Analysis of pressure characteristics under laminar and turbulent flow states inside the pilot stage of a deflection flapper servo-valve: Mathematical modeling with CFD study and experimental validation

Saha, Bijan Krishna; Li, Songjing; Lv, Xinbei

doi:10.1016/j.cja.2019.11.016

Cited by 20 publications

(9 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A similar study by Yu et al [5] compared the experimental data to investigate the impact of nozzle geometry on the turbulence characteristics of fluid flow through the nozzles. It is also likely that the analytical model of the pressure attributes is authentic and beneficial to obtain an insight of the physical mechanism [27]. Moreover, the passive control device can control the base pressure, which result in an improvement in the base pressure and mitigating the base drag.…”

Section: Resultsmentioning

confidence: 99%

Determining the effect of nozzle groove on the fluid flow through viscous 2D planar fluid

Younis¹,

Ahmed²,

Hamdan³

et al. 2021

J Appl Eng Science

View full text Add to dashboard Cite

The study aims to determine the effect of nozzle groove on fluid flow through viscous 2D planar fluid. To fulfil the study’s aim, numerical method was adopted to introduce grooves of different dimensions from the nozzle exit. The study adopts SoldWork software was used to design nozzles and introduce groove shaped nozzles, each consisting of six different designs. The nozzle base model used in this study was similar to the one used in a previous study. The procedure was performed with different pressures (8, 10, and 12 bar) at the similar firefighting nozzle. The velocities contours were predicted based on the choice of nozzle section during the numerical stimulation. The results of present study demonstrated a new approach that can be used for increasing velocity at various types of modified nozzles through grooves at different pressures and locations. For grooves, dimensions 1×1 (mm) and location 15 mm at 8 bar, 10 bar and 12 bars showed no effect on velocity as it reduces velocity by increasing surface area. The velocity increases with increasing pressure in proportion relationship. This clearly explains that the groove has no effect on velocity as it increases due to increase in pressure. This is because the groove reduces the velocity by increasing surface area. The study concludes that use of groove increases velocity of water that further improves nozzles operation.

show abstract

Section: Resultsmentioning

confidence: 99%

Determining the effect of nozzle groove on the fluid flow through viscous 2D planar fluid

Younis¹,

Ahmed²,

Hamdan³

et al. 2021

J Appl Eng Science

View full text Add to dashboard Cite

show abstract

“…As u is contained in equations ( 6), (29), and (30), that is, u is coupled with T d . According to equations ( 6) and (12), the driving torque of the torque motor can be expressed as…”

Section: Temperature Mathematical Model Of Deflector Jet Servo Valvementioning

confidence: 99%

“…Hence, the research is mainly focused on the fundamental theory of the flow field of the deflector jet servo valve. Li 11 and Saha et al 12 considered the fluid in the receiving chamber as a piston that can move up and down independently, thus reducing the injection process to a collision between fluids. The piston model was verified by numerical simulation.…”

Section: Introductionmentioning

confidence: 99%

Temperature drift mechanism of deflector jet servo valve under temperature shock

Yan

Cai

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part I:

View full text Add to dashboard Cite

To study the mechanism of the deflector jet servo valve under temperature shock, a complete temperature theoretical model is proposed in this article. The temperature change affects the performance change of the torque motor by affecting the drift of the air gaps’ thickness, the permanent magnets’ reluctance, and the magnetomotive polarization force. Moreover, the temperature variation will act on the flow coefficient of the pilot stage, the size of the deflector, and jet pan, which influences the performance of the pilot stage hydraulic amplifier. Furthermore, the armature components, including the stiffness of the spring tube, the stiffness of the feedback rod, and the armature’s arm of force, are also related to the temperature variation. Comprehensively, considering the interaction influence of these factors, by analyzing the electromagnetic characteristics of the torque motor, the fluid mechanics’ characteristics of the pilot stage hydraulic amplifier, and the temperature performance of the armature assembly, the temperature drift model of deflector jet servo valve is constructed, which is represented as a ninth-order nonlinear equation. Based on the equation, the influence of temperature on the control precision of the servo valve is analyzed. The calculation results show that in the range of 20°C–250°C, the impact of temperature on the control accuracy will exceed 30%, the flow coefficient is the most significant affecting on the control accuracy, followed by the structural deformation of the pilot stage is the second factor affecting the temperature drift, and other factors have little effect. Comparison with the experimental results, the temperature drift model of the deflector jet servo valve can predict the control accuracy caused by temperature and provide a theoretical foundation for the optimization of the deflector jet servo valve.

show abstract

“…However, its structure is complex, and there are reliability problems such as self-excited oscillation. 8–12 In recent years, servo control and proportional control technologies have begun to merge with each other. As a result, the so-called servo-proportional valve has emerged, which is characterized using a high-performance linear electro-mechanical converter (LEMC) to directly drive the spool, and spool position is measured by a spool displacement sensor to form closed-loop control.…”

Section: Introductionmentioning

confidence: 99%

Novel modulation approach of flat force–displacement characteristic of linear electro-mechanical converter for electro-hydraulic servo-proportional valve

Meng

Heng

Sheng

2022

Proceedings of the Institution of Mechanical Engineers, Part I:

View full text Add to dashboard Cite

Flat force–displacement characteristic has crucial influence on the performance of linear electro-mechanical converter of electro-hydraulic servo-proportional valves. The commercial proportional solenoids obtain such features by welding a non-magnetic separator ring, which is complicated and time-consuming. This article presents a novel modulation approach to obtain the flat force–displacement characteristic of linear electro-mechanical converter by constructing a by-pass air gap. Taking an existing linear force motor as an example, the force–displacement characteristic curves of the linear force motor with by-pass air gap and without by-pass air gap are both studied using magnetic circuit analysis and finite element method under different excitation currents. Based on the finite element method simulated data, the response surface method is used to perform the experiment design for structure parameters of linear force motor with by-pass air gap, and the quadratic fitting equations are obtained for further optimization. To balance conflicted design objectives such as linearity, mean value of output force and power-to-weight ratio, the structural parameters of the linear force motor with by-pass air gap are optimized using a multi-objective optimization algorithm based on particle swarm. Prototypes of linear force motor with by-pass air gap and without by-pass air gap are both manufactured, and a special test rig is built. The static and dynamic experimental results are consistent with the theoretical analysis. The former proves that the linear force motor with by-pass air gap can obtain a nearly flat force–displacement curve with reasonable parameter optimization and also improve output force, and the latter reveals that a linear electro-mechanical converter with flat–displacement characteristic has better working stability over common ones. The proposed modulation approach provides a new approach for the design of flat force–displacement characteristic of linear electro-mechanical converter.

show abstract

Analysis of pressure characteristics under laminar and turbulent flow states inside the pilot stage of a deflection flapper servo-valve: Mathematical modeling with CFD study and experimental validation

Cited by 20 publications

References 13 publications

Determining the effect of nozzle groove on the fluid flow through viscous 2D planar fluid

Determining the effect of nozzle groove on the fluid flow through viscous 2D planar fluid

Temperature drift mechanism of deflector jet servo valve under temperature shock

Novel modulation approach of flat force–displacement characteristic of linear electro-mechanical converter for electro-hydraulic servo-proportional valve

Contact Info

Product

Resources

About