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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
Remaining Useful Life Prediction of Li-Ion Battery Based on Charge Voltage Characteristics
Sim, Seong Heum ; Gang, Jin Hyuk ; An, Dawn ; Kim, Sun Il ; Kim, Jin Young ; Choi, Joo Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 313~322
DOI : 10.3795/KSME-B.2013.37.4.313
Batteries, which are being used as energy sources in various applications, tend to degrade, and their capacity declines with repeated charging and discharging cycles. A battery is considered to fail when it reaches 80% of its initial capacity. To predict this, prognosis techniques are attracting attention in recent years in the battery community. In this study, a method is proposed for estimating the battery health and predicting its remaining useful life (RUL) based on the slope of the charge voltage curve. During this process, a Bayesian framework is employed to manage various uncertainties, and a Particle Filter (PF) algorithm is applied to estimate the degradation of the model parameters and to predict the RUL in the form of a probability distribution. Two sets of test data-one from the NASA Ames Research Center and another from our own experiment-for an Li-ion battery are used for illustrating this technique. As a result of the study, it is concluded that the slope can be a good indicator of the battery health and PF is a useful tool for the reliable prediction of RUL.
Simulation of Woody Leaf Netted Venation Based on Optimization Technique
Chen, Lei ; Li, Weizheng ; Jang, Gang Won ; Baek, Tae Hyun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 323~329
DOI : 10.3795/KSME-B.2013.37.4.323
This study attempts to simulate the structure of a woody leaf netted venation system by using topology optimization techniques. Based on finite element method (FEM) analysis of an incompressible fluid, a topology optimal design is applied to those woody leaf netted venation models. To solve the transverse shear locking problem of a thin plate caused by the Mindlin-Reissner plate model where a leaf netted venation is assumed to be a thin plate, a P1-nonconforming element and selective reduced integration are employed. Topology optimal design is applied to multiple physical domains. Combined with the Darcy-Stokes flow problems and extended to the optimal design of fluid channels, the multiple physical models of the flow system are analyzed and venation patterns of leafs are simulated. The calculated optimal shapes are compared with the natural shapes of woody leaf venation patterns. This interdisciplinary approach may improve our understanding of the leaf venation system.
Computational Fluid Dynamics Model for Solar Thermal Storage Tanks with Helical Jacket Heater and Upper Spiral Coil Heater
Baek, Seung Man ; Zhong, Yiming ; Nam, Jin Hyun ; Chung, Jae Dong ; Hong, Hiki ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 331~341
DOI : 10.3795/KSME-B.2013.37.4.331
In a solar domestic hot water (SDHW) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (TST) as hot water. In this study, a computational fluid dynamics (CFD) model was developed to predict the solar thermal energy storage in a hybrid-type TST equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a TST, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the TST. The developed model was validated by the good agreement between the CFD results and the experimental results performed with the hybrid-type TST in SDHW settings.
Study of Pool Boiling Heat Transfer on Various Surfaces with Variation of Flow Velocity
Kang, Dong-Gyu ; Lee, Yohan ; Seo, Hoon ; Jung, Dongsoo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 343~352
DOI : 10.3795/KSME-B.2013.37.4.343
In this study, a smooth flat surface, low fin, Turbo-B, and Thermoexcel-E surfaces are used to examine the effect of the flow velocity on the pool boiling heat transfer coefficients (HTCs) and critical heat fluxes (CHFs). HTCs and CHFs are measured on a smooth square heater of
in a pool of pure water at various fluid velocities of 0, 0.1, 0.15, and 0.2 m/s. Test results show that for all surfaces, CHFs obtained with flow are higher than those obtained without flow. CHFs of the low fin surface are higher than those of the Turbo-B and Thermoexcel-E surfaces due largely to the increase in surface area and sufficient fin spaces for the easy removal of bubbles. CHFs of the low fin surface show even 5 times higher CHFs as compared to the plain surface. On the other hand, both Turbo-B and Thermoexcel-E surfaces do not show satisfactory results because their pore sizes are too small and water bubbles easily cover them. At low heat fluxes of less than
, HTCs increase as the flow velocity increases for all surfaces. In conclusion, a low fin geometry is good for application to steam generators in nuclear power plants.
