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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
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Effect of Ultrasonic Energy in the Engine using Diesel Fuel Blended Rape-seed Oil
Kwon, K.R. ; Ko, K.N. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 5~10
The effect of ultrasonic energy for diesel fuel and blend oil has been revealed in this paper. The experimental setup consisted of a high speed diesel engine with 4 cylinder, dynamometer and ultrasonic fuel feeding system. Ultrasonic energy was added to diesel fuel and blend oil, which is a blend of diesel fuel and rape-seed oil. As engine speed was changed, engine torque and power, brake specific fuel consumption and thermal efficiency were measured in detail. As the results, by adding ultrasonic energy to diesel fuel and blend oil, the engine performance was improved in range of the experiment. The effect of improvement on brake specific fuel consumption and thermal efficiency for blend oil is higher than that for diesel fuel. When ultrasonic energy was added to diesel fuel or blend oil, a rise in engine torque for diesel fuel was higher than that for blend oil, but the effect of ultrasonic energy was small. From these results, it may be desirable to add ultrasonic energy to blend oil for the use of blend oil to diesel engine.
Study on the Performance of Total Heat Exchanger with Rotating Porous Plates
Cho, D.H. ; Lim, T.W. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 11~17
This paper reports an experimental study on the performance evaluation of air-to-air heat exchanger with rotary type newly developed in this study. Air flow rate is varied from 10 to 120 m3/h. The range of RPM of the porous rotating discs mounted inside the heat exchanger unit is 0 to 50. The temperature of the return air side is set by adjusting heat supply at heater. The material of the porous rotating discs is cooper and its thickness is 1.0 mm. The heat transfer rate increased with the increase in air flow rate. It was found that the heat transfer rate, as the temperature of the return air side was increased, was improved due to higher temperature difference. The heat exchange performance increased with the increase in the temperature of the return air side at the conditions of the same RPM. The sensible heat exchange efficiency was maximum 68 to 76 percent, and enthalpy exchange efficiency 64 to 74 percent.
Study on the Performance of Total Heat Exchanger with Rotating Porous Plates
Lim, T.W. ; Cho, D.H. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 18~23
The experimental investigation was carried out to evaluate the performance of air-to-air heat exchanger with rotating porous plates newly developed in this study. The rotating porous plates are mounted with an equal interval of 18 mm inside the heat exchanger where the hot and cold airs enter at opposite ends. When flowing in opposite directions by the separating plate installed in the center of the rotating porous plates, the airs give and receive the heat each other. The material of the porous plate is cooper and its thickness is 1.0 mm. Air flow rate is varied from 10 to 120 m3/h. From the experiment of air-to-air heat exchanger with the rotating porous plates, the heat exchange performance increased with the increase in RPM of the porous rotating discs at the conditions of the same air flow rate. The sensible heat exchange efficiency was maximum 60 to 70 percent, and enthalpy exchange efficiency 50 to 60 percent.
Numerical Simulation of Oil Supply System of Reciprocating Compressor for Household Refrigerators
Kim, H.J. ; Lee, J.K. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 24~30
For a reciprocating compressor of household refrigerators, a direct analogy between the pipe flow network and the electric circuit network has been utilized to set up a mathematical model for oil supply system. Individual lubrication elements of the oil supply system, such as propeller- installed oil cap, oil galleries, radial oil feeding holes, spiral oil grooves, and various sliding surfaces have been analogized by equivalent electric elements, and these have been combined together to form an electric circuit corresponding to the whole oil supply system. By solving the closed network equations of the model, oil flow rates at various lubrication elements could be obtained. Total amount of the oil flow rate drawn into the shaft has been measured and compared reasonably well with the prediction of the numerical simulation.
