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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea Society For Power System Engineering
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Journal DOI :
The Korea Society for Power System Engineering
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Volume & Issues
Volume 9, Issue 4 - Nov 2005
Volume 9, Issue 3 - Aug 2005
Volume 9, Issue 2 - May 2005
Volume 9, Issue 1 - Feb 2005
Selecting the target year
Nondestructive Testing and Applications for Integrity Assessment of Power Plant Facilities by Acoustic Emission Technology - Part 1 : The Theory of Acoustic Emission Technology(I) -
Lee, S.G. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 5~13
Acoustic emission(AE) is defined as the transient elastic waves thar are generated by the rapid release of energy. The advantage of AE is that very early crack growth can be detected well before a highly stressed component may fail. At present, an exact diagnosis is the most reliable means for determining the soundness of structures during power plant operations. AE monitoring has been applied successfully in power plants to determine mechanical problems, pressure vessel integrity and external valves leaks, vacuum leaks, the onset of cavitation in pumps and valves, the presence of flow(or no flow) in piping and heat exchange equipment, etc. Acoustic emission(AE) technology has recently strengthened its application base, and practitioners' understanding of the technique's fundamentals. This paper introduces the methods of a survey and assessment on AE monitoring applications in nuclear, fossil and hydraulic power plant. The main objective of this paper was to obtain information on various applications of AE technology in power plant.
Performance and Emission Characteristics of a Controlled Auto-Ignition Gasoline Engine according to Variation of the Injection Timing
Kim, H.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 14~22
This work deals with a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector is water-cooled by a specially designed coolant passage. Investigated are the engine performance and emission characteristics under the wide range of operating conditions such as 40 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed,
in the inlet-air temperature, and
ATDC in the injection timing. A controlled auto-ignition gasoline engine can be achieved that the ultra lean-burn with self-ignition of gasoline fuel by heating inlet air. It can be achieved that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide had been significantly reduced by CAI combustion compared with conventional spark ignition engine.
Numerical Analysis of Tip Leakage Flows in Axial Flow Turbine Rotors
Chung, H.T. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 23~29
Numerical analysis of three-dimensional viscous flow-fields in the turbine rotor passages was carried out to investigate flow physics including the interaction between secondary vortices, tip leakage vortex, and the rotor wake. The blade tip geometry was accurately modeled adopting the embedded H grid system. An explicit four-stage Runge-Kutta scheme was used for the time integration of both the mean flow and turbulence equations. The computational results for the entire turbine rotor flows, particularly the tip clearance flow and the secondary flows, were interpreted and compared with the experimental data from the Penn State turbine stage. The predictions for major features of the flow field have been found to be in good agreement with the experimental data.
Effect of Number of Rough Walls on Heat Transfer in the Square Channel with a Uniform Heat Flux
Bae, S.T. ; Kim, M.H. ; Lee, D.H. ; Ahn, S.W. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 30~35
Repeated ribs are used on heat exchanger surfaces to promote turbulence and to enhance convective heat transfer. Applications include fuel rods of gas-cooled nuclear reactors, inside cavities of turbine blades, and internal surfaces pipes used in heat exchangers. Despite the great number of literature papers, only few experimental data concerns detailed distributions of friction factors and heat transfer coefficients in square channels varying the number of rough walls. This issue was tackled by investigating effects of different number of ribbed walls on heat transfer and friction characteristics in square channel. The rough wall had a
inclined square rib. Uniform heat flux was maintained on the whole inner heat transfer channel area. The heat transfer coefficient and friction factor values increased with increasing the number of rough walls.
Numerical Analysis of A Vortex Cyclone in A Recirculating Aquaculture System
Jeong, S.K. ; Kim, E. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 36~41
This study investigated the performance of a vortex hydrocyclone for solid removal in a recirculating aquaculture system. In a fish-breeding industry, effluent water is mainly disposed by gravity sedimentation. Thus, a large settling tank and a lot of water are needed to purify effluent water. However, this typical method does not show consistent efficiency. In case of low efficiency, discharged water contains a lot of feeding sediments. This causes environmental problems. Instead of this typical method a hydrocylone is tested to discharge water which contains a lot of feeding sediments. In this paper, a hydrocyclone with low velocity and pressure drop in a recirculating aquaculture system is investigated.
Vibration Analysis of a Rectangular Plate with Stiffeners Using the Transfer Stiffness Coefficient Method
Moon, D.H. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 42~49
The vibration analysis of a rectangular plate with stiffeners is formulated by using the transfer stiffness coefficient method (TSCM). This method is based on the concept of the successive transmission of stiffness coefficients which are defined as the relationship between the force vector and the displacement vector at an arbitrary nodal line. In order to confirm the validity of the present method, bending vibration analysis for a rectangular plate with stiffener is carried out on a personal computer by using the present method and the finite element method (FEM). Through comparing computational results of the TSCM and the FEM, the effectivness of the TSCM from the viewpoint of computational cost, that is, computational time and storage is demonstrated.
