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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
Journal Basic Information
Journal DOI :
The Korea Society for Power System Engineering
Editor in Chief :
Volume & Issues
Volume 18, Issue 6 - Dec 2014
Volume 18, Issue 5 - Oct 2014
Volume 18, Issue 4 - Aug 2014
Volume 18, Issue 3 - Jun 2014
Volume 18, Issue 2 - Apr 2014
Volume 18, Issue 1 - Feb 2014
Selecting the target year
Fabrication of Graphene Using Exfoliation Method
Lee, Jeong-Su ; Kim, Bu-Ahn ; Moon, Chang-Kwon ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 7~12
DOI : 10.9726/kspse.2014.18.6.007
The effect of various synthesis conditions in the fabrication of graphene using the exfoliation methods has been investigated. Graphite oxide and graphene fabricated by various synthesis conditions were identified by SEM and XRD. Graphite oxide was made from graphite by the chemical oxidation, and graphene was manufactured from graphite oxide by thermal exfoliation method. As a result, it is confirmed that graphite oxide was well formed from graphite, and the graphene could be obtained from graphite oxide. And it was found that the interlayer spacing between the graphene layers depended on the reaction time and particle size, regardless of the reaction temperature from
Evaluation of the Turbulence Models on the Aerodynamic Performance of Three-Dimensional Small-Size Axial Fan
Kim, Jang-Kweon ; Oh, Seok-Hyung ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 13~20
DOI : 10.9726/kspse.2014.18.6.013
The steady-state, incompressible and three-dimensional numerical analysis was carried out to evaluate turbulent models on the aerodynamic performance of a small-size axial fan(SSAF). The prediction performance on the static pressure of all turbulent models is going downhill at the high static pressure and low flowrate region, but has improved at the axial flow region. In consequence, all turbulent models predict the static pressure coefficient with an error performance less than about 4% after the region of the flowrate coefficient of about 0.14. Especially, the turbulent model of SST
shows the best prediction performance equivalent to an error performance less than about 2% on the static pressure.
A Study on the Spray Characteristics of CRDI System with Ambient Pressure
Kim, Sang-Am ; Wang, Woo-Gyeong ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 21~28
DOI : 10.9726/kspse.2014.18.6.021
The studies of the spray characteristics for a CRDI engine had been advancing by many researchers, because the performance and exhaust emission were significantly affected with the spray characteristics. But most experiments of the studies would be done at low ambient pressure conditions under 2MPa. In this study, injection rates were measured with Zeuch`s method at various ambient pressures to 5MPa and a constant injection pressure of 130MPa. On the same conditions, non-evaporating spray images were taken with a high speed camera and analyzed carefully with Adobe Photoshop CS3. Macroscopic spray characteristics and breakup processes in the spray could be found from the examined and analyzed data. The initial injection rate, penetration, angle, velocity and breakup of the spray were practically affected with a variation of the ambient pressure, but the injection start time and injection period were scarcely affected. As the ambient pressure was higher, the breakup of a high density droplet region in the spray was happened slowly and the main position of breakup was shifted from a front of the spray to a upstream around a nozzle. The results and techniques of spray visualization and injection rate measurement in this study would be practically effective to study a high pressure diesel spray for a CRDI.
A Study on the Electrochemical Characteristics of Al-Si Casting Alloys in NaCl Solution
Woo, Sang-Hyun ; Son, Young-Jin ; Lee, Byung-Woo ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 29~33
DOI : 10.9726/kspse.2014.18.6.029
The electrochemical characteristics of Al-Si casting alloys (Al-10%Si, Al-9%Si, Al-7%Si) in 3.5% NaCl solution at room temperature was studied using potentiodynamic techniques. The electrochemical values of corrosion potential(
), corrosion current density(
) and corrosion rate(mpy) were examined. The Al-Si alloys had several compounds such as
which could affect corrosion resistance significantly. The potentiodynamic polarization curve exhibited typical active behavior in anodic polarization curve. The major corrosion mechansim for the Al-Si alloys were pitting and grain boundary corrosion. As increasing Si and Cu contents, their corrosion resistance was decreased.
