Impact of Flow Force to the Constant Flow Characteristic of Load Sensing Pump

2010 ◽  
Author(s):  
Chong Ma ◽  
Xiaowu Kong
Keyword(s):  
Steady State ◽  
Control Valve ◽  
Test Results ◽  
Steady State Flow ◽  
Load Pressure ◽  
Load Sensing ◽  
State Flow ◽  
Throttle Valve ◽  
Output Flow ◽  
The Impact

Aiming at studying the impact of steady-state flow force to YL-56 load sensing pump and how to reduce the effects of flow force on control valve spool, the factors of steady-state flow force were analyzed using CFD software FLUENT, and virtual prototype of load sensing pump was developed to study its characteristics. Compared with the effect of using position-controlled proportional solenoid to drive the throttle valve in simulation, the use of force-controlled proportional solenoid could suppress the impact of steady-state flow force much better, and the problem that the output flow increased when load pressure rose was solved. The experiment test results indicate that using force-controlled proportional solenoid in throttle valve can decrease the impact of steady-state flow force quite well.

Numerical Study of the Characteristics of Rotary Spool Orifice in Water Hydraulics

2014 ◽  
Vol 716-717 ◽  
pp. 662-669
Author(s):  
Jin Jun Wu ◽  
You Sheng Yang ◽  
Jing Yuan Li ◽  
Ge Gang Yu ◽  
Zong Xia Jiao
Keyword(s):  
Steady State ◽  
High Performance ◽  
Numerical Study ◽  
Tap Water ◽  
Control Valve ◽  
Control Element ◽  
Steady State Flow ◽  
Pressure Drops ◽  
State Flow ◽  
Depth Study

The rotary control orifice, in which the relative angular openings are adjusted by the rotary motion of the spool, thus controlling the flow area and the flow passing through, is a basic control element of hydraulic control valve. It has several advantages, such as little minimal steady flow rate, good anti-contamination, small driving power, small opening and shutting shock, and etc., over the translational control orifice. The working medium is tap water. A model is developed and numerical studies are carried out to investigate the hydrodynamic characteristics of the rotary control orifice, including flow and pressure field, flow characteristics, flow torque. The relationships between the flow and the pressure drops, the efflux angle and the angular openings, the steady-state flow torque and the pressure drops as well as the angular openings are obtained. The results show that a) the orifice geometries have great effects on the efflux angle and the steady-state flow torque; b) Under the same openings and flow direction, the efflux angle is almost constant under different pressure drops. It is larger for meter-in flow than for meter-out flow and decreases with the increase of openings; c) The steady-state flow torque (including meter-in flowTsfinand meter-out flowTsfout) is proportional to the pressure drops and first increases and then decreases with the increase of openings, finally reaches zero at the fully opened position; d) The friction moment is proportional to the rotary speed so as the transient flow induced moment to the rotary acceleration. The in-depth study of the drag moment of rotary control orifice helps to design high performance rotary servo valve for robots. The in-depth study of the rotary control orifice provides a basis for developing high performance rotary control valve.

scholarly journals Steady-state modelling and performance of a rotary direct drive digital valve

2020 ◽  
Vol 53 (3-4) ◽  
pp. 311-319
Author(s):  
Yuesong Li
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Angular Displacement ◽  
Stepper Motor ◽  
Direct Drive ◽  
Rotary Valve ◽  
Steady State Flow ◽  
Load Pressure ◽  
State Flow ◽  
The Relationship

A rotary direct drive digital valve driven by a stepper motor was proposed. By analysing its working principle, the steady-state mathematical model reflecting the relationship between the pressure, the flow and the angular displacement was deduced. Based on this mathematical model, the models of the null valve coefficients, the zero leakage flow and the steady-state flow torque were given. The simulation shows that the relationship between the pressure and the flow of the rotary valve is nonlinear; however, under a constant load pressure, the flow characteristics and the steady-state flow torque characteristics of the rotary valve with rectangular throttle orifices are linear. The experimental results show that the flow is directly proportional to the steps of the stepper motor, and the proposed mathematical models are valid.

