• Title/Summary/Keyword: Constant pressure drop valve

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A Study on Stability Improvement of Fuel Metering Unit for Air Breathing Engine (공기흡입식 추진기관용 연료조절밸브 시스템 안정성 향상에 관한 연구)

  • 이도윤;박종승;최현영;구자용
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.9
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    • pp.76-81
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    • 2006
  • This paper deals with a fuel metering unit (referred to as FMU) for air breathing engine. The proposed FMU consists of a constant pressure drop valve and a metering valve, both of which are controlled by servovalve. Linear analysis derived from a nonlinear mathematical model of FMU is carried out to find major parameters on the system performance. Numerical results using established model of FMU were in good agreement with the experimental results. It is also shown that the system stability is improved by reducing the constant pressure drop at metering valve and applying the triangular orifice to constant-pressure-drop valve through the simulation and experiments.

A Study on the Development of Fuel Metering Unit for Air Breathing Engine (공기흡입식 추진기관용 연료조절밸브시스템 개발에 관한 연구)

  • Lee, Do-Yun;Choi, Hyun-Young;Park, Jong-Seung;Koo, Ja-Yoeng
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.4 s.23
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    • pp.152-158
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    • 2005
  • In this paper, we have proposed a fuel metering unit of ai breathing engine. The proposed valve system consists of a constant pressure drop valve and a metering valve, which are controlled by servovalve. We carried out nonlinear and linear analysis, computer simulation and experimentation to find effects of some factors on system performance. Analysis and experimental results show a good agreement. It is also shown that the system stability is affected by pressure drop of metering valve and inlet pressure of injectors.

A Study on a Direct-Type Proportional Flow Control Valve Utilizing Flowforces (유체력을 이용한 직동식 비례 유량 조절 밸브에 관한 연구)

  • 배상기;현장환;이정오
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.4
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    • pp.68-75
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    • 1998
  • A one-stage direction and flow control valve was studied theoretically and experimentally. A direction and flow control valve maintains a constant flow rate by changing the spool-orifice area under the variation of valve pressure drop, since the spool-orifice area is varied by the action of flowforces on the spool. A direction and flow control valve has the advantage of simple and low-cost structure compared to a conventional flow control valve utilizing a pressure regulating spool which regulates the pressure drop caused by flow through the metering orifice. The static and dynamic characteristics of a one-stage direction and flow control valve was analyzed. Experimental results on the flow control characteristics of the manufactured valve show satisfactory agreement with simulation results.

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A Study on the Design and Modeling of PWM Fuel Metering Unit for Miniature Turbo Engines (초소형 터보엔진용 PWM 연료조절장치의 설계 및 모델링에 관한 연구)

  • Joo Sang-Hyun;Choi Ho-Jin;Park Jong-Seung;Lim Jin-Shik
    • Journal of the Korean Society of Propulsion Engineers
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    • v.10 no.2
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    • pp.95-101
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    • 2006
  • A fuel metering unit using PWM(Pulse Width Modulated) solenoid valve has some advantages such as low cost, small size and simple structure. The mathematical model and its experimental rig of the fuel metering unit using PWM solenoid valve and CPDV(Constant Pressure Drop Valve) for miniature turbo engines were constructed. As the results of simulation, some major parameters which have dominant effects on the performance were found. And the experimental results verified the validity of established model by showing the good agreement with the numerical simulation results. Hence, this system modeling could be used effectively in the actual development of a PWM fuel control system.

A Study on the Design of Liquid Flow Control Valves for the Pants and Ships(II) (플랜트 및 선박의 액체용 우량제어밸브 설계에 관한 연구(II))

  • 최순호;배윤영;김태한;한기남;주경인
    • Journal of Advanced Marine Engineering and Technology
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    • v.19 no.2
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    • pp.1-9
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    • 1995
  • The processing paper has devoted to the theory of the flow equations, the basic derivative procedure, the meaning of a valve flow coefficient $C_v$, the valve Reynolds R$R_{ev}$ and its application for liquid control valves, which applicable under the condition of a non-critical flow and the case of piping geometry factor $F_p$=1.0. However there is no information on the effects of fittings, a critical flow and the flow resistance coefficient of a valve equivalent to that of pipe which is conveniently used in the piping design. Since the piping systems of plants or ships generally contain various fittings such as expanders and reducers due to different size between pipes and valves and there may occur a critical flow, that a mass flowrate is maintained to be constant, due to the pressure drop in a piping when a liquid is initially maintainder ar a saturated temperature or at nearby corresponding to upstream pressure, system designer should have a knowledge of the effect to flow due to fittings and the critical flow phenomenon of a liquid. This study is performed to inform system designers with the critical flow phenomenon of a liquid, a valve resistance coefficient, a valve geometry factor and their applications.

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Development of a Flow Rate Sensor Using 2-way Cartridge Valve (2-유로 카트리지 밸브를 이용한 유압용 유량 센서의 개발)

  • 홍예선;이정오
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.9
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    • pp.2381-2389
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    • 1993
  • In this paper the design and test results of a dynamic flow rate sensor was reported. This sensor comprises an 2-way cartridge valve as standard hydraulic component and a displacement sensor. Its working principle bases on the linear relationship between the flow rate and the piston displacement of 2-way cartridge valves under constant pressure drop. This principle is well known, however it is not easy to develop a flow rate sensor with the measurement range of 300 1/min, pressure loss of less than 8 bar at 300 1/min, maximum linearity error of less than $\pm$1% and the maximum rising time of 10 ms. This paper describes the design procedure of the flow rate sensor, the improvement procedure of static performance and test method and results of dynamic performance.