Finite Element Analysis for the Behavior of the Casing of a Pulverizer Mill Planetary Gear Reducer
Seo, Ji-Hwan ; Kim, Seon-Jin ; Jung, Min-Hwa ; Kim, Byung-Tak ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 34~39
DOI : 10.9726/kspse.2014.18.6.034
In this study, the structural analysis and the modal analysis are conducted to investigate the stress level, the deformation characteristics and the natural modes of the casing of a planetary gear reducer for a 800kW grade pulverizer mill. The casing is subjected to the load, 2800 kN, from the lump coals in the pulverizing process. Because of the symmetry, the half portion of the reducer casing is modeled for the stress analysis. But the full model is used to find out the eigenvalues and natural modes for the modal analysis. The contact conditions are applied between the thrust pad bearing and the adjacent contacting parts. The results shows that the casing structure has the sufficient strength and stiffness to support the load under consideration. ANSYS version 15 is employed to perform the numerical study.
Anti-Corrosion Characteristics of WC-based Alloy Coatings Fabricated by HVOF Process - Polarization Characteristics in Alkaline Solution -
Kim, Tae-Yong ; Kim, Yeong-Sik ; Kim, Jae-Dong ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 40~44
DOI : 10.9726/kspse.2014.18.6.040
The purpose of this paper is to investigate polarization characteristics of WC-based alloy coatings in alkaline solution. The coatings were fabricated with WC-CrC-Ni, WC-Co-Cr and WC-Co composite powders by HVOF process. Corrosion tests of coatings and substrate were carried out using potentiostat/galvanostat at solution with pH 8 and pH 13. Corrosion potential(Ecorr) and corrosion current density(Icorr) could be studied from polarization curve, and corrosion behavior was analyzed by SEM and EDS. WC-Co-Cr coating and WC-CrC-Ni coating showed more favorable anti-corrosion characteristics than WC-Co coating and substrate at solution with pH 8 and pH 13.
Vibration Transfer Characteristic of Seat with the Auxiliary Plastic Member for Movie Theater Chair
Kang, Hwa-Joong ; Kim, Tae-Gyun ; Moon, Deok-Hong ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 45~50
DOI : 10.9726/kspse.2014.18.6.045
In the previous paper, we have reported on the development of foaming sponge seat with the auxiliary spring member and suggested new possibility of the special seat with the auxiliary plastic member for movie theater chair. In this study, we have examined the major design parameters needed in the development of a foaming sponge seat in which the mesh type plastic member are inserted to improve the vibration transfer effect of a chair seat. Through analyzing several prototypes by applying experimentation as well as the experimental modal analysis method, it was confirmed that the effect of vibration transfer can be improved through the use of a mesh type plastic member and applied to the design of practical chair seat.
A Study on the Performance Characteristics of Low Pressure Hydraulic Circuit of Common Rail System
Lee, Choon-Tae ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 51~57
DOI : 10.9726/kspse.2014.18.6.051
High pressure common rail injection technology has revolutionized the diesel industry. Over the last decade it has allowed engine builders to run higher injection pressures as much as above 1,300bar in order to increase engine efficiency, while reducing emissions. This common rail system has low pressure circuit which is consist of low pressure pump, cascade overflow valve and flow metering unit. The low pressure pump`s purpose is to feed fuel oil to the high pressure pump. The cascade overflow valve keeps pressure in front of the metering unit constant and provides lubrication for the high pressure pump. The metering unit, known as the MPROP or fuel pressure regulator, regulates the maximum flow rate delivers to the rail. In this paper, we have investigated the performance characteristics of each components and total low pressure circuit of common rail system.
