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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 30, Issue 12 - Dec 2006
Volume 30, Issue 11 - Nov 2006
Volume 30, Issue 10 - Oct 2006
Volume 30, Issue 9 - Sep 2006
Volume 30, Issue 8 - Aug 2006
Volume 30, Issue 7 - Jul 2006
Volume 30, Issue 6 - Jun 2006
Volume 30, Issue 5 - May 2006
Volume 30, Issue 4 - Apr 2006
Volume 30, Issue 3 - Mar 2006
Volume 30, Issue 2 - Feb 2006
Volume 30, Issue 1 - Jan 2006
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Part-load Performance Characteristics of a Solid Oxide Fuel Cell/Gas Turbine Hybrid Power System Operating with Various Load-following Operation Modes
Kim Jae-Hoon ; Yang Jin-Sik ; Ro Sung-Tack ; Sohn Jeong-Lak ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 193~200
DOI : 10.3795/KSME-B.2006.30.3.193
The purpose of this study is to compare the part-load performance of a SOFC/GT hybrid power system with three different kinds of load-following operation modes. The primary mode for the part load operation of a hybrid power system is the reduction of supplied fuel (e.g., fuel control mode) to the hybrid system. The other two options, i.e., variable speed and VIGV controls, are related to the reduction of supplied air simultaneously with the reduction of supplied fuel to the system. With the performance analysis of a SOFC/GT hybrid power system, it is concluded that the variable speed con佐ol mode Provides the best performance for the part-load operations. It is also found that the VIGV control mode, with its better performance behavior than the fuel control mode, can be used as an important option for the part-load operation especially in case that the variable speed control mode can not be adopted.
1- Dimensional Transient Radiative Heat Transfer Using Finite Volume Method with 2-Order Upwind Scheme and QUICK Scheme
Lee Gun-Ho ; Kim Man-Young ; Byun Do-Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 201~207
DOI : 10.3795/KSME-B.2006.30.3.201
Transient radiative heat transfer is analyzed in a one-dimensional slab using finite volume method (FVM). In this study, the step,
order upwind, and QUICK schemes are used for incident diffuse radiation and collimated beam, respectively. The results fer diffuse radiation show that all schemes applied in this study give good agreements with available published results. In case of collimated beam however, the results show deviations from the analytical solutions. To successfully describe the propagations of collimated beam shock capturing schemes such as TVD scheme are need to be developed.
A Study on Performance and Simultaneous Reduction of Smoke and NOx Emission by an DMM Addition and Application of EGR Method in a Diesel Engine
Oh Young-Taig ; Choi Seung-Hun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 208~214
DOI : 10.3795/KSME-B.2006.30.3.208
, also known as methylal or DMM, is an oxygenated additive that contains 42.5% oxygen by weight and is soluble in diesel fuel. It is a colorless liquid and a gas-to-liquid chemical 방tat has been evaluated for use as a diesel fuel component. Experiments were conducted by using the five blends with different volumetric percentage of DMM(2.5, 5, 7.5, 10, and 12.5%) in baseline diesel fuel. The test engine was single cylinder, four stroke, DI diesel engine unmodified. Also, data was collected for steady state operation at 24 engine speed-load conditions. The focus of this study was to investigate the effects of the addition of oxygenated fuel to diesel fuel on the engine-out emissions and the performance. Smoke emissions of all DMM blends were reduced substantially in comparison with conventional diesel fuel. These results indicate that DMM may be an effective blendstock for diesel fuel as an environment-friendly alternative fuel. Besides, this study showed that simultaneous reduction of smoke and NOx emissions could be achieved by oxygenated fuel and EGR method that was applied to decrease NOx emissions increasing with smoke emissions reduction.
