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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
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Volume & Issues
Volume 19, Issue 4 - Aug 1995
Volume 19, Issue 3 - Jun 1995
Volume 19, Issue 2 - Apr 1995
Volume 19, Issue 1 - Feb 1995
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A Study on the Design of Liquid Flow Control Valves for the Plants and Ships
Journal of the Korean Society of Marine Engineering, volume 19, issue 1, 1995, Pages 28~35
The fluid flow for a energy transfer is essential for the design and operation of power plants, petrochemical plants and ships including a process. When the operating conditions of a plant are changed or any transitional event occured, the flow controls of a fluid must be performed to follow the new operating state or mitigate the results of a event. Generally these flow controls to accommodate the new operating state of a plant are made by the use of various valves. The refore the design of valves and the related techniques are very important to the system and component designs. However the system and component design are not familiar with the practical theory of the valve since the derivative procedures of the flow equations in a valve are difficult and it is not easy to found the theoretical foundamentals and informations about the design of a valve from the present references. In this study the flow equations applicable to a valve for liquid are theoretically derived in detail. And the definition of valve reynolds number and its boundary values between the tubulent and laminar flow is described compared with the values of a circular pipe flow.
Melting Heat Transfer of Liquid Ice in a Rectangular Vessel with Heated Top Wall
Journal of the Korean Society of Marine Engineering, volume 19, issue 1, 1995, Pages 36~44
Melting characteristics of unrestrained liquid ice in a rectangular vessel with heated top wall were investigated experimentally. The liquid ice, a mixture of ice particles and ethylene-glycol aqueous solution, was adopted as a testing material. During the melting process the liquid ice was drawn by buoyancy to the heated top wall of the rectangular vessel where close-contact melting occured. The melting behavior and melting rate of the liquid ice as well as local/mean heat-transfer coefficient at the heated top wall were observed and measured under a variety of conditions of heat flux and various initial concentration of the aqueous binary solution. It was found that the heat transfer of the heated top wall is remarkably promoted by the close-contact melting, and that the dendritic frozen layer at the lower interface of the liquid ice is formed. Photographic evidence demonstrated that plumes containing solute-rich liquid issued from isolated chimneys within the liquid ice layer where segregation of interstitial channel took place.
A Study on Prediction of Cutting Temperature in Flank Face ar High Speed Steel
Journal of the Korean Society of Marine Engineering, volume 19, issue 1, 1995, Pages 45~53
Temperature distribution on flank face in orthogonal turning with cutting tool of high speed steel is studied by using a finite element method and experiments. Experiments are carried out to verify the validity of the temperature measurement by using a thermoelectric couple junction imbedded in a cutting tool of high speed steel. Good agreement is obtained between the analytical results and the experimental ones for the temperature distributions on flank face of cutting tool with high speed steel. The analytical results show that the temperature on the top flank face of a tool is higher because of the difference of the friction velocity on each face of the tool.
A study on CAM System for Machining of Sculptured Surface in Mold Cavity(2) -Machining Algorithm and Construction of the System-
Journal of the Korean Society of Marine Engineering, volume 19, issue 1, 1995, Pages 54~59
In this paper, we propose unique CAM system for personal computer that can define the geometric shape in an ease manner and to machine the sculptured surfaces of a mold cavity. In this CAM system, if a user inputs simple initial information such as the control points for a shape definition and a radius of tool etc., all of the procedures for machining will be processed automatically by the CAM system as well as NC commands and simulations. In addition to this, the environment of the CAM system is composed of "C" language for an easy extention of aditional modules. Also, the CAM system with the following characteristics was developed. 1. The optimum tool path satisfying given tolerance limits reduces the time for the high precision machining of sculptured surface in a mold cavity. 2. The generated NC commands can be transmitted to NC directly by the CAM system through RS-232C from PC.C from PC.
A speed controller design for low speed marine diesel engine by the
Journal of the Korean Society of Marine Engineering, volume 19, issue 1, 1995, Pages 60~70
In the field of marine transportation the energy saving is one of the most important factors for profit. In order to reduce the fuel oil consumption the ship's propulsion efficiency must be increased as much as possible. The propulsion efficiency depends upon a combination of an engine and a propeller. The propeller has better efficiency as lower rotational speed. This situation led the engine manufacturers to design the engine that has lower speed, longer stroke and a small number of cylinders. Consequently the variation of rotational torque became larger than before because of the longer delay-time in the fuel oil injection process and an increased output per cylinder. As this new trends the conventional mechanical-hydrualic governors for engine speed control have been replaced by digital speed controllers which adopted the PID control or the optimal control algorithm. But these control algorithms have not enough robustness to suppress the variation of the delay-time and the parameter pertubation. In this paper we consider the delay-time and the perturbation of engine parameters as the modeling uncetainties. Next we design the controller which has zero offset in steady state engine speed, based on the two-degree-of-freedom control theory and
-synthesis. Thd validity of the controller is investigated through the response simulation. We use a personal computer and an analog computer as the digital controller and the engine (plant) part respectively. And, we certify that the designed controller maintains its performance even though the engine parameters may vary.
A study on the design and the analysis of hybrid RSPWM inverter
Journal of the Korean Society of Marine Engineering, volume 19, issue 1, 1995, Pages 71~81
In this paper, a new speed control scheme for induction motor drives that regular sampled PWM and harmonic elimination switching pattern over the full range of output speed is presented. The proposed scheme(hybrid scheme) provides three mode and guarantees smooth voltage boost. A detailed description of the scheme, along with the relalization aspect, is described. Moreover, methods of compensating for dead time and optical transmission system of drive signal are proposed and investigated. Finally, experimental investigation of hybrid scheme is presented.