Effects of Counterpart Materials on Wear Behavior of Thermally Sprayed STS316 Coatings
Lee, Jae-Hong ; Kim, Yeong-Sik ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 58~63
DOI : 10.9726/kspse.2014.18.6.058
This paper deals with the effects of counterpart materials on the wear behavior of thermally sprayed STS316 coatings. STS316 powders were flame-sprayed onto a carbon steel substrate. Dry sliding wear tests were performed using the applied loads of 15 N. AISI52100,
balls were used as counterpart materials. Wear behavior of STS316 coatings against different counterpart materials were studied using a scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that the wear behavior of thermally sprayed STS316 coatings strongly depends on the type of counterpart material. Dominant wear mechanism was similar for all studied materials as failure of adhesion film except for Si3N4 used as counterpart material. In the case of Si3N4 used as counterpart material, dominant wear mechanism was abrasion.
Static Analysis of Axisymmetric Circular Plates under Lateral Loading Using Transfer of Stiffness Coefficient
Choi, Myung-Soo ; Yeo, Dong-Jun ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 64~69
DOI : 10.9726/kspse.2014.18.6.064
A circular plate is one of the important structures in many industrial fields. In static analysis of a circular plate, we may obtain an exact solution by analytical method, but it is limited to a simple circular plate. Thus, many researchers and designers have used numerical methods such as the finite element method. The authors of this paper developed the finite element-transfer stiffness coefficient method (FE-TSCM) for static and dynamic analyses of various structures. FE-TSCM is the combination of the modeling technique of the finite element method (FEM) and the transfer technique of the transfer stiffness coefficient method (TSCM). FE-TSCM has the advantages of both FEM and FE-TSCM. In this paper, the authors formulate the computational algorithm for the static analysis of axisymmetric circular plates under lateral loading using FE-TSCM. The computational results for three computational models obtained by FE-TSCM are compared with those obtained by FEM in order to confirm the accuracy of FE-TSCM.
The Study on the Assesment Fuel Economy of Hybrid Vehicle on Test Modes
Kim, Ki-Ho ; Kim, Sung-Woo ; Lee, Min-Ho ; Oh, Sang-Gi ; Lee, Seung-Ho ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 70~76
DOI : 10.9726/kspse.2014.18.6.070
Surely fuel economy(F.E.) label is needed to meet consumer`s right to know. Korea has developed and adopted F.E. correction equation similar to the feeling, because consumer complain about F.E. label higher than they feel. Recently, through continuous research and development high-efficiency & performance green car like HEV, PHEV and EV are being sold. In this situation, it is needed to know whether the current equation can reflect a part of their improved technic or not. In this paper, to review current equation through test using hybrid vehicles on 5-cycle SOC, correction equation and F.E were discussed. The result show HEV didn`t meet the SOC error standard on US06. Also, HEV has bigger F.E. difference between FTP-75 and 5-cycle than conventional vehicles. However, the correction equation that include HEV almost same with current one.
The Study on the Assesment Greenhouse Gases and Air Pollutants of Diesel Vehicle according to Ambient Temperature and Driving Condition
Kim, Ki-Ho ; Kim, Sung-Woo ; Lee, Min-Ho ; Oh, Sang-Gi ; Lee, Seung-Ho ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 77~83
DOI : 10.9726/kspse.2014.18.6.077
As the interest on the air pollution is gradually risen up at home and abroad, their vehicle emission regulations have been reinforcing by steps. PM regulation was also reinforced 4times for the last 13years and has been applied to SI vehicles after EURO 5. Additionally, knowing that small particles of PM can easily penetrate deep into lungs PM number was added on the regulation from EURO5+ and is applied to CI vehicles. Also, PN regulation is going to be applied to SI vehicles. But, because the regulation is appled to only a general test mode of each countries that is performed at
, it is unclear whether the regulation can work on the other ambient temperature conditions or not. In this paper, to know that exhaust emission characteristics at the special conditions CI vehicles(CRDi w, w/o DPF) were tested using 5-cycle mode, NEDC mode at 5-ambient temperatures (35, 25, 0, -7 and -15) and the exhaust emission test results were discussed. The results show that the vehicle with DPF emits much low PM(and PM number) on all of the test mode. However, NOx of the other mode was emitted higher than regulation mode. Also. NOx was sharply increased according to decreasing Ambient Temperature.
