Unsteady Flow Simulation of Directional Control Valve in Electro-Hydraulic Systems by Numerical Analysis

2014 ◽  
Vol 607 ◽  
pp. 382-385
Author(s):  
Aphaiwong Junchangpood
Keyword(s):  
Numerical Analysis ◽  
Pressure Drop ◽  
Real Time ◽  
Hydraulic System ◽  
Transient Flow ◽  
Pressure Coefficient ◽  
Control Valve ◽  
The Real ◽  
Directional Control ◽  
Directional Control Valve

The objective of the present paper is a numerical analysis of the transient flow through a 4/3 hydraulic closed center direction control valve. The real-time discharge coefficients corresponding to supply flow difference have been considered. In order to develop an intelligent control system for an electro-hydraulic system (EHS), a new controller has recently been proposed to control those parameters in a complex system. However, a mathematical model of the EHS including the transient parameters has not been clarified. The main objective of this paper is to numerically analyze the dynamic characteristics of the directional control valve and also the flow behaviors in the electro-hydraulic system control. Both the steady state and transient flow though the valve which affect to flow-pressure coefficient were numerically considered. Moreover, this paper presents numerical results, which explain the flow behaviors related with the real-time pressure drop and discharge coefficient. Both a high inlet flow and a large opening spool have determined the pressure drop increment.

CFD Analysis of Energy Loss of Direction Control Valve in Electro-Hydraulic Systems with Inverter

2014 ◽  
Vol 607 ◽  
pp. 393-396
Author(s):  
Aphaiwong Junchangpood
Keyword(s):  
Energy Loss ◽  
Transient Flow ◽  
Pressure Coefficient ◽  
Control Valve ◽  
Hydraulic Systems ◽  
Control Approach ◽  
Directional Control ◽  
Direction Control ◽  
Flow Pressure ◽  
Directional Control Valve

This paper presents a new approach for reducing energy consumption coupled with force and position controls in the electro-hydraulic systems (EHS). The EHS inverter will be added for control to vary the speed of electric motor driven hydraulic pump. In addition, a single directional control valve is used to control the system parameters, which cause loss of energy. The main objective of this research is to numerically analyze the energy loss in the new control approach in the EHS with the inverter by using a simple directional control valve. The spool displacements of 4/3 hydraulic closed center directional control valve, transient flow-pressure coefficient and energy loss were simulated with computational fluid dynamics (CFD). In addition, this paper presents CFD results. The relationships of flow rate variables with time-dependent pressure drop and energy loss were addressed. The flow behaviors related with transient flow-pressure coefficients were also discussed. It is found that the loss of energy increases, depending on both the large opening spool displacement and the inlet flow variable.

Study on Static and Dynamic Characteristics of Load-Sensing and Pressure-Compensated Directional Control Valve

2013 ◽  
Vol 753-755 ◽  
pp. 2693-2699 ◽  
Author(s):  
Rui Lin Feng ◽  
Jian Hua Wei ◽  
Jin Hui Fang
Keyword(s):  
Transfer Function ◽  
Working Conditions ◽  
Dynamic Characteristics ◽  
Pressure Coefficient ◽  
Control Valve ◽  
Parameters Optimization ◽  
Static And Dynamic Characteristics ◽  
Load Sensing ◽  
Directional Control ◽  
Directional Control Valve

This study presents the static and dynamic characteristics of load-sensing and pressure-compensated directional control valve under the working conditions. A mathematical model is developed, two types of working conditions are presented through the static work point calculation. The static characteristic is analyzed by simulation, and the conclusion is validated by experiments. Solution procedure of the flow gain transfer function and flow-pressure coefficient transfer function is detailed introduced based on the above static computation, and their dynamic characteristic is analyzed by using Bode diagram. Finally, three types of compensatory modes are proposed, which provides very useful value and significance for the hydraulic component or system design and parameters optimization.