Characteristics on the Thermal and Fluid Flow in the Rectangular Aquarium Basin by Using PIV
Kim, B.H. ; Konar, Dibyendu ; Jeong, H.M. ; Chung, H.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 31~38
Energy Loss and Flow Rate at Junction Pipe
Kim, M.K. ; Kwon, O.B. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 39~44
This paper presents the study of flows at T-junction pipe with orifices. Experiments were carried out for several flow rates, orifice sizes, and pressure differences. Numerical simulations were also done to get more data for the wide range of flow rates. Experimental results and numerical ones are in a good agreement. Due to the effect of T-junction part, the flow rates at the lateral pipe are greater than those at straight pipe for the same pressure differences. When orifices were added, the effects of T-junction part on the ratio of flow rates and the ratio of loss coefficients reduced.
Flow Characteristics for PIV Visualization at Junction Duct
Kim, M.K. ; Kwon, O.B. ; Bae, D.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 45~50
Characteristics of flows at T-junction duct with and without orifices are investigated in this paper. Experiments and PIV visualization were carried out for several flow rates. Two-dimensional PIV experimental apparatus was decided by numerical analysis. PIV visualization was also coded to visualize flow fields at junctions for two-dimensional case. For the PIV visualization system, Grey-Level Cross-Correlation particle tracking algorithm was used to calculate the flow fields. Vinyl chloride polymer particles of
of diameter are used in this visualization. The PIV visualization results showed relatively good agreement with Experimental data.
Numerical Analysis of the Inner Flow of a 3-pass Rotary Dryer
Kim, T.S. ; Kim, Y.K. ; Choi, Y.H. ; Choi, K. ; Lee, Y.W. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 51~57
In order to prevent the environmental pollution, the dryers are commonly used to treat sludge that one of sewages is polluting the quality of water. Generally, the drying method is various as to the property of material and use. Rotary dryer is a good apparatus to treat them. The rotary dryer is the way that is to make substance transmission and heating using hot air between sludge particles and heated gas. In this paper, we performed a numerical analysis of the inner air flow of the 3-pass rotary dryer through the changing rotational speed from 3rpm to 10rpm. In this result, we found that 3rpm is effective to dry material in terms of heat transfer because large scale velocity fluctuation is occurred inside the first and second drum. Also we confirmed that 5rpm and 8rpm showed up uniform flow at the center area of the first drum.
Parametric Sensitivity Analysis Using Fourier Transformation
Baek, Moon-Yeal ; Lee, Kyo-Seung ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 58~64
Vibration Analysis of a Water Tank Structures
Bae, S.Y. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 65~70
A liquid storage rectangular tank structures are used in many fields of civil, mechanical and marine engineering. Especially, Ship structures have many tanks in contact with inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tank structures. Many authors have studied vibration of cylindrical and rectangular tanks structures containing fluid. Few research on dynamic interaction among tank walls through fluid are reported in the vibration of rectangular tanks recently. In case of rectangular tanks, structural coupling between adjacent panels and effect of vibration modes of multiple panels on added mass have to be considered. In the present paper, coupling effect between panels of tank structure on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region have investigated numerically and experimentally.
The Effect of Added Mass of Water and Breath Mode in Fluid-Structure Coupled Vibration Analysis
Bae, S.Y. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 71~76
Marine structures are often in contact with inner or outer fluid as stern, ballast and oil tanks. The effect of interaction between fluid and structure has to be taken into consideration when we estimate the dynamic response of the structure appropriately. Fatigue damages can also be sometimes observed in these tanks which seem to be caused by resonance. Thin walled tank structures in ships which are in contact with water and located near engine or propeller where vibration characteristics are strongly affected by the added mass of containing water. Therefore it is essentially important to estimate the added mass effect to predict vibration characteristics of tank structures. But it is difficult to estimate exactly the magnitude of the added mass because this is a fluid-structure interaction problem and is affected by the free surface, vibration modes of structural panels and the depth of water. I have developed a numerical tool of vibration analysis of 3-dimensional tank structure using finite elements for plates and boundary elements for fluid region. In the present study, the effect of added mass of containing water, the effect of structural constraint between panels on the vibration characteristics are investigated numerically and discussed. Especially a natural frequencies by the fluid interaction between 2 panels and a breath mode of the water tank are focused on.
