Proceedings of the Korean Society of Marine Engineers Conference (한국마린엔지니어링학회:학술대회논문집)
The Korean Society of Marine Engineering
- 기타
Domain
- Machinery > Naval Architecture/Ocean Engineering
2000.05a
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The conventional PID controller has been extensively used to speed control of marine diesel engines. However one of drawbacks is that its control performance can be degraded if the parameters are fixed on whole operating points. In this paper a scheme for integrating PID control and the fuzzy technique is presented to control speed of a marine diesel engine on whole operating points. At first the PID controller is designed at each speed mode whose parameters are optimally adjusted using a genetic algorithm, Then fuzzy "if-then" rules combine the controllers as a consequence part. To demonstrate the effectiveness of the proposed fuzzy controller a set of simulation works on a marine diesel engine are carried out.rried out.
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강원룡 6
In this paper a methodology for designing a controller based on inverse dynamics for speed control of DC motors is presented. The proposed controller consists of a low-pass prefilter the inverse dynamic model of a system and the PI controller. The low-pass prefilter prevents high frequency effects from the inverse dynamic model. The model is characterized by a nonlinear friction model. The PI controller regulates the error between the set-point and the system output which is caused by modeling error disturbances and variations f parameters. The parameters of the model and the PI controller are optimized offlinely by genetic algorithm. The experimental results on a DC motor system illustrate the performance of the proposed controller. -
This paper provides a basic study on automatic of a trailer type vehicle which consists of two parts such as a tractor and a trailer Backward moving and parking control is very important to automate this type of vehicle. However it is very difficult to control such their motion since a trailer type vehicle is a non-holonomic system. Therefore in this paper we propose the backward path tracking control algorithm for a trailer type vehicle. And also this paper presents the results of simulation to verify the effectiveness of the proposed control algorithm.
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In this paper we design a GA-fuzzy controller for position control and anti-swing at the destination point. Applied genetic algorithm is used to complement the demerit such as the difficulty of the component selection of fuzzy controller namely scaling factor membership function and control rules. lagrange equation is used to represent the motion equation of trolley and load in order to obtain mathematical modelling. Simulation results show that the proposed control technique is superior to a conventional optimal control in destination point moving and modification.
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This Paper decribes a monitoring system using Modbus protocol and RS485 interface applied in many industrial field. We developed hardware to receive alanlog sensor output and monitoring program to communicate with hardware and carried out experiment with potentiometer for plan sensor, . Through online communication between Master and Slaves we convinced the usage of this systems. Also plant data file that saved in Excel format is convenient in writing various typs of documents.
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For the merit of a container in transportation and cargo handling the amount of container freight has been continuously on the increase. On the other hand container crane had got the bottle neck in cargo handling due to low productivity so that freight congestion had been often occurred at ports. in this paper A mathematical model for container crane system is represented a method for designing a fuzzy controller of container crane system for high productivity in cargo handling is presented. The fuzzy controller is compared with other optimal controller at the same condition. in the computer simulation the fuzzy controller obtained an excellent response to reference change better than the optimal controller. For disturbance such as a strong storm and parameter change due to change of cargo weight the result was also stable and robust than the optimal controller.
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In his study the simulation was carried out by simplifing and modeling dividing into fuel injectioin pump high pressure pipe and fuel injection valve in the fuel injection system of a low speed marine diesel engine. A computer simulation model was developed using the method of characteristics to analyze the unsteady flow in the fuel injection system considering cavitation and variation of fuel density and bulk modulus. Comparison was commenced between the calculated data and experimental data of pressure and injection quantity at the high pressure distributor in fuel injection system for the training ship "M/V hanara" the effects of the high pressure pipe length diameter plunger diameter nozzle openning pressure were also investigated by simulating results.g results.
