• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.10
• /
• pp.1297-1302
• /
• 2014

This paper presents modern optimization methods for determining the optimal parameters of proportional-integral-derivative (PID) controller for coupled tank systems. The main objective is to obtain a fast and stable control system for coupled tank systems by tuning of the PID controller using the Particle Swarm Optimization algorithm. The result is compared in terms of system transient characteristics in time domain. The obtained results using the Particle Swarm Optimization algorithm are also compared to conventional PID tuning method like the Ziegler-Nichols tuning method, the Cohen-Coon method and IMC (Internal Model Control). The simulation results have been simulated by MATLAB and show that tuning the PID controller using the Particle Swarm Optimization (PSO) algorithm provides a fast and stable control system with low overshoot, fast rise time and settling time.

• Fire Science and Engineering
• /
• v.25 no.6
• /
• pp.39-43
• /
• 2011

In this research, full-scale fire test was performed on a real house for the evaluation of the performance of waterworks direct-coupled sprinkler system. The fire was set to occur as spontaneous combustion as the cooking oil overheats. The size of house is $56m^2$ and it consists of a living room, a kitchen, and a room. In order to verify the performance of waterworks direct-coupled sprinkler system, it was installed in the kitchen. The result of the test showed that the fire started from the kitchen enlarged up to its ceiling but it was soon exhausted as the sprinkler started to work. The pressure of the waterworks was 0.28 MPa when the sprinkler operated, by which it verified that fire could go out even by waterworks pressure of the general residence.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.3181-3188
• /
• 2008

The supercritical $CO_2$ Brayton cycle energy conversion system is presented as a promising alternative to the present Rankine cycle. The principal advantage of the S-$CO_2$ gas is a good efficiency at a modest temperature and a compact size of its components. The S-$CO_2$ Brayton cycle coupled to a SFR also excludes the possibilities of a SWR (Sodium-Water Reaction) which is a major safety-related event, so that the safety of a SFR can be improved. KAERI is conducting a feasibility study for the supercritical carbon dioxide (S-$CO_2$) Brayton cycle power conversion system coupled to KALIMER(Korea Advanced LIquid MEtal Reactor). The purpose of this research is to develop S-$CO_2$ Brayton cycle energy conversion systems and evaluate their performance when they are coupled to advanced nuclear reactor concepts of the type under investigation in the Generation IV Nuclear Energy Systems. This paper contains the research overview of the S-$CO_2$ Brayton cycle coupled to KALIMER-600 as an alternative energy conversion system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.3
• /
• pp.50-64
• /
• 2011

In this paper, a DC-coupled photovoltaic (PV), fuel cell (FC) and ultracapacitor hybrid power system is studied for building microgrid. In this proposed system, the PV system provides electric energy to the electrolyzer to produce hydrogen for future use and transfer to the load side, if possible. Whenever the PV system cannot completely meet load demands, the FC system provides power to meet the remaining load. The main weak point of the FC system is slow dynamics, because the power slope is limited to prevent fuel starvation problems, improve performance and increase lifetime. A power management and control algorithm is proposed for the hybrid power system by taking into account the characteristics of each power source. The main works of this paper are hybridization of alternate energy sources with FC systems using long and short storage strategies to build an autonomous system with pragmatic design, and a dynamic model proposed for a PV/FC/UC bank hybrid power generation system. A simulation model for the hybrid power system has been developed using Matlab/Simulink, SimPowerSystems and Matlab/Stateflow. The system performance under the different scenarios has been verified by carrying out simulation studies using a practical load demand profile, hybrid power management and control, and real weather data.

• Transactions on Electrical and Electronic Materials
• /
• v.18 no.2
• /
• pp.62-65
• /
• 2017

In this paper, three DC Block designs are presented which efficiently meet the need of modern-day compactsize wireless communication systems. As one of the important parts of a complete system design, the proposed microstrip-based DC block with coupled transmission lines efficiently attenuates unwanted frequencies that cause damage to the system. The compact-sized DC block structures are created by incorporating an extended coupled-line section with a radial stub, an enveloped coupled-line section, and using alternate up-down meandering techniques. The structures are analyzed for the L-Band using a high-resistive silicon substrate. At a resonating frequency of 1.575 GHz, the designed DC Block structures have a return loss better than -10 dB, an insertion loss of around -1 dB, and also possess wide pass-band characteristics.

