• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.199-202
• /
• 2008

This paper presents a mathematical-physical model to predict the performance of a gas pusher used as a separation system powered by a gas generator. The empirical coefficients of heat loss and friction were determined from experiments. Based on the grain configuration of the gas generator, the analytical approach of combustion, flow and movement of a piston inside the chamber of a gas generator and a gas pusher was simulated by numerical method. The prediction method developed can be usefully applied to the design of separation mechanism systems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.52-57
• /
• 2012

A liquid rocket system consists of a combustion chamber, a gas generator, a turbo pump, and a turbine, etc. Each component is connected by supply components such as valves, pipes, and orifices. Since each component has a combined effect on engine performance, preliminary analysis for overall system must be required before the conceptual design stage. Comprehensive analysis program considered the supply system has not been developed yet. In this paper, a supply component model of the liquid rocket engine has been designed after verification of each component. The gas generator cycle with supply components has been composed. The results of the cycle has been compared to those of the F-1 engine with the representative gas generator cycle.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.1
• /
• pp.10-16
• /
• 2021

This paper systematically investigates and correlates pressure fluctuation and nominal wake characteristics according to the angle of the vortex generators by introducing the angle adjustment method of the Vortex Generator (VG). The vortex generators are installed at the port and starboard of a model ship. The vortex generator performance test is executed on a model ship installed in the Large Cavitation Tunnel (LCT) and the angle of VG is freely controlled by a servo motor. The systematic test results for the vortex generator show that the well-designed VG is an effective appendage for reducing the pressure fluctuation level and shows the direction of VG's angular design optimization.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.2
• /
• pp.112-120
• /
• 2021

The novel wave generating system of a wave flume has been devised by utilizing the analytic solution of wave board motion in idealized two dimensional space. The arbitrary oscillation motion of submerged wave board segment has been defined by sinusoidal motion of upper and lower end of the wave board. The analytic solution of the wave board motion has been represented by the solution of board motion due to flap motion and swing motion. Arbitrary oscillation of the board could be specified by determining amplitude, frequency, and the phase lag. A novel hybrid wave generator could be operated not only in piston motion but also in flap or swing motion by selection of control parameter. The wave generator has unique motion enhancing ability by appending flap motion or swing motion to piston motion in wave generation. In addition the hybrid wave generator has advantages in generating high quality wave spectrum of irregular wave in simulating real sea condition.

• The KIPS Transactions:PartD
• /
• v.11D no.7 s.96
• /
• pp.1477-1482
• /
• 2004

Software development process consists of five phases : requirement, analysis, design, implementation and testing. There is almost always a gap between the system design and implementation stages, caused by a combination of the difficulty of programming and frequent changes on the system design. The goal of this paper is to reduce the gap between system design and implementation, and we design a tool producing a application program by recognizing business logic for a more rapid and flexible developing of software. The core idea of Application Program Generator is : firstly, to recognize that business application in the same domain share business logic and presentation logic : secondly, to treat system design as persistent meta-data ; thirdly, to use the persistent meta-data to build or customize applications as required.

• Korean Journal of Computational Design and Engineering
• /
• v.18 no.3
• /
• pp.224-233
• /
• 2013

For the scheduling and the job assignment of the ship hull production design which is a process-based work, we suggest the simulation-based scheduling using the discrete-event-based business process simulation. First, we analyze the ship hull production design process from the perspective of a job assignment to make it into the simulation model using DEVS (Discrete Event System Specification) which is the representative modeling method for a discrete-event simulation. Based on the APIs of the open-source discrete-event simulation engine, we implement the simulation using the Groovy script. We develop the scenario generator in which the user defines detail information of the construction drawing and its member blocks, and design engineers information, and the various setting for the simulation including the job assignment strategy. We use the XML files from this scenario generator as inputs of simulation so that we can get simulation result in forms of Gantt chart without changes of the simulation model.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.364-367
• /
• 1996

This paper deals with the design and evaluation of the robust controller for generator excitation system to improve the steady state and transient stabilities. The nonlinear characteristics of the system is treated as model uncertainties, and then the robust control techniques are introduced into the PSS design to take into account these uncertainties at the controller design stage. The performance of the designed controller is examined by extensive non-linear time domain simulation. It is shown that the performance of the robust controller is superior to that of the conventional PSS in all cases studied.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.2239_2240
• /
• 2009

This paper describes the design process of three-phase Synchronous generator. stator and rotor were modelled with the result obtained from loading distribution on the provided specification. For proving validity of the result obtained from loading distribution, through Maxwell simulator the first test target values, output and efficiency, Rated speed and etc, were compared with the design result.

• Proceedings of the KIEE Conference
• /
• 1998.11c
• /
• pp.959-961
• /
• 1998

In this paper, we present design rule of high-voltage rectangular generator working in wide band frequency domain. Though power electronics now have voltage ratings up to several kV, it is difficult to design and fabricate high-voltage systems with the power electronic devices alone. So we have combined IGBT with technically designed transformer to get the high-voltage rectangular waveforms. In this work, next two things are the main factors. The first one is design of transformer working low-frequency domain of less than 10Hz. And the second one is adding offset voltage part. As a result, we can get variable frequency high-voltage rectangular waveform and this can be used as a voltage source of sandpaper manufacturing process.

• Journal of The Korean Digital Architecture Interior Association
• /
• v.9 no.3
• /
• pp.15-23
• /
• 2009

Chaos theory, qualitative study of unstable aperiodic behavior in deterministic nonlinear dynamical systems, is dominant paradigm in the twenty first century. Fractal geometry, as an expressed form of chaos, now influences many areas such as architecture, art, music, economics, literature, etc. The purpose of this study is to analyze fractal geometry and fractal formative elements in architectural design. There are scaling, superimposition, distortion, deformation and repetition in the fractal form generator that can be applied to design concept and process in architecture. This study shows fractal geometry can be the architectural form creation method. Fractal geometry similar to nature's patterned order can be provided endless possibilities for design analysis and methodology in architecture. Therefore the further study of fractal geometry should progress synthetically through the basis of the study.