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Investigators who study on combustion in the cylinders of reciprocating piston type internal combustion engines have been encountered embarrassments due to the difficulties of adjusting specific parameter without interfacing other parameters such as cylinder wall temperature composition of gas in the cylinder existence of cylinder lubricant etc. Rapid compression-expansion machine the position and speed of piston of which are able to be controlled by means of a system controlled electrically and speed of piston of which are able to be controlled by means of a system controlled electrically and actuated hydraulically could be utilized as one of the most preferable countermeasures against those difficulties. Several units of rapid compression-expansion machines were developed but the speed up of frequency of piston movement still is the problem to be improved to cope with actual speed of internal combustion engines. Authors designed and manufactured a new rapid compression-expansion machine electrically controlled hydraulically actuated and computer programed and then examined the performance of one. Results of a set of experiments revealed acquirements of certain improvement of frequency of piston movement preserving the stability of system response and reproducing accurate compression ratio of cylinder those are the key function for the in-cylinder combustion experiments of internal combustion engines.
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Experimental studies were performed to improve the THC emission characteristics by optimizing the flow in the exhaust manifold and CCC in a SI engine. For this purpose the flow characteristics in the exhaust manifold and CCC were measured by using LDV technique under various engine conditions, Referring to these data a new type exhaust manifold was designed to improve the cold-start emission characteristics and the response characteristics of {{{{ OMICRON _2}}}} sensor by optimizing the flow pattern and reducing the thermal inertia of the exhaust manifold system. It was found through the vehicle emission tests that the emission characteristics of THC of the new type exhaust manifold was improved by 12% through the optimizing the flow pattern in the exhaust manifold.
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When the crankshaft of Diesel engine has more than 3 throws which are arranged in a different plane its vibration induces coupled motions especially the coupled torsional and axial vibration. Nowadays the torsional vibration which is influenced rather weak than axial one can be theoretically calculated fairly accurately but theoretical calculation results of the axial vibration which is influenced strongly from torsional vibration is not so good. To get accurate calculation results of axial vibration coupled axial-torsional vibration must be treated. in this investigation coupled effects of vibration of Diesel engine propulsion shafting are analyzed theoretically and some more simple calculation methods are also studied. On this first report effects of coupling on natural frequencies and their modes are mainly studied setting the each mass in 4 degrees of freedom. later this problem may be studied again by setting each mass as 6 degrees of freedom.
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LPG gains many advantages of a high octane number low emissions and low cost over conventional fuel. The fuel has been naturally used in engines to save running cost but the first generation fuel feeding system was not satisfied with stringent requirement for exhaust emissions, A liquid direct injection system into a cylinder has been suggested as a next generation system to maximize a fuel economy as well as to reduce emissions. In this paper LPG sprays are compared with diesel sprays in a high pressured surrounding condition in order to understand the high pressure spray characteristics, The spray images show that LPG spray penetrates further soon after the injection then the sprays stays in a distant. it may explain the flashing effect of LPG.
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Two-phase flow in a combustion chamber is experimentally analyzed according to the five different conditions in the Reynolds number of
$1.02{\times} 10^4$ As the height difference between the primary and secondary jets increases the secondary has a little effect on the primary. In the case of the same height difference the primary jet is affected as the velocity of secondary increases. The primary-jet flow field causes the particle concentration since the particle stagnation phenomena appear in the recirculation zone. The particle concentration is controlled by the velocity of secondary jet the height difference and the angle of primary jet in the test section. -
This study deals with the evaluation of bending fatigue strength in shaving gears, We manufactured gears using manufacture processes that are currently used in most gears manufacturing companies. The test gears are hobbed then the tooth surface are treated by a combination of shaving carbonizing and shot peening. The constant stress amplitude fatigue test is performed by using an electrohydraulic servo-controlled pulsating tester. The S-N curves are obtained and illustrated. In this study we investigated the effect of shaving process and shot peening on fatigue strength, The effect of shaving process ad shot peening on the fatigue strength is evaluated quantitatively,. The enhancement of fatigue strength due to shaving process and shot peening is clarified
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This paper deals with finite element analyses of residual stresses causing popping up which are induced in micromachining processes of a mcroaccelerometers. After heating the tunnel gap up to 100 degree and get it through the cooling process and the additional bean up to 80 degree and get is through the cooling process. We learn the thermal internal stress of each shape and compare the results with each other after heating the tunnel gap up to 400 degree during the Pt deposition process. We want to seek after the real cause of this pop up phenomenon and diminish this by change manufacturing processes of microaccelerometer by electrostatic force.