A Numerical Analysis Study on Evaluation of the Reliability for Bellows in the Vehicle Exhaust System
Lee, S.H. ; Sim, D.S. ; Oh, S.G. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 77~82
Bellows is a familiar component in piping systems as it provides a relatively simple means of absorbing thermal expansion and providing system flexibility. In routine piping flexibility analysis by finite element methods, bellows is usually considered to be straight pipe runs modified by an appropriate flexibility factor; maximum stresses are evaluated using a corresponding stress concentration factor. In this paper, the dynamic characteristics of bellows were investigated by Finite element methods. Using Anany program, the natural frequencies and evaluation of the reliability of bellows were also investigated.
The Behavior of Shrinkage on PMMA in Injection Molding Compression Molding
Choi, Y.S. ; Han, S.R. ; Jeong, Y.D. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 83~89
Molding shrinkage is one of the problems to be solved in conventional injection molding. Despite many trying-out has been to solve it, intrinsic cause of shrinkage such as orientation and thermal exchange between melt and mold has not been solved yet. For reducing shrinkage and residual stress on molding, injection compression molding process was invented. In this study, experiments about effects of injection compression molding's parameters on shrinkage of PMMA molding were conducted and compared with conventional injection molding's shrinkage. Before the injection compression molding experiment, molding shrinkage rate was predicted by analyzing pvT diagram and was compared with the results of experiment. The shrinkage rate of injection compression molding was lower than convention injection molding's one which was different from the predicted shrinkage. The reason was observed that the experimental mold was not a proper type for injection compression, flowing backward of melt into nozzle and unreasonable mechanism of injection molding machine.
Fundamental Study on the Formation of Nanostructured Coating Layer
Kim, Y.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 90~95
The wire-arc process is a low-cost thermal spray method simply utilizes electrical energy to melt the feedstock wire. It is more userful for field applications, especially to coat large surface area. In this paper, a special Fe-based alloy coatings by using the wire-arc process were developed. Nanoscale composite coatings were achieved either during spraying or through a post heat treatment. As-sprayed Fe-based alloy coatings had been an amorphous matrix structure, after heating to
for 10 minutes a solid state transformation occurred in the some fraction of amorphous matrix which resulted in the formation of nanostructured recrystallized phase. Scanning electron microscopy (SEM) and field emotional scanning electron microscope(FE-SEM) were applied to analyze the microstructure of the coatings. Additionally hardness and bend resistance of the Fe-based alloy coatings were examined, and these results were compared with those of partially stabilized zirconia(PSZ) coatings by using the plasma spray process.
A Study on the Characteristics of High Temperature and Mechanisms for Creep Deformation of AZ31 Mg Alloy
Kang, D.M. ; An, J.O. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 96~101
Magnesium alloys have been widely used for many structural components of automobiles and aircraft because of high specific strength and good cast ability in spite of hexagonal closed-packed crystal structure of pure magnesium. In this study, uniaxial tension tests at high temperature and creep tests are done in order to investigate the characteristics of high temperature and mechanisms for creep deformation of AZ31 Mg alloy. Yield stress and ultimate tensile stress decreased with increasing temperature, but elongation increased from results of uniaxial tension test at high temperature. The apparent activation energy Qc, the applied stress exponent n and rupture life have been determined during creep of AZ31 Mg alloy over the temperature range of 473K to 573K and stress range of 23.42 MPa to 93.59 MPa, respectively, in order to investigate the creep behavior. Constant load creep tests were carried out in the equipment including automatic temperature controller, whose data are sent to computer. At around the temperature of
and under the stress level of
, and again at around the temperature of
and under the stress level of
, the creep behavior obeyed a simple power-law relating steady state creep rate to applied stress and the activation energy for the creep deformation was nearly equal, respectively, and a little low to that of the self diffusion of Mg alloy including aluminum. Also rupture surfaces at high temperature have had bigger dimples than those at lower temperature by SEM.