Development of Stereoscopic PTV Technique and Performance Tests
Lee Sang-Joon ; Yoon Jong-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 215~221
DOI : 10.3795/KSME-B.2006.30.3.215
A stereoscopic particle tracking velocimetry (SPTV) technique based on the 2-frame hybrid particle tracking velocimetry (PTV) method was developed. The expansion of 2D PTV to SPTV is facilitated by the fact that the PTV method tracks individual particle centroids. To evaluate the performance and measurement accuracy of the present SPTV technique, it was applied to flow images of rigid body translation and synthetic standard images of jet shear flow and impinging jet flow. The data processing routine and measurement uncertainty of the SPTV technique are compared with those of conventional stereoscopic particle image velecimet.y (SPBV). In addition, the centroid translation effect of 2D particle image velocimetry (PIV) is defined and its effect on SPIV measurements is discussed. Compared to the SPIV method, the SPTV technique has inherited merits of concise and precise velocity evaluation procedures and provides better spatial resolution and measurement accuracy.
Numerical Study on the Three-Dimensional Centrifugal Compressor Volute Flow
Yoon Ju-Sig ; Park Ki-Cheol ; Chang Keun-Shik ; Bae Hwang ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 222~229
DOI : 10.3795/KSME-B.2006.30.3.222
Three dimensional turbulent flow in the scroll volute of centrifugal compressor has been numerically investigated in this paper by solving the Navier-Stokes equations and
equation model. The computational grid for the flow field of the scroll volute has been constructed based on the multi-block grid concept, which is good to avoid the central grid singularity as well as to promote grid stretching toward the volute wall. Numerical result has been obtained for both the two- and three- dimensions. For the latter flow, result of the scroll volute flow is compared with that of the straight conical volute. This comparison has sorted out the characteristic features of the three-dimensional scroll-type volute flow of centrifugal compressor.
Numerical Study on the Variation of Axial Thrust of Rotating Disc with Pump-Out Vane
Seong Seong-Mo ; Kang Shin-Hyoung ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 230~237
DOI : 10.3795/KSME-B.2006.30.3.230
Flows in the cavity with pump out vane are calculated using the CFX-Tascflow CFD code. flow calculations are performed for different values of vane height, numbers, leakage flow rate, and rotational speed. The flow is very complex and three dimensional with strong vortex and leakage flow over the vane. The variations of pressure coefficient and K-factor with these parameters and resulting effects on the thrust and torque are studied. The present study contributes to showing the capability of flow simulation of back cavity with pump-out vane. The calculated results are good enough to be used back cavity design.
Conjugate Heat Transfer of Laminar Film Condensation Along a Horizontal Plate
Lee Euk-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 238~245
DOI : 10.3795/KSME-B.2006.30.3.238
This paper proposes appropriate conjugate parameters and dimensionless temperatures to analysis the conjugate problem of heat conduction in solid wall coupled with laminar film condensation flow adjacent to horizontal flat plate. An efficient methods for some fluids are proposed for its solution. The momentum and energy balance equations are reduced to a nonlinear system of ordinary differential equations with four parameters: the Prandtl number, Pr, Modified Jacob number,
, defined by an overall temperature difference, a property ratio
and the conjugate parameter
. The obtained similarity solution reveals the effect of the conjugate parameter, and the results are compared with the simplified solution. The variations of the heat transfer rates as well as the interface temperature and frictions along the plate are shown explicitly.
Cooling System with Nanofluidic Loop Thermosyphon
Park Jong-Chan ; Lim Taek-Kyu ; Lee Chung-Gu ; Shin Dong-Ryun ; Park Gi-Ho ; Rhi Seok-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 246~254
DOI : 10.3795/KSME-B.2006.30.3.246
The present study shows the experimental and modeling results of the cooling system using nanofludic loop thermosyphon. the experimental results show that nanofluid is not effective for small scale cooling system. The heat transfer performance is not much improved with the current small scale loop system comparing with the convectional water based loop system. In this study, various effects of nanofluids such as the concentration, the md of particle, host fluid, and heat capacity and so on were investigated. With nanofluid as the working fluid, the flow instability was improved at a certain concentration.