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Micronization of sensor is a trend of the silicon sensor development with regard to a piezoresistive silicon pressure sensor the size of the pressure sensor diaphragm have become smaller year by year and a microaccelerometer with a size less than 200-300
${\mu}m$ has been realized. In this paper we study some of the micromachining processes of SOI(silicon on insulator)for the microaccelerometer and their subsequent processes which might affect thermal loads. The finite element method(FEM) has been a standard numerical modeling technique extensively utilized in structural engineering discipline for design of SOI wafers. Successful thermal behaviors analysis and design of the SOI wafers based on the tunneling current concept using SOI wafer depend on the knowledge abut normal mechanical properties of the SCS(single crystal silicon)layer and their control through manufacturing process -
This paper shows the possibility of performing the friction stir welding and the development of optimizing tools for FSW with 2mm thick plate of aluminum alloys using milling machine. This research can be reported on achieving above 90% of the tensile strength in 1050 aluminum alloys friction stir welded in the room temperature. This welding process is very simple and does not require filler metal eliminates straightening of the workpiece. It is currently attracting interest from different industries working with aluminum alloys.
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As the development of industry water quality of river is going to bad because of waste water of an industrial complex and general home agricultural chemicals exhaust of
$SO_3$ and CO gas acid rain and so on. Corrosion damage of boiler factory equipment and so forth occur quickly due to using of the polluted water resulting in increasing leak accident. Especially working life of hot water boiler using the polluted water becomes more short and energy loss increases. The cathodic protection method is the most economical and reliable one to prevent corrosion damage of steel structures. Mg-base alloys galvanic anode protection of cathodic protection method is suitable for than application of hot water boiler using water with high specific resistance such as tap water. This paper is studied on the cathodic protection characteristics of how water boiler. In tap water and 0.001mol/$\ell$ NaCl solution the characteristics of anodic polarization of Mg-base alloys galvanic anode and tube material is investigated the measurement of cathodic protection potential according to the time elaspsed is carried out. -
In particle or short-fiber reinforced composites cracking of the reinforcements is a significant damage mode because the broken reinformcements lose load carrying capacity . The average stress in the inhomogeneity represents its load carrying capacity and the difference between the average stresses of the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The composite in damage process contains intact and broken reinforcements in a matrix, An incremental constitutive relation of particle or short-fiber reinforced composites including the progressive cracking damage of the reinforcements have been developed based on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept. influence of the cracking damage on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept. Influence of the cracking damage on the stress-strain response of the composites is demonstrated.
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In the present study flow characteristics of turbulent pulsating flow in a square-sectional 180。 curved duct are investigated experimentally. in order to measure axial velocity and secondary flow distributions experimental studies for air flow are conducted in a square-sectional
$180^{\circ}$ curved duct by using the LDV system with the data acquisition and the processing system of the Rotating Machinery Resolver (RMR) and the PHASE software. The experiment is conducted on seven sections form the inlet(${\phi}=180^{\circ}$ ) at$30^{\circ}$ intervals of the duct. The results obtained from the experimentation are summarized as follows : In the axial velocity distributions of turbulent pulsating flow when the ratio of velocity amplitude(A1) is less than one there is hardly any velocity change in the section except near the wall and any change in axial velocity distribution along the phase. The secondary flow of turbulent pulsating flow has a positive value at the vend angle of$150^{\circ}$ without regard to the ratio of velocity amplitude. The dimensionless value of secondary flow becomes gradually weak and approaches zero in the region of bend angle$180^{\circ}$ without regard to the ratio of velocity amplitude. -
Evaporating heat transfer characteristics of R-22 were measured inside smooth horizontal copper tubes with inner diameters of 3.36 mm and 5.35 mm respectively. The experiments were conducted in the closed loop which was driven by a magnetic gear pump. Experiments were performed for the following range of variables ; mass velocity of refrigerants (200 to 400
$kg/m^2$ .s) saturation temperature ($0^{\circ}C, \; 5^{\circC$ }) and quality (0 to 1.0) The main results obtained are as follows : Evaporating heat transfer coefficients in the small diameter tubes (ID<7 mm) were observed to be strongly affected by a variety of diameters and to differ from those in the large diameter tubes. The heat transfer coefficients of the small diameter tubes are higher than those of the large diameter tubes. Comparing the heat transfer coefficients between experimental results and some well-known previous predictions (Shah's correlation Gungor-Winterton's and Kandlikar's correlation) it was very difficult to apply those to small diameter tubes. -
The objective of experimental study is to apply simultaneous measurement by PIV(Particle Image Velocimetry) to high_speed flow characteristics within ginseng cleaner model. Three different kinds of flow rate(15.20 27ℓ/min) are selected as experimental condition. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. The instantaneous velocity distribution time0mean velocity distribution and velocity profile are represented quantitatively for the deeper understanding of the flow characteristics in a ginseng cleaner model.
