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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korea Society For Power System Engineering
Journal Basic Information
Journal DOI :
The Korea Society for Power System Engineering
Editor in Chief :
Volume & Issues
Volume 14, Issue 6 - Dec 2010
Volume 14, Issue 5 - Oct 2010
Volume 14, Issue 4 - Aug 2010
Volume 14, Issue 3 - Jun 2010
Volume 14, Issue 2 - Apr 2010
Volume 14, Issue 1 - Feb 2010
Selecting the target year
Effect of Frost and Defrost on the Operating Characteristics of Refrigeration System
Kim, J.D. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 5~10
This study was investigated the effect on operating characteristics of apparatus according to frosting and defrosting to develop of new defrosting equipment. The results showed as following. Frost was almost removed using the defrosting equipment with roll brush type that defrosting is possible under operating condition. Also, the temperature of compressor inlet, evaporator inlet and outlet showed higher value because of heat transfer resistance of cooling pipe frost comparing with defrosting condition. And the compressor work showed 10% lower and COP was presented 24% higher values than defrosting condition. Therefore, defrosting for cooling coil of refrigeration and low temperature storage was effected on operation and performance characteristics of equipment. This highly effects on real refrigeration apparatus which is operated in year-around.
Study on Heat Transfer Characteristics of Evaporator with Horizontal Small Diameter Tubes using Natural Refrigerant Propane
Ku, H.K. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 11~16
The evaporation heat transfer characteristics of propane(R-290) in horizontal small diameter tubes were investigated experimentally. The test tubes have inner diameters of 1 mm and 4 mm. Local heat transfer coefficients were measured at heat fluxes of 12,
, mass fluxes of 150,
, and evaporation temperature of
. The experimental results showed that the evaporation heat transfer coefficient of R-290 has an effect on heat flux, mass flux, tube diameter, and vapor quality. The evaporation heat transfer of R-290 has an influenced on nucleate boiling at low quality and convective boiling at high quality. The evaporation heat transfer coefficient of R-290 increases with decreasing inner tube diameter. And the evaporation heat transfer coefficient of R-290 is about 1~3 times higher than that of R-134a.
Analysis of Transient Conduction Heat Loss of Solid Sphere between Constant and Variable Free Convection
Kim, M.J. ; Chea, G.H. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 17~22
A Study on the Thermal Characteristics of the Low Temperature Vacuum Dryer by the Vacuum Chamber Temperature
Choe, S.Y. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 23~28
Of the roughly four million known substances, about 60,000 are processed and sold ; many of these must be dried. Many materials are processed in the liquid state - ideal for mixing and reacting - but most products are needed or wanted as dry, or relatively dry, solids. Usually operation is just below atmospheric pressure, as with direct dryers, but some are built for vacuum operation with pressures as low as 26.66kPa abs.. In spite of the global-class aquiculture agriculture and fisheries technology of our country, the processing technologies are lags behind the other nations relatively. These problems are considered to be caused directly by the lack of drying technologies. This paper is concerned to the experimental results of drying heat transfer characteristics for the green energy type vacuum dryer for the high quality agriculture and fisheries production.
Effect of Vibroacoustic Stimulation to Electroencephalogram
Moon, D.H. ; Choi, M.S. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 29~36
This study was performed with 5 subjects and used three kinds of music and vibroacoustic stimuli wave based upon each kinds of music. Executing music stimulation, vibro tactile and acoustic wave stimulation to human body were performed. Then measured brain waves were analyzed under each condition including before stimulation, stimulation 1, and stimulation 2. Effects by stimulation results could be studied with experiments and summarized results are followings. 1. It may be concluded that effects on brain waves by music and vibroacoustic stimulation might differ under different situations such as stimulation types with vibroacoustic equipment, human body and mental conditions when measuring, etc.. 2. During stimuli by using music A, B, and C, the effect of
wave, and SMR wave power values show same tendency to the subject c but music C had very different tendency during vibroacoustic stimuli. 3. During vibroacoustic stimuli by applying the signals of music C, because SMR wave power value was continually increased with consistency comparing to Bst, this can be estimated that an application of inducing mind concentration condition would be possible under relaxed body and mind conditions. 4. To secure data significance, all measured data need to be tested statistically whether data would be interrelated or not.
A Study on the Effects of the Design Parameters and Sealing Mechanism of the Exhaust Gas in Engine Exhaust System
Choi, B.L. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 37~42
This paper deals with the sealing mechanism of the gasket component and the effects of design parameters for the exhaust manifold. The finite element model includes hot-end exhaust system and a simplified gasket model supplied by ABAQUS software. The mechanical behaviors of bead and body of a gasket are measured after several times of cyclic loads by gasket supplier. From the finite element analysis due to the cyclic thermal loads, the flange of exhaust manifold shows thermal expansion and contraction in longitudinal direction as well as convex and concave deformations with respect to the engine cylinder head. And, the contact pressures of the gasket beads suddenly changes by normal deformation of inlet flanges. Therefore, the magnitudes of contact pressures could be used to determine the sealing characteristics of the exhaust gas in the exhaust system. The distributions of contact pressures in gasket bead lines shows a good agreement with the engine test results.