Study on Ohmic Resistance of Polymer Electrolyte Fuel Cells Using Current Interruption Method
Ji, Sanghoon ; Hwang, Yong-Sheen ; Lee, Yoon Ho ; Park, Taehyun ; Paek, Jun Yeol ; Chang, Ikwhang ; Cha, Suk Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 353~358
DOI : 10.3795/KSME-B.2013.37.4.353
The current interruption method is considered to be an efficient way of measuring the resistance of a fuel cell. In this study, the ohmic area specific resistances (ASRs) of polymer electrolyte fuel cells with different types of bipolar plates were evaluated using the current interruption method. The ohmic ASRs of both a fuel cell with graphite bipolar plates and a fuel cell with graphite foil-based assembled bipolar plates decreased as the current density increased. On the other hand, with increasing cell temperature, the ohmic ASRs of a fuel cell with graphite bipolar plates were decreased by a reduction in the proton transport resistance through the membrane, and the ohmic ASRs of a fuel cell with graphite foil-based assembled bipolar plates were increased by the differences in thermal expansion between different components of the bipolar plates.
Study on Characteristics of Flow-Induced Vibrations of Two Circular Cylinders
Kim, Sang Il ; Lee, Seung Chul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 359~366
DOI : 10.3795/KSME-B.2013.37.4.359
This study aims to investigate the characteristics of the flow-induced vibrations of two circular cylinders. The characteristics of the flow-induced vibrations are examined for various flow velocities and spaces between the two cylinders when they are arranged in tandem, staggered, and side-by-side positions. The results are as follows: (i) Seven flow-induced vibration patterns are observed when the two circular cylinders are placed in either tandem, staggered, or side-by-side positions. (ii) The two cylinders induce a vibration because they affect each other. (iii) The easiest way to induce a vibration of the two cylinders is by placing them in the side-by-side position among the three arrangements (tandem, staggered, and side-by-side). (iv) The change in the maximum flow-induced vibration of the two cylinders depends strongly on the fluctuating lift forces of each of them.
Numerical Analysis for Heat Transfer Characteristics of Elliptic Fin-Tube Heat Exchanger with Various Shapes
Yoo, Jae Hwan ; Yoon, Jun Kyu ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 367~375
DOI : 10.3795/KSME-B.2013.37.4.367
In this study, the characteristics of the heat transfer coefficient and pressure drop were numerically analyzed according to the axis ratio (AR), pitch, location of vortex generator, and bump phase of the tube surface about an elliptical fin-tube heat exchanger. The boundary condition for CFD analysis was decided as a tube surface temperature of 348 K and inlet air velocity of 1-5 m/s. RSM 7th turbulent model was chosen as the numerical analysis for the sensitivity level. The analysis results indicated that the AR and transverse pitch decreased whereas the heat transfer coefficient increased. On the other hand, there was little difference in the longitudinal pitch. Furthermore, the heat transfer rate was more favorable when the vortex generator was located in front of the tube. Also, the bump phase of the tube surface indicated that the pressure drop and heat transfer were more favorable with the circle type than with the serrated type.
Effects of Outflow Area on Pool Boiling in Vertical Annulus
Kang, Myeong-Gie ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 377~385
DOI : 10.3795/KSME-B.2013.37.4.377
To identify the effects of an outflow area on pool boiling heat transfer in a vertical annulus, three different flow restrictors were studied experimentally. For the test, a heated tube of smooth stainless steel and water at atmospheric pressure were used. Both annuli with open and closed bottoms were considered. To validate the effects of the outflow area on the heat transfer, the results of the annulus with the restrictor were compared with the data for the plain annulus without the restrictor. The reduction of the outflow area ultimately results in a decrease in the heat transfer. As the outflow area is very small, a slight increase in heat transfer is also observed. The major cause of this tendency is explained as the difference in the intensity of liquid agitation cause by the movement of coalesced bubbles. It is identified that the convective flow, pulsating flow, and evaporative mechanism are considered as the important mechanisms.
