• Proceedings of the KSME Conference
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• 2002.08a
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• pp.321-324
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• 2002

Hydraulic valve control the pressure and the How of fluid by the hydraulic oil transfered from pump but the ER fluid consists of solid particles of micrometer in size and insulating oil so in the general hydraulic valve. We invented ER-Valve using ER fluid as working fluid. The ER fluid, working fluid of ER-Valve is a functional fluid to represent the feature of fluid according to strength of electric field. In this research we made our own 4 types of plate type ER-Valve which has same surface but different width and length and then we conducted performance test. We measured flow rate and pressure drop of fluid which is flowing in the ER-Valve according to the electric field strength to conduct this test. We modeling ER-Valve relating to ER-Valve system and yield shear stress according to the strength of electric field. We used the pressure drop according to the strength of electric field by differential pressure gauge in the our own made ER-Valve. This test reviewed experimental the special changes of ER-Fluid in the steady flow condition.

• International Journal of Fluid Machinery and Systems
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• v.3 no.1
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• pp.58-66
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• 2010

A steam control valve is used to control the flow from the steam generator to the steam turbine in thermal and nuclear power plants. During startup and shutdown of the plant, the steam control valve is operated under a partial flow conditions. In such conditions, the valve opening is small and the pressure deference across the valve is large. As a result, the flow downstream of the valve is composed of separated unsteady transonic jets. Such flow patterns often cause undesirable large unsteady fluid force on the valve head and downstream pipe system. In the present study, various flow patterns are investigated in order to understand the characteristics of the unsteady flow around the valve. Experiments are carried out with simplified two-dimensional valve models. Two-dimensional unsteady flow simulations are conducted in order to understand the experimental results in detail. Scale effects on the flow characteristics are also examined. Results show three types of oscillating flow pattern and three types of static flow patterns.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.6
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• pp.29-35
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• 2003

In this research 4 plate type ER-Valves which have same surface but different width and length are designed and an experimental apparatus is constructed. With this experimental apparatus, flow rate and pressure drop of ER fluid flowing in ER-valves are measured with varying electric field strength of ER-valve, and relation between valve types and pressure drop is also experimented. ER fluid is made silicon oil mixed with 40wt% starch having hydrous particles. If we allow the same electric field in the ER-Valve, we came to how that the pressure drop is effected by the electrode length and electrode width. When the strength of the electric field increased, the pressure drop happened big and the flow rate decreased.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.157-158
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• 2004

To investigate the effects of the upstream flow conditions on the opening performance of the swing check valve, the tests were performed at various conditions of the disturbance type and distance from the tested check valves. The results show that the upstream flow disturbances due to elbow and globe valve at $2{\sim}10$ diameters upstream of the check valve produced minor effects on the check valve performance compared to the uniform flow condition. However, more detail analysis and additional testing with the other disturbance source, such as orifice with a large number of holes, are needed to refine and confirm the present results.

• 연구논문집
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• s.30
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• pp.93-99
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• 2000

Electro-Rheological(ER) fluids change their apparent viscosity according to the electric field strength. The electrical and rheological properties of zeolite based the ER fluids were reported. The electric field dependent yield stress are obtained from experimental investigation on the Bingham property of the ER fluid. Using ER fluids, it is possible to directly interface between electric drop and flow rate of the ER fluid was hydraulic control valve measured under application of an electric field. The purpose of the present study is pressure drop measurement of an ER valve by using strain gage. The performance characteristics of the valve system are evalusted in terms of pressrue fixed with respect to the intensity of employed electric fields and flow rates. As a result, it is esperimentally confirmed that pressure control valve using ER fluids applicable to use in hydraulic power systems.

• Tribology and Lubricants
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• v.29 no.5
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• pp.291-297
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• 2013

Hydraulic directional control valves actuated by solenoid are used to control emergency steering in general or hybrid electric commercial vehicles. In this study, a new lightweight hydraulic directional control valve was designed by flow and structural simulation, and was fabricated; the basic operation, pressure differentials, and inner leakage flow were evaluated experimentally. In the results, the new model showed comparable performance with an existing imported valve. New valve was 80% the weight of the existing valve and had few components. Installing this valve on a truck body is easier because of its compactness and small size.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.52-64
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• 1996

This paper presents an active position control of a single-rod cylinder system featuring an electrorheological(ER) fluid-based valve. The ER fluid consisting of silicone oil and chemically treated particles is firstly composed and its Bingham property is tested as a function of imposed electric field. A multi-channel plate type of ER valve is then designed and manufactured on the basis of the field-dependent Bingham model. Performance test of the ER valve is undertaken by evaluating pressure drop with respect to the number of electrode as well as the intensity of the electric field. Subsequently, the ER valve-cylinder system is constructed and its governing equation of motion is derived. A neural control scheme for position control of the cylinder is formulated by incorporating proportional-plus-derivative(PD) controller and implemented. Experimental results of both regulating and tracking control responses are presented in order to demonstrate the efficacy of the proposed ER valve-cylinder control system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1123-1126
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• 2003

In this research 4 plate type ER-Valves which have same surface but different width and length are designed and an experimental apparatus is constructed. With this experimental apparatus, flow rate and pressure drop of ER fluid flowing in ER-Valve are measured by varying electric field strength of ER-valve, and relation between valve types and pressure drop is also experimented. ER fluid is made silicon oil mixed with 40wt% starch having hydrous particles. The pressure drop according to the strength of electric field by differential pressure gauge in the present ER-Valve was used. This test reviewed experiment for the special changes of ER fluids in the steady flow condition.

• Journal of Magnetics
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• v.18 no.4
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• pp.466-472
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• 2013

This paper presents a new design of the hybrid magnet engine valve actuator using the shorted turn for enhanced dynamic performance. The quick response of coil electric current is the most important factor that determines the opening and closing performance of the hybrid magnet engine valve. The conventional hybrid magnet engine valve actuator, however, has a delayed initial electric current rising when it is driven by voltage control because of the coil inductance which is a typical characteristic of an electromagnetic coil. A shorted turn is newly placed into the upper yoke of the hybrid magnet engine valve actuator to reduce coil inductance and thus, to hasten the initial electric current rising. We performed a dynamic finite element analysis to demonstrate the improvement of the dynamic characteristics of the hybrid magnet engine valve actuator due to the shorted turn.

• Journal of Drive and Control
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• v.16 no.1
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• pp.29-35
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• 2019

The control performance of hydraulic systems is basically influenced by the performance of electrohydraulic servo valve incorporated in a hydraulic control system. In this study, a control design was proposed to improve the control performance of a servo valve with a non-contact eddy current type position sensor. A mathematical model for the valve was obtained through an experimental identification process. A PI-D control together with a feedforward (FF) control was applied to the valve. To further improve the dynamic response of the servo valve, an input shaping filter (ISF) was incorporated into the valve control system. Finally, the effectiveness of the proposed control system was verified experimentally.