Study on Optimization of Throttle Margin in High Pressure Turbine of Nuclear Power Plant
Ko, W.S. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 43~49
In the present study, optimization of throttle margin for high pressure turbine to be retrofitted or partially modified for power uprating or life extension in nuclear power plant, has been performed to increase the electrical output. Throttle margin for high pressure turbine is required to maintain all the time the rated power by opening more of governor valves whenever inlet pressure is decreased due to the tube plugging of steam generator. If throttle margin of high pressure turbine is too much compared to remaining lifetime, loss of electrical output due to pressure drop of governor valves is inevitable. On the contrary, if it is too little, the rated power operation can not be accomplished when inlet pressure of high pressure turbine is dropped after many years operation. So, throttle margin for high pressure turbine in nuclear power plant is compromised considering for the degradation of steam generator, governor valve capacity, manufacturing tolerance of high pressure turbine, future plan of power uprating, and remaining lifetime of power plant.
Tribological Wear Behavior of PTFE Impregnated with Cu Nano Particles
Kim, S.Y. ; Kim, E.B. ; Q., Yoo ; Ju, C.S. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 50~55
In order to investigate tribological effects of nano copper particles impregnated(CuN) on surface polytetrafluoroethylene(PTFE) on sealing wear and an experimental study was carried out to determine the wear behavior of copper nano-particles impregnation two kind thickness in super critical
liquid. Experimental results showed that the friction coefficients of CuN PTFE at the low sliding speed(0.44m/s) and the oil temperature (
) were higher than that of virgin PTFE. And a thin nano copper particles impreganated thickness was formed on the surface in the PTFE and the specimen with this treatment has much better friction properties than the original one. Fortunately, at the high load(80 N) and the oil temperature, the friction coefficient of CuN PTFE was lower than that of virgin PTFE. This evidenced the load carrying capacity of CuN PTFE was much better than that of virgin PTFE under the high load condition(80 N) specially. Therefore, it can be concluded that the friction coefficient variation of CuN PTFE is very small but its wear rate decreases greatly with increase in sliding speed.
Weibull Statistical Analysis of Elevated Temperature Tensile Strength and Creep Rupture Time in Stainless Steels
Jung, W.T. ; Kim, Y.S. ; Kim, S.J. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 56~62
This paper is concerned with the stochastic nature of elevated temperature tensile strength and creep rupture time in 18Cr-8Ni stainless steels. The Weibull statistical analysis using the NRIM data sheet has been performed to investigate the effects of variability of the elevated temperature tensile strength and creep rupture time on the testing temperature. From those investigations, the distributions of temperature tensile strength and creep rupture time were well followed in 2-parameter Weibull. The shape parameter and scale parameter for the Weibull distribution of tensile strength were decreased with increasing the testing temperature. For the creep rupture time, generally, the shape parameter were decreased with increasing the testing temperature.
The Study on Eddy Current Characteristic for Surface Defect of Gas Turbine Rotor Material
Ahn, Y.S. ; Gil, D.S. ; Park, S.G. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 63~67
This paper introduces the eddy current signal characteristic of magnetic and non-magnetic gas turbine rotor. In the past, Magnetic particle inspection method was used in magnetic material for qualitative defect evaluation and the ultrasonic test method was used for quantitative evaluation. Nowadays, eddy current method is used in magnetic gas turbine rotor inspection due to advanced sensor design technology. We are studying on the magnetic gas turbine rotor by using eddy current method. We prepared diverse depth specimens made by magnetic and non-magnetic materials. We select optimum frequency according to material standard penetration data and experiment results. We got the signal on magnetic and non-magnetic material about 0.2 mm, 05 mm, 1.0 mm, 1.5 mm 2.0 mm and 2.5 mm depth defects and compare the signal amplitude and signal trend according to defect depth and frequency. The results show that signal amplitudes of magnetic are bigger than non-magnetic material and the trends are similar on every defect depth and frequency. The detection and resolution capabilities of eddy current are more effective in magnetic material than in non-magnetic materials. So, the eddy current method is effective inspection method on magnetic gas turbine rotor. And it has the merits of time saving and simple procedure by elimination of the ultrasonic inspection in traditional inspection method.
Nanoparticle on the Mechanical and Thermal Properties of Epoxy Resin Composites
Moon, Y.J. ; Choi, J.Y. ; Kim, B.A. ; Moon, C.K. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 68~75
The effect of dispersion agent, the content and size of nanoparticle on the mechanical and thermal properties has been investigated in
nanoparticle/epoxy resin composites(nanocomposites). The weight fraction of fabricated nanocomposites were 0, 1, 3, 5%, respectively. The glass transition temperature was lower than pure epoxy resin and decreased with the increasing of nanopaticle content. This is considered that the cross link of epoxy resin during solidification was hindered by the presence of nanoparticles. Nanocomposites of 3wt% content with dispersion agent showed the best tensile strength. The tensile strength of 20㎚
nanocomposites were higher than one of 200nm
A Study on Skew Measurement Technique for the Crane Spreader using a Camera
Kawai, H. ; Kim, Y.B. ; Choi, Y.W. ;
Journal of the Korea Society For Power System Engineering, volume 14, issue 4, 2010, Pages 76~81