A Study on Fatigue Life of Weld Method for Excavator Bucket
Park, K.D. ; Jung, J.W. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 102~109
An attachment part of the construction equipment frequently claimed from the crack occurrence that takes especially at the bucket. therefore we execute the fatigue examination and changes the welding method at the same materials. we executed a fatigue crack propagation experiment and got the conclusions at the normal temperature and Frequency 10Hz. We carried out butt welding for structure steel of SM490A and make three kinds of specimen of different weld method each. The fatigue limit of CASE 1 was determined to the low than CASE 2, CASE 3. the CASE 2 putting the interval of the 2mm creates back plate and make fatigue limit to high. Bead shapes and weld surfaces shape influence on fatigue life of materials. Specially, the crack growth becomes starting point that gap of back-plate and boundary surface of bead. It is confirmed by fracture showing on this study.
A Study on the Corrosion Properties of Underwater Wet Arc Welds Using the SM 41
Kwak, H.H. ; Ki., C.G. ; Kim, M.N. ; Hwang, S.H. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 110~117
Underwater wet arc welds were experimentally performed on 11mm thick KR-RA steel plate using six different types of flux coated electrodes of 4.0mm diameter, KSKR, KSKT, USBL, JPUW, UWEA and UWEB. From analysis of bead appearance, detachability of weld slag, spatter occurrence and arc stability, JPUW gives the best result, and UWEB is superior to KSKR and KSKT. By experimental result of hardness distribution on the weld bonds, UWEB weld has the narrowest bond structure which is probable condition to get the best mechanical properties of weld. UWEB and JPUW welds have more even hardness distribution across weld deposit and base metal. Upon polarization test to measure the respondency of corrosion, the electrode of UWEB shows the most excellent degree due to the low open circuit potential difference.
Optical Properties of Silicon Nanoparticles and
Thin Films Prepared by Pulsed Laser Ablation
Kim, M.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 118~123
We have investigated the fabrication of Si nanoparticles and
thin films by pulsed laser ablation. By atomic force microscopy(AFM), the laser-deposited
thin film was verified to have surface far smoother than the surfaces of films produced by the conventional evaporation method. The Si deposited at a He atmosphere of 0.2 Torr was with about
height of the Si nanoparticles, suggesting that it was uniformly deposited. We observed visible green emissions spectra in the
multilayer films after laser annealing. It is considered that this green emissions is occurred from SiC particles, which is produced reaction of Si nanoparticles with
by laser annealing.
Preparation of the Copper Oxalate Powder by Ethanol Oxalic Acid Method
Choi, H.L. ; Lee, B.W. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 124~129
Copper oxide, CuO, are very important components include of high temperature super- conductors, and widely used. The properties of sintered materials were affected by the size and shape of copper oxide with starting materials in the solid-phase reaction. A homogeneous and fine CuO powder was prepared by thermal decomposition of the copper oxalate precursor. Copper oxalate was precipitated by the addition of copper nitrate solution to an oxalic acid solution. The influence of various factors such as temperature, pH, concentration as well as ultrasonic irradiation in the solution were investigated.
Effects of Processing Parameters on the Mechanical Properties of Aluminium Matrix Composites
Kim, J.D. ; Koh, S.W. ; Kim, H.J. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 130~136
The effects of additional Mg content, the size and volume fraction of reinforcement phase on the mechanical properties of ceramic particle reinforced aluminium matrix composites fabricated by pressureless metal infiltration process were investigated. The hardness of
composites increased gradually with an increase in the additive Mg content, while the bending strength of
composites increased with an increase in additive Mg content up to 5%. However, this decreased when the level of additive Mg content was greater than 5% due to the formation of coarse precipitates by excessive Mg reaction and an increase in the porosity level. The hardness and strength of the composites increased with decreasing the size of SiC particle. It was found that the composites with smaller particles enhanced the interfacial bonding than those with bigger particles from fractography of the composites. The hardness of
composites increased gradually with an increase in the volume fraction, however, the bending strength of
composites decreased when the volume fraction of alumina particle was greater than 40% owing to the high porosity level.