Investigation of Steady-State Flow Forces in Spool Valves of Different Geometries and at Different Oil Temperatures With the Help of Measurements and CFD Simulations

2016 ◽  
Author(s):  
Patrik Bordovsky ◽  
Hubertus Murrenhoff
Keyword(s):  
Fluid Flow ◽  
Steady State ◽  
Measurement Data ◽  
Control Valve ◽  
Steady State Flow ◽  
Cfd Simulations ◽  
State Flow ◽  
Axial Forces ◽  
Spool Valves ◽  
Force Characteristics

When designing an actuator for a spool type directional control valve, axial forces acting on the spool have to be estimated. The steady-state flow force is the dominant axial force, which usually acts in the closing direction of the valve. However, many factors such as the valve geometry and the oil properties influence the flow force characteristics. Investigations regarding their effects on steady-state flow forces are described within this paper. Different spool geometries of a test 2/2-way spool valve are used for steady-state flow force measurements at different oil temperatures. The measurement data are used for validation of CFD simulations, which are carried out to scrutinise the flow inside the valve. Besides the steady-state flow forces, the fluid flow angles at the inlet and the outlet of the spool chamber are analysed. The results show that the spool geometry has a significant influence both on the flow rate and the steady-state flow force characteristics. Especially, the shape of the control edge has an impact on the flow patterns and on the magnitudes of steady-state flow forces. Moreover, the inlet and outlet fluid flow angles do not correlate with the expected values, which are commonly used for an analytical estimation of the flow forces. Furthermore, the oil temperature leads to quantitative deviations of the steady-state flow forces.

Calibration 7" – Cutthroat Flume as New Size for Discharge Measurement at Free Flow Condition

2020 ◽  
Vol 38 (12A) ◽  
pp. 1783-1789
Author(s):  
Jaafar S. Matooq ◽  
Muna J. Ibraheem
Keyword(s):  
Steady State ◽  
Flow Condition ◽  
Laboratory Experiments ◽  
Free Flow ◽  
Experimental Program ◽  
Steady State Flow ◽  
Empirical Formulas ◽  
State Flow ◽  
Operation Conditions ◽  
Throat Width

 This paper aims to conduct a series of laboratory experiments in case of steady-state flow for the new size 7 ̋ throat width (not presented before) of the cutthroat flume. For this size, five different lengths were adopted 0.535, 0.46, 0.40, 0.325 and 0.27m these lengths were adopted based on the limitations of the available flume. The experimental program has been followed to investigate the hydraulic characteristic and introducing the calibrated formula for free flow application within the discharge ranged between 0.006 and 0.025 m3/s. The calibration result showed that, under suitable operation conditions, the suggested empirical formulas can accurately predict the values of discharge within an error ± 3%.

A Graphical Method for Storage Coefficient Determination from Quasi-Steady State Flow Data

1996 ◽  
Vol 27 (4) ◽  
pp. 247-254 ◽  
Author(s):  
Zekâi Şen
Keyword(s):  
Steady State ◽  
Graphical Method ◽  
Pumping Test ◽  
Quasi Steady State ◽  
Flow Data ◽  
Steady State Flow ◽  
Storage Coefficient ◽  
State Flow ◽  
Aquifer Test

A simple, approximate but practical graphical method is proposed for estimating the storage coefficient independently from the transmissivity value, provided that quasi-steady state flow data are available from a pumping test. In the past, quasi-steady state flow distance-drawdown data have been used for the determination of transmissivity only. The method is applicable to confined and leaky aquifers. The application of the method has been performed for various aquifer test data available in the groundwater literature. The results are within the practical limits of approximation compared with the unsteady state flow solutions.

Steady-State Flow Behavior of CO2 Foam

2004 ◽  
Author(s):  
J.S. Kim ◽  
Y. Dong ◽  
W.R. Rossen
Keyword(s):  
Steady State ◽  
Flow Behavior ◽  
Steady State Flow ◽  
State Flow ◽  
Co2 Foam
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