Degradation of 2,3-dichlorophenol by a Photo-Fenton Process with Continuous Pump-Feeding of Hydrogen Peroxide
Kim, Il-Kyu ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 84~90
DOI : 10.9726/kspse.2014.18.6.084
The degradation of 2,3-dichlorophenol(2,3-diCP) by various advanced oxidation systems with continuous feeding of hydrogen peroxide including the ultraviolet/hydrogen peroxide, the Fenton and the photo-Fenton process has been conducted. The highest removal efficiency for 2,3-diCP in the aqueous phase was obtained by the photo-Fenton process among the advanced oxidation systems. In the photo-Fenton process, The removal efficiency of 2,3-diCP decreased with increasing pH in the range of 3 to 6, and it decreased with increasing initial concentration. As the intermediates of 2,3-diCP by photo-fenton reaction, 3,4-chlorocatechol and 2,3-dichlorohydroquinone were detected, thus the degradation pathways were proposed.
Research on Die Machining using 3D Printing and CAM System
Han, Kyu-Taek ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 91~98
DOI : 10.9726/kspse.2014.18.6.091
The purpose of this research is to investigate optimum machining conditions to improve the quality of die using the CAD/CAM system(Power Shape/Power Mill) and 3D printing. Surface roughness is widely used as an index for processing degree of accuracy. The Power Shape was used to model the shape of product. And the model shape is confirmed by 3D printing system(BFB-3000). Also, tool path and NC-codes were generated using Power Mill. Finally, the product was cut using CNC machine(NBS-2025). The cutting time and surface roughness were measured by measuring instrument. And then this process was repeated by changing the conditions to find optimal machining conditions. The surface roughness behavior with regard to specific factors were analyzed. Through this study, the optimal machining condition can be obtained.
A Comparison of Operating Characteristics for Industrial Water Cooler with Variation of Control Methods
Baek, Seung-Moon ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 99~105
DOI : 10.9726/kspse.2014.18.6.099
This paper presents a comparison of operating characteristics for industrial water cooler with variation control methods. The performance analysis regarding the characteristics of condensation capacity, evaporation capacity, compressor load, COP of an on-off type cooler, a hot gas-bypass control type cooler and an inverter control type cooler with respect to the system load is reviewed, respectively. The primary results are as following: the variation of required compressor load of an on-off type cooler with respect to load is 5%, that of hot gas-bypass type is 18% and 66% for an inverter control type cooler. As the result shows, an inverter control type yields relatively huge difference of required compressor load compared to other types of control system. In terms of partial load, COP of an inverter control type cooler presents the highest value, and is considered as the optimized type for the used of the system involving frequent partial load.
