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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
A Study About the Effect of EGR Ratio on DME HCCI Combustion Process
Lim, Ocktaeck ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 879~886
DOI : 10.3795/KSME-B.2013.37.10.879
This study aims to provide helpful suggestions for understanding the effect of high EGR on DME HCCI combustion. This study determined which between oxygen partial pressure and oxygen concentration was the main factor affecting the LTHR heating ratio. Furthermore, EGR and the supercharging effect were investigated. To define the parameters for the EGR ratio and supercharging pressure, a numerical analysis of the chemical reaction was conducted under the following conditions: (1) variation of EGR ratio, oxygen concentration, and oxygen content; (2) variation of oxygen partial pressure while the oxygen concentration was almost constant; and (3) variation of oxygen concentration while oxygen partial pressure was constant with EGR and supercharging. The results show that an increase in EGR reduces the combustion duration. On the other hand, an increase in boost pressure increases the combustion duration. Finally, the EGR and boost pressure affect the amount of increase in LTHR.
A Study on Prediction of Effective Thermal Conductivity of Nano-Fluids Using Generalized Self-Consistent Model and Modified Eshelby Model
Lee, Jae-Kon ; Kim, Jin Gon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 887~894
DOI : 10.3795/KSME-B.2013.37.10.887
Effective thermal conductivity of nanofluids has been predicted by using generalized self-consistent model and modified Eshelby model, which have been used for analysis of material properties of composites. A nanolayer between base fluid and nanoparticle, one of key factors for abrupt enhancement of thermal conductivity of nanofluids, is included in the analysis. The effective thermal conductivities of the nanofluid predicted by the present study show good agreement with those by models in the literature for the nanolayer with a constant or linear thermal conductivity. The predicted results by the present approach have been confirmed to be consistent with experiments for representative nanofluids such as base fluids of water or ethyleneglycol and nanoparticles of
or CuO to be validated.
Study on Stokes Flow Past Circular Cylinder in Two-Dimensional Channel
Yoon, Seok-Hyun ; Jeong, Jae-Tack ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 895~900
DOI : 10.3795/KSME-B.2013.37.10.895
A two-dimensional Stokes flow past a circular cylinder in a channel is analyzed. The circular cylinder is located at the center of the channel, and a plane Poiseuille flow exists upstream and downstream far from the circular cylinder. The Stokes approximation is used, and the flow is investigated analytically by using the eigenfunction expansion and the least square methods. From the analysis, the stream function and pressure distribution are obtained, and the pressure and shear stress distributions on the circular cylinder and channel wall are calculated. The additional pressure drop induced by the circular cylinder and the force exerted on it are calculated as functions of the length of the radius of the circular cylinder. For a typical length of the radius of the circular cylinder, the streamline pattern and pressure distribution are shown.
Investigation of Water Evaporation from Biomass with Different Torrefaction Environments
Go, Gun Yung ; Kim, Man Young ; Lee, Chang Yeop ; Kim, Sae Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 901~909
DOI : 10.3795/KSME-B.2013.37.10.901
Owing to the Increasing use of fossil fuels, worldwide concerns over environmental pollution are increasing. As a solution, ligneous biomass has emerged as a promising alternative fuel in recent times. Therefore, in this study, a moisture evaporation model that largely influences the energy density and efficiency of ligneous biomass is studied using a numerical approach. Furthermore, the thermal characteristics are analyzed in terms of torrefaction temperature and moisture fractions in the wood, and the type of wood species. The results show that the temperature and moisture fractions of wood decrease with an increase in the torrefaction temperature. In particular, when the torrefaction temperature is lower than 423K, there were little changes in the moisture fraction in the wood. Furthermore, it was found that charcoal is produced more slowly as the moisture fraction in the wood increases.
Numerical Study of Combustion Characteristics and NO Emission in Swirl Premixed Burner
Baek, Gwang Min ; Cho, Cheon Hyeon ; Cho, Ju Hyeong ; Kim, Han Seok ; Sohn, Chae Hoon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 911~918
DOI : 10.3795/KSME-B.2013.37.10.911
The combustion characteristics of an EV (Environmental Vortex) burner (double-cone burner) adopted in a gas turbines are numerically investigated. The mixing of fuel and air is analyzed for reduction of NO emission. To predict the correlation between NO emission and fuel-air mixedness, 1-step and 2-step chemistry models are adopted. The results calculated by 1-step chemistry showed that NO emissions increased by 2% in the case of degraded mixedness and by 169% in the case of improved mixedness, where the temperature in the flame zone was overestimated upstream of the cone. However, the corresponding results calculated by 2-step chemistry showed that NO emission increased by 3% and decreased by 5%, where the flame zone was not formed inside the cone. The latter results agree well with the experimental ones indicating an increase of 63% and decrease of 11% in the respective cases. Despite quantitative errors, NO emissions can be predicted reasonably by the application of the 2-step chemistry model adopted here and design modification of burner for NO reduction can be proposed based on the numerical data.
Development of Small-scale Organic Rankine Cycle System and Study on its Operating Characteristics
Yun, Eunkoo ; Kim, Hyun Dong ; Yoon, Sang Youl ; Kim, Kyung Chun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 919~926
DOI : 10.3795/KSME-B.2013.37.10.919
Experiments were conducted to determine the operating characteristics of a small-scale ORC (organic Rankine cycle) system for various low-temperature heat sources. A small-scale ORC power generation system adopting R-245fa as a working fluid was designed and manufactured. Hot water was used as the heat source, and the temperature was controlled using 110-kW electric resistance heaters that provided temperatures of up to
. An open-drive oil-free scroll expander directly connected to a synchronous generator was installed in the ORC unit. Experiments were conducted by varying the rotational speed of the expander under the same heat source temperature conditions. The factors that influence the performance of the small-scale ORC system were analyzed and discussed.