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As an improvement in the standard of living and economic growth the demand for air conditioning equipment is increasing rapidly. Nowadays air conditioning equipments are being used for industry large building house and car. Thess equipments was concentrated on improving heat efficiency of economic aspects while they design heat exchanger for cooling and heating,. These air conditioning equipments using heat exchanger cause a discomfort to user due to generating mist at the beginning of operating. Therefore the user demand air of high class and quality. In this experimental study to acquire elementary data for development of heat exchanger which be able to supply air of high quality that is to say possess a restraint effect of mist generation. We estimate an effect on cooling plate kind supply air velocity supply air temperature cooled plate temperature and supply air relative humidity which have an influence on outlet air condition of heat exchanger.
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Flow visualization and PIV measurements were conducted to investigate the flow characteristics of multi-channel with inclination angle. The water flow seeded with tiny vegetable powder as tracers revealed details of flow field. The PIV measurement to acquire multi-point velocity data simulatneously was carried out at three space of plates for 5, 10, and 15mm with variation of inlet flow rates of
$0.25m^3/h$ and<$0.5m^3/h.$ Experiment results show that space of plates acts a significant role in separating process. -
In this paper a new type refrigerant liquid subcooling system which adopts ice storage system is proposed. And the cycle characteristicso of a new system was investigated. Since this system subcools a refrigerant in the daytime using the ice storaged by electric power in the night it is high efficiency heat pump system which have the merit of ice storage system and possible to improve the performance of the heat pump. The running to storage the ie was carried out for 10 hours in the night and th evaporating temperature was set on
$-5^{\circ}C.$ Subcooling operation stayed as430^{\circ}C$ subcooling degree and perfomed till the water in the IST(Ice storage tank) was reached$12^{\circ}C$ . The experimental result showed that a new system was superior to the existing refrigeration system generally. The total cooling capacity of a new system was about 11% higher than that of the existing refrigeration system. And the COP of a new system was improved by 22% compared to the existing refrigeration system. -
A fundamental experimental study for a substitute proposal to super-speed craft propulsion system called underwater ram-jet propulsion by high pressure air ejection as driving force was investigated. for basic study of effect of ram-jet propulsion performances ismple underwater ram-jet flow field was established and PIV(Particle Image Velocimetry) method was adopted to analyse the jet-induced flow appearing at ram intake mixing chamber and nozzle. Some flow dynamics relating to the high-speed ejector effect were discussed for the basic understanding for the ram-jet propulsion principle.
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The worldwide economy has been changing to global and it's going to be put together as one market day by day. In addition the issue of industry has been advanced to automatic and unmanned systems by integration. Thus it is absolutely necessary to be develope and possess high-end technologies to survive in an age of unlimited competition. This development is the core technology of ship unmanned operating system that is very useful and applicable in many fields in addition to ship equipments. Thus it is required to design and develope our own systems which are more reliable compared with foreign products and easy to use and maintenance. We will make an progress of international competitive and contribute to the state economy.