Study of Performance and Knock Characteristics with Compression Ratio Change in HCNG Engine
Lim, Gi Hun ; Lee, Sung Won ; Park, Cheol Woong ; Choi, Young ; Kim, Chang Gi ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 387~394
DOI : 10.3795/KSME-B.2013.37.4.387
Hydrogen-compressed natural gas (HCNG) blend has attracted attention as a fuel that can reduce
emissions because it has low carbon content and burns efficiently. An increase in the compression ratio of HCNG engines was considered as one of the methods to improve their efficiency and reduce
emissions. However, a high combustion rate and flame temperature cause abnormal combustion such as pre-ignition or knocks, which in turn can cause damage to the engine components and decrease the engine power. In this study, the performance and knock characteristics with a change in the compression ratio of an HCNG engine were analyzed. The combustion characteristics of HCNG fuel were evaluated as a function of the excess air ratio using a conventional CNG engine. The effects of the compression ratio on the engine performance were evaluated through the same experimental procedures.
Effect of Aspect Ratio of Flat Tube on R410A Evaporation Heat Transfer and Pressure Drop
Kim, Nae Hyun ; Lee, Eul Jong ; Byun, Ho Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 395~404
DOI : 10.3795/KSME-B.2013.37.4.395
In this study, R-410A evaporation heat transfer tests were conducted in flattened tubes made from 5-mm round tubes. The test range covered a saturation temperature of
, heat flux of
, and mass flux of
. The results showed that both the condensation heat transfer coefficient and the pressure drop increased as the aspect ratio increased, with a pronounced increase for an aspect ratio of 4. A comparison of the flattened tube data with existing correlations revealed that the heat transfer coefficients were reasonably predicted by the Shah correlation, and the pressure drops were reasonably predicted by the Jung and Radermacher correlation.
Char Oxidation Characteristics of High Ash Coal in Drop Tube Furnace
An, Ke-Ju ; Lee, Byoung-Hwa ; Kim, Sang-In ; Kim, Man-Cheol ; Kim, Seung-Mo ; Jeon, Chung-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 405~413
DOI : 10.3795/KSME-B.2013.37.4.405
The char oxidation characteristics of high ash coal were experimentally investigated at several temperatures (from 900 to
) for 4 types of coals (Gunvor, Glencore, Noble, and ECM) under atmospheric pressure in a drop tube furnace (DTF). The char reaction rate was calculated from the exhaust gas concentrations (CO and
) using FT-IR, and the particle temperature was measured using the two-color method. In addition, the activation energy and pre-exponential factor for high ash coal char were calculated based on the Arrhenius equation. The results show that as the ash content increases, the particle temperature and area reactivity decreases. This is because in high ash coal, the large heat capacity of the ash, ash vaporization, and relatively low fixed carbon content of ash suppress combustibility during char oxidation. As a result, the higher ash content of coal leads to high activation energy.
Axial Turbine Aerodynamic Design of Small Heavy-Duty Gas Turbines
Kim, Joung Seok ; Lee, Wu Sang ; Ryu, Je Wook ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 415~421
DOI : 10.3795/KSME-B.2013.37.4.415
This study describes the aerodynamic design procedure for the axial turbines of a small heavy-duty gas turbine engine being developed by Doosan Heavy Industries. The design procedure mainly consists of three parts: namely, flowpath design, airfoil design, and 3D performance calculation. To design the optimized flowpath, through-flow calculations as well as the loss estimation are widely used to evaluate the effect of geometric variables, for example, shape of meridional plane, mean radius, blades axial gap, and hade angle. During the airfoil design procedure, the optimum number of blades is calculated by empirical correlations based on the in/outlet flow angles, and then 2D airfoil planar sections are designed carefully, followed by 2D B2B NS calculations. The designed planar sections are stacked along the spanwise direction, leading to a 3D surfaced airfoil shape. To consider the 3D effect on turbine performance, 3D multistage Euler calculation, single row, and multistage NS calculations are performed.
Performance Prediction of Wind Power Turbine by CFD Analysis
Kim, Jong-Ho ; Kim, Jong-Bong ; Oh, Young-Lok ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 4, 2013, Pages 423~429
DOI : 10.3795/KSME-B.2013.37.4.423
The performance of a vertical-type wind power generator system was predicted by CFD analysis. In the analysis, the reaction torque was calculated for a given rotational speed of the blades. The blade torque of a wind power system was obtained for various rotational speeds, and the generation power was calculated using the obtained torque and the rotational speed. The optimum generator specification, therefore, could be decided using the relationship between the generated power and the rotational speeds. The effects of the number of blades and blade shapes on the generation power were also investigated. Finally, the analysis results were compared with the experimental results.