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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 38, Issue 12 - Dec 2014
Volume 38, Issue 11 - Nov 2014
Volume 38, Issue 10 - Oct 2014
Volume 38, Issue 9 - Sep 2014
Volume 38, Issue 8 - Aug 2014
Volume 38, Issue 7 - Jul 2014
Volume 38, Issue 6 - Jun 2014
Volume 38, Issue 5 - May 2014
Volume 38, Issue 4 - Apr 2014
Volume 38, Issue 3 - Mar 2014
Volume 38, Issue 2 - Feb 2014
Volume 38, Issue 1 - Jan 2014
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Numerical Study of Wavy Film Flow on Vertical Plate Using Different Turbulent Models
Min, June Kee ; Park, Il Seouk ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 373~380
DOI : 10.3795/KSME-B.2014.38.5.373
Film flows applied to shell-and-tube heat exchangers in various industrial fields have been studied for a long time. One boundary of the film flow interfaces with a fixed wall, and the other boundary interfaces with a gaseous region. Thus, the flows become so unstable that wavy behaviors are generated on free surfaces as the film Reynolds number increases. First, high-amplitude solitary waves are detected in a low Reynolds number laminar region; then, the waves transit to a low-amplitude, high frequency ripple in a turbulent region. Film thickness is the most significant factor governing heat transfer. Since the wave accompanied in the film flow results in temporal and spatial variations in film thickness, it can be of importance for numerically predicting the film's wavy behavior. In this study, various turbulent models are applied for predicting low-amplitude ripple flows in turbulent regions. The results are compared with existing experimental results, and finally, the applied turbulent models are appraised in from the viewpoint of wavy behaviors.
Visualization Study of the Floating Body Behavior in a Short-Distance Wave Maker
Kim, Se-Young ; Lim, Hee-Chang ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 381~388
DOI : 10.3795/KSME-B.2014.38.5.381
Our aim was to simulate ocean waves in a small-size wave flume and observe the motion of a cylindrical floating body placed in an offshore environment. To precisely visualize the oscillation of the body, a set of light-emitting diode illuminators and high-speed charge-coupled device camera were installed in the flume. Spectral analysis was performed of the movement of the floating body. The wave generator and absorbers worked well to simulate stable regular waves. As the period of the oncoming waves changed, the movement of the floating body substantially differed when tethered to a tension-leg mooring cable. In particular, when connected to the tension-leg mooring cable, the natural frequency of the floating body suddenly appeared at 0.391 Hz as the wave period was increased.
Experimental Study on the Dependence of Variation in Performance of a High-Temperature Generator on Its Operating Conditions
Bae, Kyungjin ; Kwak, Myoungseok ; Cho, Honghyun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 389~397
DOI : 10.3795/KSME-B.2014.38.5.389
An absorption chiller-heater using only a natural refrigerant hardly causes any environmental pollution. In an absorption chiller-heater, the performance of its high-temperature generator, which uses exhaust gases, is essential to achieving superior system performance. To investigate the performance of such a high-temperature generator, a laboratory-scale high-temperature generator working with exhaust gases was designed and tested. Changes in the performance of the high-temperature generator as a function of inlet conditions of the absorbing solution, such as air inlet temperature and mass flow, were investigated. It was observed that when the air mass flow rate ratio was increased from 80% to 120%, the heat capacity was increased by 30%, 33%, 34%, and 37%, respectively. Additionally, when the air inlet temperature was elevated from
for absorption solution concentrations of 56%, 55%, 545, and 53%, the heat capacity increased by 140%, 160%, 220%, and 224%, respectively.
Three-Dimensional Flow and Aerodynamic Loss in the Tip-Leakage Flow Region of a Turbine Blade with Pressure-Side Winglet and Suction-Side Squealer
Cheon, Joo Hong ; Kang, Dong Bum ; Lee, Sang Woo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 399~406
DOI : 10.3795/KSME-B.2014.38.5.399
Three-dimensional flow and aerodynamic loss in the tip-leakage flow region of a turbine blade equipped with both a pressure-side winglet and a suction-side squealer have been measured for the tip gap-to-span ratio of h/s = 1.36%. The suction-side squealer has a fixed height-to-span ratio of
= 3.75% and the pressure-side winglet has width-to-pitch ratios of w/p = 2.64%, 5.28%, 7.92% and 10.55%. The results are compared with those for a plane tip and for a cavity squealer tip of
= 3.75%. The present tip delivers lower loss in the passage vortex region but higher loss in the tip-leakage vortex region, compared to the plane tip. With increasing w/p, its mass-averaged loss tends to be reduced. Regardless of w/p, the present tip provides lower loss than the plane tip but higher loss than the cavity squealer tip.