Numerical Simulation of The Pressure-Flow Control Characteristics of Shunt Valves Used to Treat Patients with Hydrocephalus (수두층 치료용 션트밸브의 압력-유량 제어특성 수치해석)

  • 장종윤;이종선;서창민
    • Journal of Biomedical Engineering Research
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    • v.22 no.5
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    • pp.403-412
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    • 2001
  • The Present study analyzed the pressure-flow characteristics of a Korean shunt valve. Changes in the characteristic currie depending on the design parameters were also investigated. The Korean shunt valve used in the present study was constant pressure type and our analyses were validated through experiments. We applied fluid-structure interaction to solve the flow dynamic Problem because the small diaphragm in the valve was made from flexible silicone elastomers. Considering the material nonlinearity of the hyper-elastic material. the Mooney-Rivlin approximation was employed. The results of the numerical analyses were close to the experimental results The major Pressure drop was observed to happen in the small diaphragm. The slope of the pressure-flow characteristic curve was computed to be 0.37mm$H_2O$.hr/cc, which was similar to the average value of commercial shunt valves. 0.40mm$H_2O$.hr/cc. Therefore. our valves analyzed in the Present study showed a Proper Pressure control characteristics of the constant pressure type shunt valves. The opening pressure could be controlled by adjusting the amount of predeflection of the valve diaphragm. In order to obtain opening pressures of 25mm$H_2O$ and 80mm$H_2O$, respectively, and the required predeflection was found to be 10.2$\mu$m and 35.3$\mu$m. The flow orifice size was found to be within 10$\mu$m during valve operation Therefore, Precision design and manufacturing techniques are necessary for successful operations of the shunt valve. The study indicated the amount of predeflection as well as the magnitude of corner rounding of the diaphragm edge are important design parameters to influence the slope of the pressure-flow characteristic curve.

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Unsteady Flow Analysis of Liquid Hydrazine Propellant for the Design Parameter Derivation of Satellite Propulsion System (인공위성 추진기관 설계변수 도출을 위한 Hydrazine 액체 추진제의 비정상 유동해석)

  • Choi, Jin-Chul;Kim, Jeong-Soo
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.497-501
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    • 2000
  • One of the way to derive design parameters of the fuel feeding system in satellite is to analyze unsteady flow of liquid propellant (hydrazine) in the propulsion system. During steady thruster firing the flow rate is constant: if a thruster valve is abruptly shut down among a sets of thrusters, pressure spikes much higher than the initial tank pressure occur. This renders the fuel flow unsteady, and the fluid pressure and flow rate to oscillate. If the pressure spikes are high enough, there are possibilities that propellant explosively decomposes, thruster valves are damaged, and adiabatic detonation of the hydrazine propellant is potentially incurred. Reflected shockwaves could also affect the calibration and operation of the pressure transducers. These necessitate the analysis of unsteady flow in the propulsion system design, and the calculation results obtained through some governing parameter variation are presented in this work.

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Design of a Hydrodynamic Mock Circulation System For Prosthetic Heart Valve Testing (인공심장 판막의 수력학적 특성)

  • Wetering, Jan E.v.d.;Suh, Soo-W.;Kim, Gi-J.;Chong, Chan-I.;Kim, Hee-C.;Kim, In-Y.;Min, Byoung-G.
    • Proceedings of the KOSOMBE Conference
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    • v.1993 no.05
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    • pp.146-151
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    • 1993
  • A new hydrodynamic mock circulation system was developed, which can test prosthetic heart valves of various sizes in order to obtain valve parameters, such as pressure drop, regurgitation and valve performance index with a high reproducibility. High reproducibility can be obtained only under equal testing conditions, i.e., the compliance, resistance and inertance of the mock circulation system must be constant parameter estimation using actual pressure and flow data was applied to calculate these systemic variables in order to adjust them to create the necessary equal testing conditions.

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A STUDY ON THE PRESSURE BEHAVIOR INSIDE PROPELLANT LINE OF SATELLITE (인공위성 연료배관의 유압특성 연구)

  • Choi, Jin-Chul;Kim, Jeong-Soo
    • Journal of Astronomy and Space Sciences
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    • v.19 no.3
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    • pp.207-214
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    • 2002
  • One of the way to derive design parameters of the fuel feeding system in satellite propulsion system is to analyze unsteady flow of liquid propellant (hydrazine). During steady thruster firing the flow rate is constant: if a thruster valve is abruptly shut down among a set of thrusters, pressure spikes much higher than the initial tank pressure occur. This renders the fuel flow unsteady, and the fluid pressure and flow rate to oscillate. If the pressure spikes are high enough, there are possibilities that propellant explosively decomposes, thruster valves we damaged, and adiabatic detonation of the hydrazine propellant is potentially incurred. Reflected shockwaves could also affect the calibration and operation of the pressure transducers. These necessitate the analysis of unsteady flow in the propulsion system design, and pressure behavior inside the propellant line obtained through some governing parameter variation is presented in this work.