Effect of Fuel Injection Timing on Nitrous Oxide Emission from Diesel Engine
Yoo, Dong-Hoon ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 106~112
DOI : 10.9726/kspse.2014.18.6.106
The diesel engine, which has high compression ratio than other heat engines, has been using as the main power source of marine transport. Especially, since marine diesel engines offer better specific fuel consumption (SFC), it is environment-friendly compared to those used in other industries. However, attentio should be focused on emissions such as nitrous oxide (
) which is generated from combustion of low-grade fuels. Because
in the atmosphere is very stable, the global warming potential (GWP) of
is 310 times as large as that of
, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. It has been hitherto noted on the
exhaust characteristics from stationary power plants and land transportations, but reports on
emission from the marine diesel engine are very limited. In this experimental study, a author investigated
emission characteristics by using changed diesel fuel components of nitrogen and sulfur concentration, assessed on the factors which affect
generation in combustion. The experimental results showed that
emission exhibited increasement with increasing of sulfur concentration in fuel. However, all kinds of nitrogen component additives used in experiment could not change
Examination on Combustion Quality Analysis of Residue Heavy Fuel Oil and Improvement of Combustion Quality Using Pre-injection
Yoo, Dong-Hoon ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 113~119
DOI : 10.9726/kspse.2014.18.6.113
Due to the development of the petroleum refining technology and continuously increased demand from markets, a quantity of gasoline and diesel oil produced from a restricted quantity of crude oil has been increasing, and residual fuel to be used at marine diesel engines has been gradually becoming low quality. As a result, it was recently reported that trouble oils which cause abnormal combustion such as knocking with extreme noise and misfire from internal combustion engines were increasing throughout the world. In this study, an author investigated ignitability and combustion quality by using combustion analyzer with constant volume(FCA, Fuel Combustion Analyzer) and middle speed diesel engine about MDO(Marine Diesel Oil), HFO(Heavy Fuel Oil), LCO(Light Cycle Oil) and Blend-HFO which was blended LCO of 1000 liters with HFO of 600 liters. Moreover, for betterment of ignitability and combustion quality of injected fuels, multi-injection experiment was carried out in the diesel engine using Blend-HFO. According to the results of FCA analysis, ignitability and combustion quality was bad in the order of MDO
Performance Analysis of 1MW Organic Rankine Cycle with Liquid-Vapor Ejector using Effluent from Power Plant
Kim, Hyeon-Uk ; Yoon, Jung-In ; Son, Chang-Hyo ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 120~125
DOI : 10.9726/kspse.2014.18.6.120
In this paper, suitable working fluid of 1MW Organic Rankine Cycle(ORC) with liquid-vapor ejector using effluent from power plant is selected. The results of comparison performance of 5 refrigerants are as follows; R600a, R134a, R1270, R236fa, R235fa. The operating parameters considered in this study include the condensation capacity evaporation capacity and efficiency. As a result of comparison of basic ORC system and with liquid-vapor ejector, with ORC system presents the higher system efficiency since the ejector makes the turbine outlet pressure lower than condensation pressure through its pressure recovery. Also, this ejector ORC system is advantageous in miniaturizing the size of components owing to decrease of evaporation capacity and condensation capacity.
A Study on the Additives of mixed Gas charged in Thermostatic Bulb for Expansion Valve
Kim, Si-Young ; Ju, Chang-Sik ; Koo, Su-Jin ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 126~132
DOI : 10.9726/kspse.2014.18.6.126
The P-T characteristics of mixed refrigerant in thermostatic expansion valve sensing bulb were studied using R-134a and R-410A refrigerant. The characteristics of mixed refrigerant were investigated according to pressure variation and the variation of composition ratio of R-134A and R-410A in the temperature range of
. The Thermodynamic characteristic values of the mixed refrigerants were identified using the characteristic value analysis program of mixed refrigerant(Refrop v9.0, NIST). The P-T characteristics in the case of the mixing ratio of 90:10 for R-410A and R-134A were the same result as R-22. And the physical properties showed similar results with R-22. The Maximum operating pressure(MOP) of mixed refrigerant showed a tendency to decrease with decreasing the mixing ratio of additive gases(
or He) gases. The characteristics in the case of the mixing ratio of 80:1 for mixed refrigerant and additive gases were the similar result as Reference refrigerant.(R-22 MOP, Sporlan company) In addition
and He, both showed the same results. It was able to confirm that a MOP on the thermostatic expansion valve sensing bulb can be maintained by adjusting the mixing ratio of mixed refrigerant gases and additive gases.