Novel Apparatus for Seawater Desalination and Its Application
Lee, Ju Dong ; Kang, Kyung Chan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 407~412
DOI : 10.3795/KSME-B.2014.38.5.407
A new apparatus for seawater desalination, based on the principle of gas hydrates, is suggested. The equipment continuously produces and pelletizes gas hydrates by a squeezing operation in a dual cylinder unit, which is able to extract pure hydrate pellets from the seawater-containing reactor. Desalination efficiency for each dissolved ion from seawater samples was tested by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and ion chromatography (IC) analysis. This study demonstrates that the suggested method and the stated apparatus may solve the difficulty of separating hydrate crystals from concentrated brine solutions, and therefore may be applied to improve the efficiency of existing desalination processes.
A Study on Cooling Performance and Exergy Analysis of Desiccant Cooling System in Various Regeneration Temperature and Outdoor Air Conditions
Lee, Jang Il ; Hong, Seok Min ; Byun, Jae Ki ; Choi, Young Don ; Lee, Dae Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 413~421
DOI : 10.3795/KSME-B.2014.38.5.413
Desiccant cooling system is an air conditioning system that uses evaporative cooler to cool air and it can perform cooling by using heat energy only without electrically charged cooler. Thus, it can solve many problems of present cooling system including the destruction of ozone layer due to the use of CFC[chloro fluoro carbon] affiliated refrigerants and increase of peak power during summer season. In this study, cooling performance and exergy analysis was conducted in order to increase efficiency of desiccant cooling system. Especially, using exergy analysis based on the second law of thermodynamics can resolve the issue related to system efficiency in a more fundamental way by analyzing the cause of exergy destruction both in whole system and each component. The purpose of this study is to evaluate COP[coefficient of performance], cooling capacity and exergy performance of desiccant cooling system incorporating a regenerative evaporative cooler in various regeneration temperature and outdoor air conditions.
Effect of the Inner Material and Pipe Geometry on the Flow and Induced Radiated Noise
Lee, Su-Jeong ; Lim, Hee-Chang ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 423~430
DOI : 10.3795/KSME-B.2014.38.5.423
Noise and vibration, which occur in a pipe, are usually caused by the interaction between the turbulent flow and nearby wall. Although it can be estimated by a simple case of expanded pipes having complex turbulent flow, the radiated noise is highly dependent upon the size, shape, and thickness of the given model. In addition, the radiated noise propagates and has serious interference and destabilization effects on the surrounding systems, which can lead to fatigue fracture and failure. This study took advantage of the variety of commercial programs, such as FLUENT (flow solver), NASTRAN (dynamic motion solver of complex structures) and VIRTUAL LAB (radiated noise solver) based on the boundary element method (BEM), to understand the underlying physics of flow noise. The expanded pipe has separation and a high pressure drop because of the abrupt change in the cross-section. Based on the radiated noise calculations, the noise level was reduced to around 20 dB in the range of 100-500 Hz.
Flow Rate Prediction of Pneumatic Pipe System Using Concept of Conductance
Kim, Jin-Hyeon ; Deng, Ruoyu ; Kim, Heuy-Dong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 431~436
DOI : 10.3795/KSME-B.2014.38.5.431
Conductance is a concept contrary to flow resistance and is extensively used as a flow index on how easily fluid is transported through a pneumatic pipe or fluid device. However, research on flow conductance is very rare to date, and a systematic investigation is needed for the standardization of pneumatic devices. In the present study, a computational fluid dynamics method was applied to solve the compressible Navier-Stokes equations with two-equation turbulence models. The present CFD results were validated with existing experimental data. The conductance values and friction factors at the inlet and outlet of a pneumatic pipe were used to assess the flow rates. The present results showed that the conductance depends on the pressure ratio at the inlet and outlet of a pipe.
Energy Harvesting from Reverse Electrodialysis in Ion-Selective Membrane Formed with Self-Assembled Nanoparticles
Choi, Eunpyo ; Kwon, Kilsung ; Kim, Daejoong ; Park, Jungyul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 38, issue 5, 2014, Pages 437~441
DOI : 10.3795/KSME-B.2014.38.5.437
This paper presents a novel microplatform for high power generation based on reverse electrodialysis. The ideal cation-selective membrane for power generation was realized using geometrically controlled in situ self-assembled nanoparticles. Our proposed membranes can be constructed through a simple and cost-effective process that uses microdroplet control with nanoparticles in a microchannel. Another advantage of our system is that the maximum power and energy conversion efficiency can be improved by changing the geometry of the microchannel and proper selection of the nanoparticle size and material. This proposed platform can be used to supply power sources to other microdevices and contribute to a fundamental understanding of ion transport behavior and the power generation mechanism.