Effects of Torsional Stress on the Corrosion Characteristics in the Rotor Assembly of Marine Diesel Engine Supercharger
Jo, S.K. ; Kong, Y.S. ; Kim, Y.D. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 50~56
The corrosion experiment was performed for 120 hours on the specimens in the natural seawater tank with four steps of the loaded torsional stress. The surface corrosion pattern of SCM440 area was showed global corrosion and narrow pitting, that was cause by galvanic corrosion between friction welded IN713LC and SCM440. But corrosion does not proceeded from IN713LC area. Initially, the average relative electrode potential and corrosion current were decreased suddenly, by and large, it was stabilized gradually tend to decreasing with the elapse of the immersion time. The corrosion rate was decreased by increasing the load stress, but 200 MPa specimen was showed most large value.
Root Cause Analysis on Delamination Failure between Coating Film and Paper
Lee, D.B. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 57~63
In the calendar and the advertising catalog, the surface is usually coated by coating polypropylene film. The delamination failure of coating film depends on surface roughness and quality of the substrate paper. In this paper, the mechanisms of delamination failure between the coating film and the paper is investigated by using the root cause analysis as one of techniques of reliability evaluation. The papers used in failure analysis are three kind products made by two domestic and one foreign companies. It found that the main causes of delamination failure between the coating film and the paper were the creation of microvoids caused by shape of filler and their growth caused by contraction of paper.
Acceleration Test of Ion Migration for PCB Electronic Reliability Evaluation
Lee, D.B. ; Kim, J.H. ; Kang, S.K. ; Chang, S.W. ; Lim, J.H. ; Ryu, D.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 64~69
In evaluation of electronic reliability on the PCB(Print Circuit Borad),electrochemical migration is one of main test objects. The phenomenon of electrochemical migration occurs in the environment of the hight humidity and the hight temperature under bias through a continuous aqueous electrolyte. In this paper, the generating mechanism of electrochemical migration is investigated by using water drop acceleration test under various waters. The waters used in the water drop test are city water, distilled water and ionic water. It found that the generated velocity of electrochemical migration depended on electrolyte quantity which included in the various waters.
The Effect of Alloy Elements on the Damping Capacity and Plasma Ion Nitriding Characteristic of Fe-Cr-Mn-X Alloys [I Damping Capacity]
Son, D.U. ; Jeong, S.H. ; Kim, J.H. ; Lee, J.M. ; Kim, I.S. ; Kang, C.Y. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 70~75
The damping property of Fe-12Cr-22Mn-X alloys has been investigated to develop high damping and high strength alloy. Particularly, the effect of the phase of austenite, alpha and epsilon martensite, which constitute the structure of the alloys Fe-12Cr-22Mn-X alloys, on the damping capacity at room temperature has been investigated. Various fraction of these phases were formed depending on the alloy element and cold work degree. The damping capacity is strongly affected by
martensite while the other phase, such as
martensite, actually exhibit little effect on damping capacity. In case of Fe-12Cr-22Mn-3Co alloy, the large volume fraction of
martensite formed at about 30% cold rolling, and in case of Fe-12Cr-22Mn-1Ti alloy, formed at about 20% cold rolling and showed the highest damping capacity. Damping capacity showed higher value in Fe-12Cr-22Mn-1Ti alloy than one in Fe-12Cr-22Mn-3Co alloy.
The Effect of Alloy Elements on the Damping Capacity and Plasma Ion Nitriding Characteristic of Fe-Cr-Mn-X Alloys. [II Plasma Ion Nitriding Characteristic]
Son, D.U. ; Lee, H.H. ; Seong, J.H. ; Park, K.S. ; Kim, C.K. ; Kang, C.Y. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 76~81
The effect of micro-pulse plasma nitriding temperature and time on the case thickness, hardness and nitride formation in the surface of Fe-12Cr-22Mn-X alloy with 3% Co and 1% Ti alloys elements investigated. External compound layer and internal diffusion layer was constituted in plasma nitride case of Fe-12Cr-22Mn-X alloys and formed nitride phase such as
. Case depth increased with increasing the plasma nitriding temperature and time. Surface hardness of nitrided Fe-12Cr-22Mn-X alloys obtained the above value of Hv 1,600 and case depth obtained the above value of
in Fe-12Cr-22Mn-3Co alloy and
in Fe-12Cr-22Mn-1Ti alloy. Wear-resistance increased with increasing plasma nitriding time and showing the higher value in Fe-12Cr-22Mn-1Ti alloy than Fe-12Cr-22Mn-3Co alloy.
Dynamic Analysis of Evaporator for Optimum Control in Refrigeration System
Jeong, S.K. ; Hua, Li ; Choi, K.H. ; Yoon, J.I. ; Kim, E.P. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 1, 2005, Pages 82~88
This paper presents numerical study on dynamic characteristics of evaporator to control evaporator superheat and compressor capacity with optimum condition in refrigeration system. It is very important to reduce energy consumption and to keep room temperature within a very restricted range with minimum oscillation in some special applications of the refrigeration system. Heat exchange is mainly happened in the evaporator. So, making mathematical model of evaporator and analyzing evaporator characteristics are necessary in order to control the superheat and the capacity of the system. A mathematical model based on the one dimensional partial differential equations representing mass and energy conservation and a tube-wall energy is described. A set of ordinary differential equation is formulated by integrating separately over the two regions(two-phase and vapor) generally presented in a heat exchanger.