A Study on the Impact Fracture Behavior of Side Plate of 35 Ton Class FRP Ship
Kim, H.J. ; Lee, J.J. ; Koh, S.W. ; Kim, J.D. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 137~142
The effects of temperature and initial crack length on impact fracture behavior of side plate material of 35 ton class FRP ship, which are composed by glass fiber and unsaturated polyester resin, were investigated. Impact fracture toughness of GF/PE composites displayed maximum value when the temperature of specimen is room temperature and
, and with decrease in temperature of specimen, impact fracture toughness decreased. Impact fracture energy of GF/EP composites decreased with increase in initial crack length of specimen, and this value decreased rapidly when the temperature of specimen is lowest,
,. It is believed that sensitivity of notch on impact fracture energy were increased with decrease in temperature of specimen. As the GF/EP composites exposed in low temperature, impact fracture toughness of composites decreased gradually owing to the decrease of interface bonding strength caused by difference of thermal expansion coefficient between the glass fiber/polyester resin. Further, decrease of interface bonding strength of composites with decrease in specimen temperature was ascertained by SEM photograph of impact fracture surface.
A Study of Mechanical Properties on High Density Graphite Products with Expanded Graphite(1)
Shin, Y.W. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 143~147
Graphites is well known to have superior advantages to high-temperature, high-pressured, and strong acid-state gas or liquid because it is very stable and chemical structure. Nowadays the new plant with high performance is developed in field of chemical industries, so the need of graphites is increasing rapidly. In this paper, newly developed graphite products with high density is investigated by the mechanical properties of that. I introduced the graphite material which developed for this experiment by the forming process in order to compare to the commercial graphite sheet from expanded graphite which made by the rolling process. Through measuring density and hardness test also tensile test, I investigated the characteristics of these materials. It is verified that the newly developed graphite products forming method is able to make graphite products which have superior mechanical properties than that of commercial graphite sheet.
A Study on Thermostable Property of High Density Graphites Products with Expanded Graphite(1)
Shin, Y.W. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 148~154
Thermostable property is one of most important characteristics of graphite. Commercial graphites sheet from expanded graphite is using for high-temperature elements. Nowadays the new plant with high performance is developed in field of chemical industries, so the need of graphites is increasing rapidly. In this paper, the thermostable properties of newly developed graphite products with high density is investigated. I introduced the graphite material which developed for these heat tests by NGF method in order to test thermostable properties by comparing to the results of the commercial graphite sheet from expanded graphite in same condition. Through measuring the weight reducing ratio with various specimens in some conditions, I investigated the thermostable characteristics of these materials. It is verified that the graphite products by NGF method has almost same or superior thermostable properties comparing with that of commercial graphite sheet. Also the graphite products by NGF method have possibility of being better in thermostable properties.
Automation of Governor Performance Test System
Lee, I.Y. ; Kim, J.W. ; Kang, M.G. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 155~161
Governors control the revolution speed of heat engines such as diesel engines, steam turbines and gas turbines. Precise and prompt tests for the control performances of governors are essential both in governors' manufacturing processes and in governors' maintenance processes. In the conventional governor test systems controlled by analog type electronic controllers, the incorporation of heat engine's dynamics to the test system have been considered very difficult to realize. This study suggests a new governor test system controlled by a digital controller using a personal computer. The application of the digital controller to the test system instead of the analog type electronic controller have brought about the following advancements; (1) heat engine's dynamics could be implemented easily in the test system, (2) automatic test data acquisition both in steady state and in transient state enables us to save test time and to enhance the reliability of the tests.