Research into the Characteristics of Slewing Hydraulic System on Truck Crane

2011 ◽  
Vol 317-319 ◽  
pp. 2409-2415 ◽  
Author(s):  
Hai Bo Xie ◽  
Jian Liu ◽  
Hua Yong Yang ◽  
Yu Zhen ◽  
Jin Zhang
Keyword(s):  
Simulation Model ◽  
Hydraulic System ◽  
Control Valve ◽  
Work Conditions ◽  
The Core ◽  
Hydraulic Impact ◽  
Directional Control ◽  
System Pressure ◽  
High System ◽  
Directional Control Valve

The domestic 25-ton truck crane has the problems of high system pressure during steady slewing and great hydraulic impact when slewing motion starts and brakes. So the simulation model of the slewing hydraulic system and the core hydraulic components was constructed by AMESim. The flow areas of throttling grooves on the valve rod of the directional control valve were calculated by Matlab and converted into text files, which were imported into the simulation model. To get the load parameters of slewing system in different work conditions, an experiment on real truck crane was performed. Then the problem work conditions recurred in the simulation, which showed the veracity of the simulation model. Based on the simulation model an improving method was presented and simulated and the simulation results showed that through the improving method, the system pressure and the hydraulic impact could be efficiently reduced.

Design and Analysis of a Two-Valve Control Hydraulic System for Controllable Pitch Propeller

2012 ◽  
Vol 468-471 ◽  
pp. 122-126
Author(s):  
Chang Jun Zhang ◽  
Jing Li ◽  
Hong Gang Jiang ◽  
Yun Chen ◽  
Yao Bao Yin
Keyword(s):  
Hydraulic System ◽  
Simulation Analysis ◽  
Control Valve ◽  
Proportional Valve ◽  
Directional Control ◽  
Parallel Control ◽  
The Relationship ◽  
Valve Control ◽  
Control Accuracy ◽  
Directional Control Valve

This paper designs a two-valve control hydraulic system for controllable pitch propeller which consists of an electro-hydraulic directional control valve and a proportional directional control valve. The parallel control strategy is proposed and respective controllers are determined for the system. It yields out the relationship between the control parameters and valves characteristics by modeling and simulation analysis. Also the influence of the proportional valve flow rate on pitch control accuracy is discussed.

scholarly journals CFD Simulation of a Post-Compensated Load Sensing Directional Control Valve

2021 ◽  
Vol 312 ◽  
pp. 05002
Author(s):  
Paola Fresia ◽  
Massimo Rundo
Keyword(s):  
Pressure Drop ◽  
Cfd Simulation ◽  
Control Valve ◽  
Design Tool ◽  
Lumped Parameter Model ◽  
Cfd Model ◽  
Load Sensing ◽  
Directional Control ◽  
Lumped Parameter ◽  
Directional Control Valve

The paper presents the CFD model of a load sensing directional control valve. The model was validated experimentally in terms of pressure drop and flow force at different positions of the spool. The spool position was imposed manually by means of a micrometric screw and a load cell was used for measuring the flow force. The CFD model was developed with the CAD-embedded tool FloEFD®. The model has been proved to be very reliable in estimating the pressure drop, moreover quite good results were obtained also in the evaluation of the flow force. The CFD simulations were used to tune the coefficients of a lumped parameter model of the valve, so that such a model can be efficiently used for the simulation of an entire hydraulic circuit. Moreover, the CFD model has been used as design tool for attenuating the detrimental effect of the flow force. In particular, the width of the land upstream of the metering edge has an influence on the resultant force on the spool. If was found that it is possible to significantly reduce the flow force at maximum opening with a relatively small increment of the pressure drop across the valve.

scholarly journals Research of stability of Load-sensing hydraulic drive operation, on the base of multimode directional control valve

2021 ◽  
Vol 12 (2) ◽  
pp. 93-99
Author(s):  
Oleksandr Petrov ◽  
◽  
Leonid Kozlov ◽  
Natalia Semichastnova ◽  
Olha Zavalniuk ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Energy Efficient ◽  
Hydraulic Drive ◽  
Control Valve ◽  
Design Parameters ◽  
Hydraulic Motor ◽  
Load Sensing ◽  
Directional Control ◽  
The Stability ◽  
Directional Control Valve

