• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.3
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• pp.239-248
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• 2017

According to the structure, solenoid valve can be categorized as spool valve or poppet valve. While various research on spool valve which has simple structure and fine susceptibility to contamination has been conducted, poppet valve which has less susceptibility to contamination and advantage in a long time operation still need much research because of its complicated structure. In order to design the poppet valve, various parameters such as the diameter of the poppet, the angle of the poppet, the diameter of the disk, the spring stiffness, the spring preload and flow path structure should be considered. Conventional studies on poppet valve usually take only one design parameters and did not much focused on the effect of the parameters on flow characteristics. In this paper, the change of the flow characteristics according to the design parameters of the poppet valve for 3/2Way solenoid valve is analyzed. The previous studies and the results of initial model analysis was referred for the selection of the design parameters. The effects of design parameters on maximum pressure, minimum pressure, and pressure drop was examined using analysis of means(ANOM).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.812-818
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• 2009

A MOV(Main Oxidizer shutoff Valve) controls the flow rate of liquid oxygen into the rocket combustor by opening and shutting operations piloted by a pneumatic force. In order to improve the effective design for sealing parts of poppet and piston assemblies, the poppet assembly has been designed to be just contacted with the piston assembly. However, to avoid a gap at the poppet/piston contact surface and to evaluate the MOV operating performance, an analyze on the force balance during the closing motion have been performed. For the accuracy of the analysis, the friction forces and the hydraulic forces have been respectively obtained by experiments and CFD analysis. Through the analysis, some important design parameters such as the spring constant, poppet friction and orifice size in the force balance have been introduced and the required operation performance of the MOV has been proved feasible.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.6
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• pp.113-119
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• 2013

A main oxidizer shut-off valve (MOV) controls the supply of cryogenic liquid oxygen to the combustion chamber of liquid rocket engines by on/off operations. The main subjects to be introduced are not only the valve transient response during valve on/off procedures but also the characteristics of pneumatic and seat/poppet parts as core technologies in the development of the MOV, which is expected to be adopted for the Korea Space Launch Vehicle II. It is shown that the analytical prediction of the transient valve travel is in good agreement with experimental results. Friction and elastic forces on the valve moving part are quantitatively evaluated by structural analysis.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.84-90
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• 2012

Fuel shutoff valve of a combustion chamber controls propellant mass flowrate of a rocket engine, by using pilot pressure and spring force. The developing fuel shutoff valve can be self sustained even though pilot pressure is removed in an actuator. Therefore, it is necessary to analyze the characteristics of the forces with respect to the opening and closing of the valve in order to evaluate its performance. In light of this, the valve has been designed to adjust the control pressure for the opening of the poppet and to determine the working fluid pressure at which the valve starts to close. This paper also has been predicted flow coefficient of the valve by Fluent(ver. 12.0) CFD analysis. Various results from the prediction and the analysis have been compared with experiments.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.160-166
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• 2014

The shutoff valve of a Liquid Rocket Engines (LRE) controls the flow of propellant between turbo-pump and combustion devices of LRE using pilot pressure and spring force. The shutoff valve is closed when the pilot pressure is removed from the diaphragm type actuator. During designing process of life cycle is when should be analyzed according to the characteristics of forces with respect to the opening and closing of diaphragm actuator. A valve has been designed to adjust the control pressure which is required to open a poppet and to determine the working fluid pressure at which a valve starts to close. During flow capacity test under room temperature as a part of life cycle tests, the leakage in diaphragm was occurred due to the leakage of sheet welding sections. The operating cycle of the diaphragm type actuator is about 61 times with 22 MPa of pilot pressure.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.4
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• pp.1-9
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• 2010

Fuel shutoff valve of a gas generator controls propellant mass flowrate of a rocket engine, by using pilot pressure and spring force. The developing fuel shutoff valve can be self sustained even though pilot pressure is removed in an actuator. Therefore, it is necessary to analyze the characteristics of the forces with respect to the opening and closing of the valve in order to evaluate its performance. In light of this, the valve has been designed to adjust the control pressure for the opening of the poppet and to determine the working fluid pressure at which the valve starts to close. This paper also has been designed dynamic model using the AMESim and predicted flow coefficient of the valve by Fluent CFD analysis. Various results from the prediction and the analysis have been compared with experiments. Finally, dynamic characteristics of the valve have been verified with experimental results.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.108-117
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• 2013

The oxidizer shutoff valve of a gas generator controls the mass flow rate of the propellant of a rocket engine using pilot pressure and spring the force of the valve. The developing oxidizer shutoff valve can be shut off if the pilot pressure is removed from the actuator. Therefore, force balancing is necessary to analyze the characteristics of the forces with respect to the opening and closing of the valve in order to evaluate its performance. In light of this, the valve has been designed to adjust the control pressure required to open the poppet and to determine the working fluid pressure at which the valve starts to close. Under cryogenic flow test as a tests level of C.R.T(Control Random Test), the chattering phenomena occurred due to much leakage of a metal seat section. The pressure for chattering of the oxidizer valve is predicted at about 11 bar using force balancing analysis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.11
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• pp.989-997
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• 2017

We study opening transient responses of a self-sustainable poppet valve, which is usually used for the main oxidizer shut-off valve of liquid rocket engines. In order to perform numerical analysis, a pneumatic supply system was simulated as an orifice with a diameter of 3.2 mm and the equations of motion of valve moving part were derived. For the validation of the study, a comparison of numerical predictions and experimental results has been done. As one of the practical applications of this study, the employment of an orifice in a high pneumatic pressure has been presented to control the valve opening time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.801-807
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• 2020

Opening characteristics of a main oxidizer shut-off valve at different valve inlet pressures have been experimentally investigated. The pilot pressure at the moment of the valve opening increases linearly with increasing the valve inlet pressure and the increased pilot pressure reduces the valve travel time. As the pilot pressure increases at the moment of valve opening, the time to start opening the valve is delayed resulting in increasing the valve opening time. With the increment of the valve inlet pressure, the valve opening time is mainly determined by the time required for the pilot pressure to start opening the valve. Therefore the design of a pilot gas supply system can readily control the valve inlet pressure at the valve opening as well as the amount of oxidizer supplied to a combustion chamber during the engine startup.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.9
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• pp.717-724
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• 2020

We study the closing characteristics of a self-sustainable poppet valve which serves as a main oxidizer shut-off valve for liquid rocket engines. Numerical analysis for predicting closing transient responses are presented and the calculated results have been verified by a comparison with experimental data. The effective area of a pilot gas discharge system and the pressure distribution of passage flow around the valve moving part are shown to be main parameters in determining the closing characteristics for dry and cryogenic conditions, respectively. Moreover, it is presented that the passage flow pressure at the valve closing moment as well as the valve closing velocity can be effectively adjusted by the appropriate employment of the pilot gas.