Characteristics Improvement of a PZT Actuator for Metal Printing
Yun, S.N. ; Ham, Y.B. ; Kim, C.Y. ; Park, P.Y. ; Kang, J.H. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 162~167
The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that are cost less and faster than previous semiconductor processes have been developed for the production of electric paper and RFID(Radio Frequency IDentification). The system proposed in this study prints by spraying the molten metal. And this system consist of a nozzle, heating furnace, operating actuator and an XYZ 3-axis stage. As an operating system, the piezoelectric(PZT) actuator is a very useful tool for position control of the metal printing system. However, the PZT actuator has a hysteresis nonlinearity due to the ferroelectric characteristics of the PZT element. This hysteresis causes problem position control characteristics in the system and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. In order to reduce the hysteresis nonlinearity of the PZT actuator, this proposed a inverse hysteresis model and a mathematic modeling method that can express the geometric relationship between voltage and displacement. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good tracking performance.
Coreless Electronic Transformer
Seo, J.H. ; Kim, M.G. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 168~174
A coreless electronic transformer is proposed. Conventional iron cored transformer is heavy and bulky and it has substantial amount of no load loss. On the other hand, electronic transformer can be made of negligible no load loss and is small size and lightweight. It consists of rectifier and PWM inverter. Electronic transformer is easily modeled to conventional Buck converter; therefore, output voltage is controlled by duty ratio. It is thought to be suitable for applications where the operation duty is low. In this paper, a novel coreless transformer is proposed, then it's detailed analysis, simulative and experimental results are presented
Design of Adaptive Discrete Time Sliding-Mode Tracking Controller for a Hydraulic Proportional Control System Considering Nonlinear Friction
Park, H.B. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 175~180
Incorrections between model and plant are parameter, system order uncertainties and modeling error due to disturbance like friction. Therefore to achieve a good tracking performance, adaptive discrete time sliding mode tracking controller is used under time-varying desired position. Based on the diophantine equation, a new discrete time sliding function is defined and utilized for the control law. Robustness is increased by using both a recursive least-square method and a sliding function-based nonlinear feedback. The effectiveness of the proposed control algorithm is proved by the results of simulation and experiment.
The Development of Industry Operation Control System using Intelligent Web Monitoring for the Heat Treatment Process
Oh, J.H. ; Bae, H.J. ; Choi, G.S. ; Ahn, D.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 181~186
Because of advanced control technology, Shop floor control system of various kinds of equipment and machinery need a web based remote monitoring to control process efficiently. This paper presents the development of Operation Control System. Operation Control System(OCS) is based on intelligent web monitoring, so that OCS is improved the working condition for the line of heat treatment process and the product's quality. The developed OCS is consisted of Atmega128(MCU) based on embedded system, running the data logging of the line of heat treatment process. Web monitoring system is based on CS8900 ethernet controller and TCP/IP for remote monitoring responsibility between a server and clients and controlling the progress of entire system. The developed OCS is implemented on the line of heat treatment process and shows the improvement of environment condition, product's quality and efficiency of process line.
Fault Diagnosis of a Refrigeration System Based on Petri Net Model
Jeong, S.K. ; Yoon, J.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 187~193
In this paper, we proposes a man-machine interface design for fault diagnosis system with inter-node search method in a Petri net model. First, complicated fault cases are modeled as the Petri net graph expressions. Next, to find out causes of the faults on which we focus, a Petri net model is analyzed using the backward reasoning of transition-invariance in the Petri net. In this step, the inter-node search method algorithm is applied to the Petri net model for reducing the range of sources in faults. Finally, the proposed method is applied to a fault diagnosis of a refrigeration system to confirm the validity of the proposed method.