Computational Hemodynamics in the Intracranial Aneurysm Model
Seo, Taewon ; Byun, Jun Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 927~932
DOI : 10.3795/KSME-B.2013.37.10.927
The intracranial aneurysm model is extracted based on the Computed Tomography (CT) scan images. Computational fluid dynamics simulations were conducted under both steady and realistic flow conditions in ANSYS-FLUENT. The minimum wall shear stress in the intracranial aneurysm tended to occur in the aneurysmal region. The magnitude of wall shear stress along inner wall of the curvature in the right M1 segment of middle cerebral artery is approximately 20 times higher than that along both the proximal and distal walls. However, the magnitudes of the wall shear stress at the aneurysm region were considerably low. The blood flow has the complex distribution in the aneurysmal region during the systolic period. Complex helical flow patterns are observed inside the aneurysm. Through an analysis of the hemodynamic characteristics, one may predict the rupture of the cerebral aneurysms.
Perfonnance Evaluation of Swaged- and Extruded-type Heat Sinks Used in Inverter for Solar Power Generation
Kim, Jung Hyun ; Lee, Gyo Woo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 933~940
DOI : 10.3795/KSME-B.2013.37.10.933
In this study, we evaluated the heat release performance of two extruded-type and two swaged-type heat sinks used in an inverter for solar power generation. The number of fins and heat transfer areas of the two swaged-type heat sinks, namely S-62 and S-98, are 62 and 98 and
, respectively. Those for the two extruded-type heat sinks, namely, E-38 and E-47, are 38 and 47 and
, respectively. The heat release fractions of S-62 and S-98 were measured as 82.7 % and 86.3 %, respectively. Those of E-38 and E47 were measured to be 79.6 % and 81.6 %, respectively. In this experiment, despite the mass flow rates of air entering the heat sinks being almost the same, the heat release fractions increased with heat transfer area. Furthermore, despite S-62's heat transfer area being 47.4 % higher than that of E-47, its heat release fraction was higher by only 1.3 %. We believe that this indicates the better heat transfer property of the extruded-type heat sink. S-98's heat release is only 4.4 % higher than that of S-62, but its heat transfer area is 89.3 % higher; this suggests that its heat transfer area need to be optimized.
Numerical Study of Laminar Flow and Heat Transfer in Curved Pipe Flow
Kang, Changwoo ; Yang, Kyung-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 941~951
DOI : 10.3795/KSME-B.2013.37.10.941
A three dimensional numerical simulation of laminar flow and heat transfer in fully developed curved pipe flow has been performed to study the effects of Dean number and pipe curvature on the flow and temperature fields under the thermal boundary condition of axially uniform wall heat flux. The Reynolds number under consideration ranges from 100 to 4000, and the Prandtl number is 0.71. The curvature ratios are 0.01, 0.025, 0.05 and 0.1. The axial velocity and temperature profiles and the local Nusselt number obtained from the present study are in good agreement with the previous numerical and experimental results currently available. To show the effects of pipe curvature on the flow and heat transfer, the resistance coefficients and heat transfer coefficients are computed and compared with the results of the previous theoretical and experimental studies. The averaged Nusselt number is correlated with Dean and Prandtl numbers. Furthermore, the critical Reynolds number for transition to turbulent flow is observed to depend upon the curvature ratio.
Development of Multibody Dynamic Model of Cervical Spine for Virtual In Vitro Cadaveric Experiment
Lim, Dae Seop ; Lee, Ki Seok ; Kim, Yoon Hyuk ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 953~959
DOI : 10.3795/KSME-B.2013.37.10.953
In this study, a multibody dynamic model of the cervical spine was developed for a virtual in-vitro cadaveric experiment. The dynamic cervical spine model was reconstructed based on Korean CT images and the material properties of joints and soft tissue obtained from in-vitro experimental literature. The model was validated by comparing the inter-segmental rotation, multi-segmental rotations, load-displacement behavior, ligament force, and facet contact force with the published in-vitro experimental data. The results from the model were similar to published experimental data. The developed dynamic model of the cervical spine can be useful for injury analysis to predict the loads and deformations of the individual soft-tissue elements as well as for virtual in-vitro cadaveric experiments.
Numerical Analysis of Turbulent Flow around Tube Bundle by Applying CFD Best Practice Guideline
Lee, Gong Hee ; Bang, Young Seok ; Woo, Sweng Woong ; Cheng, Ae Ju ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 10, 2013, Pages 961~969
DOI : 10.3795/KSME-B.2013.37.10.961
In this study, the numerical analysis of a turbulent flow around both a staggered and an inline tube bundle was conducted using ANSYS CFX V.13, a commercial CFD software. The flow was assumed to be steady, incompressible, and isothermal. According to the CFD Best Practice Guideline, the sensitivity study for grid size, accuracy of the discretization scheme for convection term, and turbulence model was conducted, and its result was compared with the experimental data to estimate the applicability of the CFD Best Practice Guideline. It was concluded that the CFD Best Practice Guideline did not always guarantee an improvement in the prediction performance of the commercial CFD software in the field of tube bundle flow.