Experimental Study on Flow Characteristics in a Micro-stenosis Inside a Microchannel
Ji Ho-Seong ; Lee Sang-Joon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 255~261
DOI : 10.3795/KSME-B.2006.30.3.255
Flow characteristics of DI water in a microchannel with a stenosis were investigated using .a micro PIV system with varying flow rate. The width and depth of the PDMS micro-channel were
, respectively. To Investigate flow characteristics in the micro-stenosis, the same experiment was carried out in a straight microchannel under the same flow rate. The measured mean velocity fields were almost symmetric with respect to the channel centerline. The experimental results are well agreed with the theoretical Hagen-Poiseuille profile. In the contraction part of the micro-stenosis, the oncoming flow is accelerated rapidly and the maximum velocity occurs at the throat, almost 4.99 time faster than that without the stenosis.
Study on the Segregation Algorithms of the Incompressible Navier-Stokes Equations Using P1P1/P2P1 Finite Element Formulation
Choi Hyoung-G. ; Yoo Jung-Y. ; Park Jae-I. ; Cho Myung-H. ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 262~269
DOI : 10.3795/KSME-B.2006.30.3.262
Segregation algorithms of the incompressible Wavier-Stokes equations using P1P1/P2P1 finite element formulation are newly proposed. P1P1 formulation allocates velocity and pressure at the same nodes, while P2P1 formulation allocates pressure only at the vertex nodes and velocity at both the vertex and the midpoint nodes. For a comparison of both the elapsed time and the accuracy between the two methods, they have been applied to the well-known benchmark problems. The three cases chosen are the two-dimensional steady and unsteady flows around a fixed cylinder, decaying vortex, and impinging slot jet. It is shown that the proposed P2P1 semi-segregation algorithm performs better than the conventional P1P1 segregation algorithm in terms of both accuracy and computation time.
Inverse Boundary Temperature Estimation in a Two-Dimensional Cylindrical Enclosure Using Automatic Differentiation and Broyden Combined Method
Kim Ki-Wan ; Kim Dong-Min ; Baek Seung-Wook ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 270~277
DOI : 10.3795/KSME-B.2006.30.3.270
Inverse radiation problems were solved for estimating boundary temperature distribution in a way of function estimation approach in an axisymmetric absorbing, emitting and scattering medium, given the measured radiative data. In order to reduce the computational time fur the calculation of sensitivity matrix, automatic differentiation and Broyden combined method were adopted, and their computational precision and efficiency were compared with the result obtained by finite difference approximation.. In inverse analysis, the effects of the precision of sensitivity matrix, the number of measurement points and measurement error on the estimation accuracy had been inspected using quasi-Newton method as an inverse method. Inverse solutions were validated with the result acquired by additional inverse methods of conjugate-gradient method or Levenberg-Marquardt method.
Structure Design and Experimental Appraisal of the Drag Force Type Vertical Axis Wind Turbine
Kim Dong-Keon ; Keum Jong-Yoon ; Yoon Soon-Hyun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 30, issue 3, 2006, Pages 278~286
DOI : 10.3795/KSME-B.2006.30.3.278
Experiments were conducted to estimate the performance of drag force type vertical axis wind turbine with an opening-shutting rotor. It was operated by the difference in drag force generated on both sides of the blades. The rotational speed was measured by a tachometer in a wind tunnel and the tunnel wind speed was measured by using a pilot-static tube and a micro manometer. The performance test for a prototype was accomplished by calculating power, power coefficient, torque coefficient from the measurement of torque and rpm by a dynamometer controller. Various design parameters, such as the number of blades(B), blade aspect ratio(W/R), angle of blades
and drag coefficient acting on a blade, were considered for optimal conditions. At the experiment of miniature model, maximum efficiency was found at N=15,
and W/R=0.32. The measured test variables were power, torque, rotational speed, and wind speeds. The data presented are in the form of power and torque coefficients as a function of tip-speed ratio V/U. Maximum power was found in case of
, when the power and torque coefficient were 0.14 and 0.37 respectively. Comparing model test with prototype test, similarity law by advance ratio for vertical axis wind turbine was confirmed.