Degradation of a Refractory Organic Contaminant by Photocatalytic Systems
Kim, Il-Kyu ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 133~139
DOI : 10.9726/kspse.2014.18.6.133
In this research, the photocatalytic degradation of benzothiophene in
aqueous suspension has been studied.
photocatalysts are prepared by a sol-gel method. The dominant anatase-structure on
particles is observed after calcining the
for 1hr. Photocatalysts with various transition metals (Nd, Pd and Pt) loading are tested to evaluate the effect of transition metal impurities on photodegradation. The photocatalytic degradation in most cases follows first-order kinetics. The maximum photodegradation efficiency is obtained with
dosage of 0.4g/L. The photodegradation efficiency with Pt-
is higher than pure
powder. The optimal content value of Pt is 0.5wt.%. Also we investigate the applicability of
to increase the efficiency of the
photocatalytic degradation of benzothiophene. The optimal concentration of
is 0.05. The effect of pH is investigated; we obtain the maximum photodegradation efficiency at pH 9. Hydroxy-benzothiophenes and dihydroxy-benzothiophenes are identified as reaction intermediates. It is proposed that benzothiophene is oxidized by OH radical to sequentially form hydroxyl-benzothiophenes, dihydroxybenzothiophenes, and benzothiophenedione.
Performance Analysis of WHR-ORC Using Hydrocarbon Mixtures for 20kW Gross Power at Low Temperature
Kwakye-Boateng, Patricia ; Yoon, Jung-In ; Son, Chang-Hyo ; Hui, Kueh Lee ; Kim, Hyeon-Uk ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 140~145
DOI : 10.9726/kspse.2014.18.6.140
Exploitation of renewable energies is on the increase to mitigate the reliance on fossil fuels and other natural gases with rocketing prices currently due to the depletion of their reserves not to mention their diverse consequences on the environment. Divergently, there are lots of industries "throwing" heat at higher temperatures as by products into the environment. This waste heat can be recovered through organic Rankine systems and converted to electrical energy with a waste heat recovery organic Rankine cycle system (WHR-ORC). This study uses the annual average condenser effluent from Namhae power plant as heat source and surface seawater as cooling source to analyze a waste heat recovery organic Rankine cycle using the Aspen HYSYS simulation software package. Hydrocarbon mixtures are employed as working fluid and varied in a ratio of 9:1. Results indicate that Pentane/Isobutane (90/10) mixture is the favorable working fluid for optimizing the waste heat recovery organic Rankine cycle at the set simulation conditions.
Preparation and Electrochemical Characteristics of Mg-Sn Nanoparticles as an Anode Material for Li-ion Batteries
Tulugan, Kelimu ; Lei, Jun-Peng ; Dong, Xin-Long ; Park, Won-Jo ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 146~152
DOI : 10.9726/kspse.2014.18.6.146
Mg-Sn nanoparticles were prepared by an arc-discharge method in a mixture atmosphere of argon and hydrogen gases. Phases, morphologies, and microstructures of the nanoparticles were investigated by means of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). It was found that the intermetallic compound of
was generated and coexisted with metallic phases of Mg and Sn within nanoparticles. Basedon the model cell, the electrochemical properties were also explored by discharge-charge cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. The initial capacity of the first cycle reached 430 mAh/g. Two visible plateaus at 0.2-0.3 and 0.5-0.75V were observed in the potential profiles, which can attributed to alloying/de-alloying reactions between Li and Mg2Sn, respectively.
A Study on a High Efficiency Dryer for Food Waste
Kim, Bum-Suk ; Kang, Chang-Nam ; Jeong, Ji-Hyun ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 153~158
DOI : 10.9726/kspse.2014.18.6.153
The food waste that occurs in one year is very high in our country and disposal is expensive. However, disposers for food waste are not used wisely at real life. This is because most of them some kind of problem, for example big volume, complicated construction, high cost, lots of troubles, low energy efficiency and so on. In this study, we propose the new dryer system to decrease drying times by injecting hot air in down the side of the drying bucket. The designed drying bucket has inclined inlet holes down both sides. The inlet holes have variable gradients, we adjust the inlet velocity of the hot air to find a suitable vortex in the drying bucket. We verify the properties of the proposed system though simulation. The results show the proposed dryer system can improve the drying time and save energy for food waste disposal.