• Wind and Structures
• /
• v.23 no.5
• /
• pp.421-447
• /
• 2016

Wind-induced and earthquake-induced excitations on tall structures can be effectively controlled by Tuned Liquid Damper (TLD). This work presents a numerical simulation procedure to study the performance of tuned liquid tank- structure system through ${\sigma}$-transformation based fluid-structure coupled solver. For this, a 'C' based computational code is developed. Structural equations are coupled with fluid equations in order to achieve the transfer of sloshing forces to structure for damping. Structural equations are solved by fourth order Runge-Kutta method while fluid equations are solved using finite difference based sigma transformed algorithm. Code is validated with previously published results. The minimum displacement of structure is observed when the resonance condition of the coupled system is satisfied through proper tuning of TLD. Since real-time excitations are random in nature, the performance study of TLD under random excitation is also carried out in which the Bretschneider spectrum is used to generate the random input wave.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.556-561
• /
• 2001

In order to investigate the vibration characteristics of fluid-structure interaction problem, we modeled two rectangular identical plates coupled with bounded fluid. The fixed boundary condition along the plate edges and an ideal fluid were assumed. An experimental modal analysis in order to extract the modal parameters of the system was performed. Finite element analysis was performed using ANSYS to verify modal parameters and analytic results were compared with experimental results. As a result, comparison of experiment and FEM showed good agreement and the transverse vibration modes, in-phase and out of-phase, were observed alternately in the fluid-coupled system. The effect of distance between two rectangular plates on the fluid-coupled natural frequency was investigated.

• Archives of Pharmacal Research
• /
• v.21 no.2
• /
• pp.212-216
• /
• 1998

A coupled achiral-chiral high-performance liquid chromatographic system has been developed for the determination of the enantiomers of salmeterol, S-(+)-salmeterol and R-(-)-salmeterol in urine. THe salmeterol was separated from the interfering components in urine and quantified on the silica column, and the enantiomeric composition was determined on a Sumichiral OA-4700 chiral stationary phase. The two columns were connected by a switching valve equipped with a silica precolumn. The two columns wer connected by a switching valve equipped with a silica precolumn. The precolumn was used to concentrate the salmeterol in the eluent from the achiral column before backflushing onto the chiral phase. The coupled system was validated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1034-1039
• /
• 2000

In turbo-machines operated at high speeds through gear speed increasers a precise coupled analysis of lateral and torsional vibrations is required to achieve highly reliable designs with low vibration and low noise levels, where the vibration coupling is due to the gear pair mesh stiffness. In this paper, applying the generalized coupled lateral-torsional finite element model of a gear pair element, has been analyzed a coupled lateral-torsional vibration of the prototype 800 RT turbo-chiller rotor-bearing system with a bull-pinion gear speed increaser. Results have shown that the coupled torsional natural frequencies have decreased due to the coupling effect of lateral vibration and particularly, the 2nd torsional natural frequency and its mode shape have had big changes. However, changes of lateral vibration characteristics have been noticed only at high lateral whirl natural frequencies above 15,000 rpm.

• Journal of computational fluids engineering
• /
• v.21 no.3
• /
• pp.89-97
• /
• 2016

In this study, direct code coupling, in which two codes share a single flow field, was conducted using 3-dimensional high resolution thermal hydraulics code, CUPID and 1-dimensional system analysis code, MARS. This approach provide the merit to use versatile capability of MARS for nuclear power plants and 3-dimensional T/H analysis capability of CUPID. Numerical Method to directly couple CUPID and MARS was described in this paper. The straight flow and manometer flow oscillation were calculated to verify conservation of coupled CUPID/MARS code in mass, momentum, and energy. This verification calculations indicates that the CUPID/MARS is coupled appropriately in numerical aspect and the coupled code can be applied to nuclear reactor thermal hydraulics after validation against integral transient experiments.