a multi-effect distillation (MED) plant is performed. Tube bundles in the evaporator are described as porous media, and a volume-averaged method is applied. To calculate the fluid flow and phase change in the evaporator due to heat transfer in the system, FLUENT and user-defined functions (UDF) are used. To observe the performance of the evaporator under different operational conditions, tests are conducted for a steam mass flux ranging from 0.5 to 2.5
in the horizontal tube, for mass fraction of the noncondensable gas in the tube inlet ranging from 0% to 1%, and for film Reynolds numbers ranging from 100 to 1,000 for the falling film. The evaporation rate increases with the steam mass flux and Reynolds number. In contrast, the evaporation rate decreases by 0.87% with a 1% increase in the mass fraction of the noncondensable gas in the tube.
Numerical Study of Surface Heat Transfer Effects of Multiple Fan-Shaped Small-Scale Fins
Park, Ki-Hong ; Park, Sang Hu ; Lee, Ju-Chul ; Min, June-Kee ; Ha, Man-Yeong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 523~530
DOI : 10.3795/KSME-B.2013.37.5.523
In this work, we study a heat transfer enhancement technology using fan-shaped small-scale fins. Fins having a thickness of 10
move up-down by a pulsating flow. Owing to these motions, the heat transfer on a surface increases dramatically. The two-way FSI (fluid-structure interaction) method was applied for the analysis, and the analysis model was evaluated using a single fin model by comparing the experimental results. In summary, a maximum 40% increase in heat transfer capacity using a single and multiple small-scale fins was obtained in comparison with the results obtained without using fins. From this work, we believe that the proposed method can be a promising method for heat transfer enhancement in real applications.
Flow Field in Volute for Various Operating Conditions of Centrifugal Compressor
Kang, Kyung Jun ; Shin, You Hwan ; Kim, Kwang Ho ; Lee, Yoon Pyo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 5, 2013, Pages 531~538
DOI : 10.3795/KSME-B.2013.37.5.531
The primary function of centrifugal compressor volute is to flow from the impeller and diffuser to the pipe system. The strength of the scroll vortex and flow pattern in the volute vary with the operating point. This is largely caused by the interaction between the impeller and the volute flow fields. The recirculation flow around the tongue and the scroll vortex can be used to understand the characteristics of the volute flow at off-design points. The present study aims to find the characteristics of a flow pattern in the diffuser and volute of a centrifugal compressor from the rectangular cross section of the volute. Measurements are carried out using PIV. The results obtained in this study show that the separation region around the tongue is reduced and that the recirculation flow increases as the flow coefficient decreases.