• Journal of Advanced Marine Engineering and Technology
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• v.23 no.1
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• pp.69-78
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• 1999

In this study a new pattern of pressure control of hydraulic cylinder using high speed On-Off solenoid valve in the electro-hydraulic system has been suggested. The control valve is 3-way high speed On-Off solenoid valve which is operated by PWM(Pulse Width Modulation)control signal. The high speed On-Off solenoid valve has a tendency to induce severe pressure fluctuation in the hydraulic actuator so it has not been used for the purpose of closed loop control with direct pres-sure feedback. In this study closed loop control with direct pressure feedback is enabled by using a digital filter which has linear minimum mean square filter algorithm. Through some experiments it is confirmed that stable pressure control can be realized by the proposed control technique.

• Journal of the Korea Convergence Society
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• v.10 no.1
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• pp.149-154
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• 2019

High pressure valve tester used in industrial fields precise measurement gives inconvenience in precise measurement due to manually regulated pressures. In order to improve this inconvenience, the high pressure valve tester was designed by using CATIA and structural analysis of the designed high pressure valve tester was conducted and water leaking, total deformation, strain and stress were obtained by applying ANSYS. These results will be provided to develop new concepts of high pressure valve tester as initial data.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.11 no.1
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• pp.1-10
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• 1982

The water-hammer phenomena caused by pump power failure are analysed by digital computer. Asan cool ins water pipe system has been chosen as a model. It is Shown that after power failure the pressure at the pump outlet drops sharply, and to prevent reverse flow, either butterfly valve or check valve can be used. After the valve closure, pressure oscillates behind the valve. To weaken the pressure wave, it is recommended to install a servo-operated valve in a bypass Line around the pamp and the check valve.

• Journal of Power System Engineering
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• v.12 no.2
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• pp.62-70
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• 2008

The paper made a description of the method for numerical analysis and modeling of a proportional pressure control valve by bondgraph. The valve is a three port pressure regulator valve, consists of two subsystems; a proportional solenoid and a spool assembly. A purpose of this study is to analysis the dynamic characteristics of the valve using bondgraph method and to verified results that each of parameters has an effect on modeling. It considered the effect which the presence of solenoid, flow coefficient and non-linearity of resistance causes in the valve modeling. In particular, it is analyzed the effect that the solenoid interacted with modeling results and characteristics of the nonlinear resistance through orifice on the supply and discharge side of valve. Thus this paper described method to present nonlinear characteristics by bondgraph modeling method, so that we could know easily result that each parameters has an effect on the modeling.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.294-298
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• 2001

Satellite propulsion system is employed for orbit transfer, orbit correction, and attitude control. The monopropellant feeding system in the low-earth-orbit satellite blowdowns fuel to the thrust chamber. The thrust produced by the thruster depends on fuel amount flowed into the combustion chamber. If the thruster valve be given on-off signal from on-board commander in the satellite, valve will be opened or closed. When the thrusters fire fuel flows through opened thruster valve. Instantaneous stoppage of flow in according to valve actuation produces transient pressure due to pressure wave. This paper describes transient pressure predictions of the KOMPSAT2 propulsion system resulting from latching valve and thrust control valve operations. The time-dependent set of the fluid mass and momentum equations are calculated by Method of Characteristics (MOC).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.10
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• pp.884-888
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• 2007

It is necessary to evaluate periodically the performance of the AOV(air-operated valve) which is used for controlling flow and pressure in nuclear power plant. The required thrust for actuating valve and available thrust of actuator are calculated with conditions of flow through a valve in this study and operating performance is analyzed through comparing two thrusts. In general, differential pressure is increased according to increase the flow rate and differential pressure affects the required thrust of valve. We found the fact that it is possible not to close the valve perfectly because required thrust becomes bigger than available thrust of actuator.

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.865-871
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• 2018

The 3-way valve have been used as a valve for opening and closing the valve by the flow control in the pressure system of the cryogenic and high pressure environment. In this paper, numerical analysis and experimental study on fracture nipple of 3-way ultra high pressure valve applied to space launch vehicle was carried out. We have developed a 3-way valve numerical simulation modeler of cryogenic environment using commercial software ANSYS 18.2. As results of numerical analysis, optimum nipple condition was derived. In addition, a 3-way valve prototype was fabricated and the fracture test was performed and compared with the numerical analysis results.

• Journal of Drive and Control
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• v.18 no.3
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• pp.23-29
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• 2021

Hydrogen energy is the clean energy source of the future. Ultra-high-pressure hydrogen is used in hydrogen stations, with its parts being developed. On the other hand, ultra-high-pressure ball valve, which is one of its parts, depends on overseas, with the level of domestic research on this being only about 10% of advanced technology research on this abroad. In this study, the shape of an ultra-high-pressure ball valve for a hydrogen station was designed to improve its structural strength. The valve body was designed according to distance between both processed body holes along inlet and outlet ports. The designed vale body was then analyzed using ANSYS to check whether points with stress were concentrated. In addition, the valve with improved body was analyzed to confirm that the valve satisfied the design condition.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1576-1577
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• 2007

As a intelligent valve piezoelectric valve is to applied to various fields of application. Piezoelectric valves have fast response time and good linearity for pressure control but its hysteresis displacement by its stack actuator influences on pressure control in electro-hydraulic braking. Solenoid valves are traditional element to control hydraulic pressure but this paper proposes piezoelectric valve for brake pressure control with hysteresis compensation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.121-127
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• 2007

Direct acting pressure relief valve applicable to propellant tank of launch vehicle is modeled in this study The flow resistance of the partially opened valve is modeled as a function of the distance of the valve stem from the resting position. The position of the valve varies transiently as a function of its mass, the spring force, sliding friction, and the pressure differential. Choking at valve throat and compressibility are considered for the analysis. This study presents systematic analysis method for pressure relief valve applicable to propellant tank of liquid rocket. The results shows transient flow resistance caused by stem motion and the importance of choking at valve throat for pressure relief valve design.