The article describes a new scheme of a hydraulic drive, which, thanks to the original design of a multimode directional control valve, has energy-efficient properties that are characteristic of load-sensing hydraulic drives. The proposed design of the multimode directional control valve ensures the operation of the hydraulic drive in four modes – unloading the hydraulic pump, regulating the flow of the hydraulic motor, the maximum flow of the hydraulic motor and protection against overload. In each of these modes, the hydraulic drive operates with low power losses due to the presence of a constant balancing pressure drop. This value is formed by a combination of design parameters of the directional control valve. The proposed value of the value of the balancing pressure drop of 0,7-0,8 MPa provides high energy efficiency of the hydraulic drive in the most critical operating mode – regulation of the hydraulic motor flow. In order to ensure the stability of the energy-efficient operation of the hydraulic drive in this mode, a research was made of the stability of transient processes with various combinations of design parameters of the overflow valve of the hydraulic control valve, as well as changes in the operating conditions of the hydraulic drive. As a result of theoretical researches, on the basis of mathematical modeling of working processes, combinations of design parameters of the hydraulic lock and the spool of the overflow valve were identified, which ensure the stability of the hydraulic drive in the mode of regulating the flow of the hydraulic motor. In particular, these are such parameters as the stiffness of the springs of the hydraulic lock and the overflow valve, the diameter and angle of inclination of the edge of the overflow valve spool, the area of the radial holes and the auxiliary choke of the overflow valve. It was also determined that in this mode, the stability of the hydraulic drive will be ensured under conditions of a load pressure of up to 20 MPa, a hydraulic motor flow rate of 100 l / min and a working fluid temperature of 80 °C.

Study on Dynamic Characteristics of DC Valve in Electro-Hydraulic System Using CFD Simulation

2014 ◽  
Vol 619 ◽  
pp. 278-282
Author(s):  
Aphaiwong Junchangpood
Keyword(s):  
Dynamic Characteristics ◽  
Hydraulic System ◽  
Cfd Simulation ◽  
Fuzzy Controller ◽  
Pressure Coefficient ◽  
Control Valve ◽  
System Control ◽  
Directional Control ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Pressure

The development of an intelligence control system has presently been widely studied for application in areas of automation industries, especially an electro-hydraulic system (EHS). Usually, it has the position, force and speed controls which are sensitive to change in the system parameters. Hence, a multi-input multi-output (MIMO) fuzzy controller has recently been proposed to control those parameters in a complex system. However, a mathematical model of the EHS which included the dynamic parameters has not yet been clarified. The objective of this paper is to analyze numerically the dynamic characteristics of the directional control valve (DCV) and also the flow behaviors in the electro-hydraulic system control. The spool displacements of 4/3 hydraulic closed center DCV and flow-pressure coefficient were simulated with the computational fluid dynamics (CFD). Furthermore, this paper presents CFD results, which explain the flow behaviors related with the dynamic characteristics of flow-pressure coefficient. The simulation results show that those coefficients show non-linear correlation with the opening spool displacements.

Analyzing the Familiar Failures and its Elimination of Hydraulic System which Affect the Processing Precision Grinding Machine

2009 ◽  
Vol 416 ◽  
pp. 238-242
Author(s):  
Yong Tian ◽  
Xian Zhou Cao
Keyword(s):  
Hydraulic System ◽  
Control Valve ◽  
Precision Grinding ◽  
Directional Control ◽  
Start Up ◽  
Movable Platform ◽  
Grinding Machine ◽  
Directional Control Valve

Analyze the familiar failures and its elimination of hydraulic system which affect the processing precision of grinding machine. Find out mostly problems of the hydraulic system. Movable platform ‘crawl’; the velocity disaccord of the movable platform moving out and home; the rapidity falls short of theory value when the movable platform moves speediness; when the movable platform is being start-up or stop, it may rush ahead suddenly; the positions’ precision of the movable platform is affected by the three-position directional control valve. The temperature of oil is too high when the machine is working etc. Bring forward the method how to eliminate these failures. These can offer some reference for grinding machine on its design, use, maintenance etc.

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