A Study on the Ventilation Method for a Factory with a Sealed Structure
Kim, Yeong-Sik ; Yi, Chung-Seob ; Lee, Dae-Chul ; Jeong, Hyo-Min ; Chung, Han-Shik ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 159~165
DOI : 10.9726/kspse.2014.18.6.159
On this work, the importance of industrial ventilation was investigated and examined the theoretical point and problems about general ventilation of factory exposed on high temperature during summer. As a case study, the ventilation planning of the printed circuit board (PCB) etching process for an electronic company was carried out and each of those characteristics were compared by installing actual ventilation systems and measuring the changing state of the working environment in accordance with ventilation method during summer. The purpose of the study is to present an efficient ventilation method for a factory with a closed structure under high temperature environment. In summary, for a factory with a sealed structure such as the target PCB manufacturing factory in this study, the forced supply and exhaust method was the most appropriate ventilation method for maintaining a low.
Mechanical Behaviors of CFRP Laminate Composites Reinforced with Aluminum Oxide Powder
Kwon, Oh-Heon ; Yun, Yu-Seong ; Ryu, Yeong-Rok ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 166~173
DOI : 10.9726/kspse.2014.18.6.166
In this study, a laminated composite material with dispersing aluminum oxide powder between the CFRP laminate plies, and also CFRP composites without aluminium oxide powder were fabricated for Mode I experiments using the DCB specimen and a tensile test. The behavior of the crack and the change of the interfacial fracture toughness were evaluated. Also in order to evaluate the damage mechanism for the crack extension, the AE sensor on the surface of the DCB test specimen was attached. AE amplitude was estimated for CFRP-alumina and CFRP composite. And the fracture toughness was evaluated by the stress intensity factor and energy release rate. The results showed that an unstable crack was propagated rapidly in CFRP composite specimen along with the interface, but crack propagation in CFRP-alumina specimen was relatively stable. From results, we show that aluminium oxide powder spreaded uniformly in the interface of the CFRP laminate carried out the role for preventing the sudden crack growth.
Friction and Wear of Nano-Sized Silica Filled Epoxy Composites
Kim, Jae-Dong ; Kim, Yeong-Sik ; Kim, Hyung-Jin ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 174~179
DOI : 10.9726/kspse.2014.18.6.174
The wear behavior of epoxy matrix composites filled with nano sized silica particles is discussed in this paper. Especially, the variation of the coefficient of friction and the specific wear rate under the various applied load and sliding velocity were investigated for these materials. Wear tests of pin-on-disc mode were carried out and followed by scanning electron microscope observations. The presence of silica filler in epoxy composites was demonstrated significant influence on the friction and wear behavior of epoxy nanocomposites. With the incorporation of silica filler into the epoxy matrix, reduction of the coefficient of friction and specific wear rate were identified. Wear mechanism was discussed by analyzing the worn surface by scanning electron microscope as well.
A Study on the Structural Characteristics and Shape of Outfitting Equipment Support in a 300K DWT Crude Oil Tanker
Jeong, Kwang-Woon ; Chung, Han-Shik ; Jeong, Hyo-Min ; Ji, Myoung-Kuk ; Kim, Jeong-Tae ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 180~185
DOI : 10.9726/kspse.2014.18.6.180
Due to the larger and high-speed vessels recently constructed, output and speed of the engines for propulsion or power generation is increasing. These high-power and high-speed engine of the ship is becoming as a major contributor causing excessive noise and vibration. Other fittings as well as equipment installed on board, it makes equipment failure or other defect by resonance. This causes a lot of M/H(Man Hour) for repairs and the reliability of the company is invading even be negative because the clients give much comment. Thus, it`s being studied for any fittings installed on board to maintain the safe operation and to prevent any problem during the performance in any operating conditions. In this study, it was investigated to solve these problems for the supports of the various fittings for easy installation-related support that each type of intensity and shape and manufacturing method using structural analysis program(DNV Nauticus Hull 3D Beam). Namely, it would be applied to the very large crude carriers in consideration of mechanics of materials of the support equipment by providing the fact that dynamics analysis of the structural characteristics of the equipment and the support of the production installation is easy and productivity can be high standards for geometry and thereby to simplify the analysis task to design changes at the same time and to minimize the reinforcement for the supports.
