Stabilization of pilot valve system using linear flow resistance

Peng, Jiehong; Youn, Chongho; Takeuchi, Taku; Kagawa, Toshiharu

doi:10.1177/1687814017719421

Cited by 5 publications

(3 citation statements)

References 22 publications

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“…Oscillation problem has also been identified in pilot tube of the downstream pipeline. Some factors were established that could cause oscillation, such as choking flow, dead bands, and self-excitation of the moving component in valve [11]. To solve oscillation problem, a resistance to flow that is linear in characteristic was introduced through orifice and installation of porous material.…”

Section: Literature Reviewmentioning

confidence: 99%

Stability Analysis of Globe Valve Using Classical Techniques

Olugbenga¹,

Olajide²,

Adesola³

2021

JESR

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The importance of globe valve in fluid handling and control cannot be overemphasized. It is useful in oil and gas applications. If globe valve is not properly modelled, its primary purpose of regulation of fluid flow may be defeated. In this work, model of globe valve is developed from basic mechanical principles. The resulting model is a second order system whose response to a step input signal gives no overshoot. Further stability analysis with bode plot, Nyquist plot and root locus plot give a stable system indicating that the developed globe valve model is suitable for relevant areas of application.

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Section: Literature Reviewmentioning

confidence: 99%

Stability Analysis of Globe Valve Using Classical Techniques

Olugbenga¹,

Olajide²,

Adesola³

2021

JESR

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show abstract

“…A common feature for the instability to establish is that the valve’s obstructing element and the fluid system, when set into oscillatory motion, couple in a way that the resulting dynamic forces provoke the motion of the valve’s element. Therefore, a continuous supply of fluid energy to the structure is maintained leading to valve instability such as in the cases of Wang et al, 10 Allison et al, 11 Peng et al, 12 El Bouzidi et al, 13 Ma et al 14 and Jia et al 15…”

Section: Introductionmentioning

confidence: 99%

“…A common feature for the instability to establish is that the valve's obstructing element and the fluid system, when set into oscillatory motion, couple in a way that the resulting dynamic forces provoke the motion of the valve's element. Therefore, a continuous supply of fluid energy to the structure is maintained leading to valve instability such as in the cases of Wang et al, 10 Allison et al, 11 Peng et al, 12 El Bouzidi et al, 13 Ma et al 14 and Jia et al 15 According to the mentioned studies, (TIV) vibration is a serious problem since it can risk the safe operation of the power plant. In consequence, the first aim of this study is to develop a theoretical model that can explain the excitation mechanism and simulate the seal's periodic vibrations while considering the dynamic seal characteristics, the unsteady nonlinear hydraulic losses, and the power plant relevant data.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear dynamic performance of the turbine inlet valves in hydroelectric power plants

Awad

Parrondo

2023

Advances in Mechanical Engineering

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In practice, vibrations in the turbine inlet valves can develop flow rate and pressure fluctuations in the penstocks of the hydropower plants that can risk the safe operation of the power plant. Accordingly, this study has two aims: the first aim is to explain and simulate the valve’s periodic vibrations while considering the power plant’s relevant physical and geometrical parameters. The second aim is to provide recommendations to improve the dynamic stability of the valve’s vibrations. The theoretical model developed to explain the phenomenon comprises the nonlinear unsteady energy equations representing the fluid flow at the pipelines, the continuity equation modelling fluid flow through different junctions, and the valve’s seal equation of motion to compute the valve’s vibrations. The system governing equations are solved nonlinearly using the MATLAB toolbox SIMULINK. The study demonstrated that the origin of the valve’s vibrations is the leakage of the valve’s service seal. The presented model results exhibited that the unstable valve vibrations (of increasing amplitudes) are more prone to occur at higher input reservoir energy levels. Also, installing a valve that can be closed to a certain degree at the pilot pipeline can enhance the dynamic stability of the valve’s vibrations.

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Variable viscous flow resistance based on rotational inertia

Shen

2023

Physics of Fluids

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Viscous flow resistance is dominated by viscous friction between fluid and wall. The flow resistance characteristic curve (i.e., the relationship curve between pressure drop and flow rates, represented as the Δp–Q curve) depends on some inherent characteristic variables, such as structural size, fluid viscosity, density, and temperature. Usually, to change the Δp–Q curve, these inherent characteristic variables must be changed. This paper proposes a new design of variable viscous flow resistance. The new design uses two disks to construct a slit flow channel, and rotate one of the disks to drive the fluid in the slit flow channel to form a rotational inertia effect. Therefore, by changing the rotating speed of the disk, the rotational inertia effect can be changed, thereby achieving the purpose of changing the Δp–Q curve. This paper derives a theoretical model for the pressure distribution of the rotating slit flow field and conducted experimental verification. It was found that the rotational inertia gradient and viscous gradient terms play major roles in governing the radial pressure gradient. The sum of the other two inertial gradient terms accounts for a maximum of about 1.58% of the total pressure gradient. There is a coupling relationship between circumferential velocity, radial velocity, and flow rates. An increase in Q can increase the rotational inertial gradient term by up to 24.9%. The rotating disk causes additional radial velocity and thus weakens the viscous gradient term by at least 16.41%.

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Stabilization of pilot valve system using linear flow resistance

Cited by 5 publications

References 22 publications

Stability Analysis of Globe Valve Using Classical Techniques

Stability Analysis of Globe Valve Using Classical Techniques

Nonlinear dynamic performance of the turbine inlet valves in hydroelectric power plants

Variable viscous flow resistance based on rotational inertia

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