A Study on Driving Control of an Autonomous Guided Vehicle Using Humoral Immune Algorithm(HIA) Adaptive Controller
Lee, K.S. ; Suh, J.H. ; Lee, Y.J. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 194~201
In this paper, we propose an adaptive mechanism based on humoral immune algorithm and neural network identifier technique. It is also applied for an autonomous guided vehicle (AGV) system. When the immune algorithm is applied to the PID controller, there exists the case that the plant is damaged due to the abrupt change of PID parameters since the parameters are almost adjusted randomly. To slove this problem, we use the neural network identifier technique for modeling the plant humoral immune algorithm (HIA) which performs the parameter tuning of the considered model, respectively. Finally, the experimental results for control of steering and speed of AGV system illustrate the validity of the proposed control scheme. Also, these results for the proposed method show that it has better performance than other conventional controller design method such as PID controller.
Optimum Design of Frame Structures Using Generalized Transfer Stiffness Coefficient Method and Genetic Algorithm
Choi, Myung-Soo ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 202~208
The genetic algorithm (GA) which is one of the popular optimum algorithm has been used to solve a variety of optimum problems. Because it need not require the gradient of objective function and is easier to find global solution than gradient-based optimum algorithm using the gradient of objective function. However optimum method using the GA and the finite element method (FEM) takes many computational time to solve the optimum structural design problem which has a great number of design variables, constraints, and system with many degrees of freedom. In order to overcome the drawback of the optimum structural design using the GA and the FEM, the author developed a computer program which can optimize frame structures by using the GA and the generalized transfer stiffness coefficient method. In order to confirm the effectiveness of the developed program, it is applied to optimum design of plane frame structures. The computational results by the developed program were compared with those of iterative design.
Effect of the Change in Ambient Gas Density on the Mixture Formation Process in Evaporative Free Diesel Spray
Yeom, J.K. ; Chung, S.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 209~213
The effects of density change of ambient gas on mixture formation process have been investigated in high temperature and pressure field. To analyze the mixture formation process of evaporating diesel spray is important for emissions reduction in actual engines. Ambient gas density was selected as experimental parameter. The ambient gas density was changed from
with a high pressure injection system(ECD-U2). For visualization of the experiment phenomenon, a CVC(Constant Volume Chamber) was used in this study. The ambient temperature and injection pressure are kept as 700K and 72MPa, respectively. The images of liquid and vapor phase in the evaporating free spray were simultaneously taken by exciplex fluorescence method. As experimental results, with increasing ambient gas density, the tip penetration of the evaporating free spray decreases due to the increase in the drag force from ambient gas.
Effect of the Change in Injection Pressure on the Mixture Formation Process in Evaporative Free Diesel Spray
Yeom, J.K. ; Chung, S.S. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 214~219
The effects of change in injection pressure on spray structure in high temperature and pressure field have been investigated. The analysis of liquid and vapor phases of injected fuel is important for emissions control of diesel engines. Therefore, this work examines the evaporating spray structure using a constant volume vessel. The injection pressure is selected as the experimental parameter, is changed from 72MPa to 112MPa by using a common rail injection system(ECD-U2). The images of liquid and vapor phase in the evaporating free diesel spray are simultaneously taken by exciplex fluorescence method. As a result, it can be confirmed that the distribution of vapor concentration is more uniform in the case of the high injection than in that of the low injection pressure.
The Thermal Elasto-plastic Analysis Using Layered Shell Element
Song, H.C. ; Yum, J.S. ; Jang, C.D. ;
Journal of the Korea Society For Power System Engineering, volume 9, issue 4, 2005, Pages 220~224
The thermal elasto-plastic analysis for the prediction of welding distortion of a 3 dimensional large-scaled ship structure is a very time-consuming work since the analysis is a nonlinear problem, and a lot of finite elements are needed to simulate the large ship hull block. Generally, 3-D finite elements have been used in the 3-D welding distortion problem to assess precisely the temperature gradient through the thickness direction of the welding plate. As a result of the adoption of 3-D element, degrees of freedom are rapidly increased in the problem to be solved. In this study, to improve the time efficiency of welding thermal elasto-plastic analysis, a layered shell element was proposed to simulate 3-D temperature gradient, and the results were compared with the experiment. The experiments were carried out for the type of bead-on-plate welding, and we found the measured data have a good agreement with the FEA results.