The Effects of Chamber Temperature and Pressure on a GDI Spray Characteristics in a Constant Volume Chamber
Oh, Seun-Sung ; Kim, Seong-Soo ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 186~192
DOI : 10.9726/kspse.2014.18.6.186
The spray structures under the stratified and homogeneous charge condition of a gasoline direct injection were investigated in a visualized constant volume chamber. The chamber pressure was controlled from 0.1 MPa to 0.9 MPa by the high pressure nitrogen and the chamber temperatures of
were controlled by the band type heater. The fuel, iso-octane was injected by a 6-hole injector with the pressures of 7 MPa and 12 MPa. From the experiments results, it is confirmed that at lower chamber pressure, the penetration length and spray angle are mainly affected by the chamber temperature with the vaporization of the fuel droplets and generated vortices at the end region of the spray. And at higher chamber pressure, the penetration lengths at the end of the injection were about 50~60% of that at lower chamber pressure regardless of the chamber temperature and the effect of fuel injection pressure is larger than that of the chamber temperature which results from larger penetration lengths at higher fuel injection pressure than at lower fuel injection pressure regardless of the chamber temperatures.
A New Modularized Balancing Circuit for Series Connected Battery cells
Lee, Hyo-Jae ; Jung, Young-Seok ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 193~199
DOI : 10.9726/kspse.2014.18.6.193
The series connected battery cells are mainly used in high voltage battery pack application. However parameter inequality of each battery cell makes battery voltage imbalance problem. In this paper, a new balancing circuit utilizing converter scheme for the series connected battery cells is proposed. Proposed circuit offers easy control and fast equalization time. Moreover the circuit can be used in a practical application because it has high modularity and can operate during the charging/discharging cycle. To show its superiorness and effectiveness, the principle of proposed circuit is explained with computer simulation and experiment is carried out using lithium-ion battery.
PI Controller Design of the Refrigeration System Based on Dynamic Characteristic of the Second Order Model
Jung, Young-Mi ; Jeong, Seok-Kwon ; Yang, Joo-Ho ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 200~206
DOI : 10.9726/kspse.2014.18.6.200
This paper deals with deterministic PI controller design based on dynamic characteristics for refrigeration system. The temperature control system of an oil cooler is described as a typical 2nd order model of the refrigeration system which has zeros in a transfer function. PI controller gains satisfying control specifications are represented by the dynamic characteristic functions using relationship between the parameters and the control specifications in the model. Phase margin was considered to increase robustness of the oil cooler control system. Furthermore, the influence of zeros in the model to the control specifications was analyzed in detail for improving control performance. The validity of the suggested PI controller design was investigated using the four types of gains which had been already confirmed their control performances through experiments.
Study of Mass and Flow Resistance in a Square Ribbed Microchannel using Lattice Boltzmann Method
Taher, Mohammad Abu ; Kim, Heuy-Dong ; Lee, Yeon-Won ;
Journal of the Korea Society For Power System Engineering, volume 18, issue 6, 2014, Pages 207~214
DOI : 10.9726/kspse.2014.18.6.207
Mass and flow resistance in a square ribbed microchannel have been studied numerically using the Lattice Boltzmann Method. It has been build up on two dimensional nine velocity vectors model with single relaxation time method called the Lattice Bhatnagor-Gross-Krook model. To analyze the roughness effect on the flow resistance namely the friction factor and mass flow has been discussed at the slip flow regime,
, where Kn is the Knudsen number. The wall roughness is considered by square microelements with a relative roughness height up to maximum 10% of channel height. The velocity profiles in terms of streamlines near the riblets are demonstrated to be responsible for the roughness effect. It is found that the roughness effect leads to increase the flow resistance with roughness height but it is decreased significantly with increasing the space between two roughness elements as well as the Knudsen number. In addition, the mass flow decreased linearly with increasing both roughness height and gap but significantly changed at the slip flow regime.