Computational fluid dynamics and experimental analysis of the influence of the energy recovery unit on the proportional relief valve

2017 ◽  
Vol 232 (4) ◽  
pp. 697-705 ◽  
Author(s):  
Tianliang Lin ◽  
Qiang Chen ◽  
Haoling Ren ◽  
Ruoxi Lv ◽  
Chen Miao ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Steady State ◽  
Energy Loss ◽  
Hydraulic System ◽  
Energy Recovery ◽  
Pressure Control ◽  
Steady State Flow ◽  
Relief Valve ◽  
Recovery Unit ◽  
Line Pressure

The overflow energy loss in relief valve, which is one of the main reasons leading to the low efficiency of the hydraulic system, had been considered to be impossible to solve. The principle of the overflow energy loss of the relief valve is analyzed and a novel method to reduce the overflow loss using an energy recovery unit, which can improve the return line pressure of the pilot proportional relief valve, is proposed. The influence of the energy recovery unit on the pressure control characteristics and steady-state flow force of the pilot proportional relief valve are discussed. The effects of the return line pressure on the distribution of the flow field and the pressure control characteristics are analyzed through computational fluid dynamics simulation and experiment. The results show that with the increase of the return line pressure, the displacement of the main valve spool increases and the reset spring force increases accordingly. While the steady-state flow force decreases dramatically with the increase of the return line pressure, which results in a smaller pressure differential the pressure differential can be reduced from 15% to 2.5%. It is also observed that the flow rate of the pilot proportional relief valve can be maintained at a certain value with a small oscillation and that the pilot proportional relief valve can release the redundant flow of hydraulic system. This verifies that the pilot proportional relief valve with the outlet connecting to the energy recovery unit to recovery the overflow energy loss cannot reduce the pressure control characteristics, but can achieve a better pressure control accuracy of the pilot proportional relief valve.

Steady State Characteristics of a Flapper-Nozzle Relief Valve

1987 ◽  
Vol 201 (2) ◽  
pp. 135-144 ◽  
Author(s):  
J S Yun ◽  
H S Cho
Keyword(s):  
Steady State ◽  
Pressure Control ◽  
Effective Area ◽  
Body Motion ◽  
Model Parameters ◽  
Dynamics Model ◽  
Relief Valve ◽  
Load Pressure ◽  
Hydraulic Load ◽  
The Relationship

The static and dynamic characteristics of flapper-nozzle type electromagnetic relief valves have not so far been investigated analytically in depth, although they have been widely used for hydraulic load pressure control. In this paper a non-linear model of the relief valve is formulated explicitly, based upon rigid-body motion and fluid dynamics. Model parameters such as discharge coefficients, effective area of the nozzle and the electromagnetic constant were identified from the steady state characteristics and physical dimensions of the valve. Based upon this constructed model the static characteristics such as the pressure override and the relationship between input current and main pressure were obtained analytically and compared with those obtained experimentally. The comparison shows that this constructed analytical model can precisely predict such characteristics.

In-Cylinder Flow Correlations Between Steady Flow Bench and Motored Engine Using Computational Fluid Dynamics

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Xiaofeng Yang ◽  
Tang-Wei Kuo ◽  
Orgun Guralp ◽  
Ronald O. Grover ◽  
Paul Najt
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Steady State ◽  
Velocity Profile ◽  
Discharge Coefficient ◽  
Intake Port ◽  
Charge Motion ◽  
Steady State Flow ◽  
Cfd Simulations ◽  
Motored Engine

Intake port flow performance plays a substantial role in determining the volumetric efficiency and in-cylinder charge motion of a spark-ignited engine. Steady-state flow bench and motored engine flow computational fluid dynamics (CFD) simulations were carried out to bridge these two approaches for the evaluation of port flow and charge motion (such as discharge coefficient, swirl/tumble ratios (SR/TR)). The intake port polar velocity profile and polar physical clearance profile were generated to evaluate the port performance based on local flow velocity and physical clearance in the valve-seat region. The measured data were taken from standard steady-state flow bench tests of an intake port for validation of CFD simulations. It was reconfirmed that the predicted discharge coefficients and swirl/tumble index (SI/TI) of steady flow bench simulations have a good correlation with those of motored engine flow simulations. Polar velocity profile is strongly affected by polar physical clearance profile. The polar velocity inhomogeneity factor (IHF) correlates well with the port discharge coefficient, swirl/tumble index. Useful information can be extracted from local polar physical clearance and velocity, which can help for intake port design.

scholarly journals Influence and Improvement of Hydraulic Power on Spool Valve Reversing

2021 ◽  
Vol 252 ◽  
pp. 02030
Author(s):  
Xue Mei ◽  
Lin Huili ◽  
Zheng Xiaoli
Keyword(s):  
Steady State ◽  
Hydraulic System ◽  
Transient Flow ◽  
Fluid Power ◽  
Steady State Flow ◽  
Hydraulic Power ◽  
Sliding Direction ◽  
State Flow ◽  
Spool Valve

This paper analysed the effect of steady-state flow force and transient flow force to sliding direction valve, and two examples were given to illustrate adverse consequences caused by excessive fluid power, put forward the compensation measures. The effect of flow force should be considered when designing the hydraulic system in order to make the hydraulic system work more stable.

scholarly journals Comparison of Aerodynamic Characteristics of NACA 0012 and NACA 2412 Airfoil

2021 ◽  
Vol 9 (VII) ◽  
pp. 2037-2045
Author(s):  
S. M Mehady Hasan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Steady State ◽  
Experimental Methods ◽  
Aerodynamic Characteristics ◽  
Steady State Flow ◽  
Pressure Contour ◽  
Computational Fluid Dynamics Cfd ◽  
Velocity Contour ◽  
Naca 0012

A comparison between NACA 0012 and NACA 2412 has been made by comparing the lift co- efficient, drag co-efficient, pressure contour and velocity contour at various angles of attack. The process has been done taking steady state flow around NACA-0012 and NACA-2412 airfoil using 1m chord length and a velocity of 88.65m/s. The main aim is to understand the aerodynamic characteristics of both the airfoils at different angles of attack and draw a conclusion on which performs better under the same conditions. Modelling and numerical analysis has been carried out by using commercially available CFD software, which is a convenient method of analysis since computational methods are more preferred to experimental methods due to low expenses involved. The numerical results demonstrated are compatible with those of the theory. This confirms the validity of using Computational Fluid Dynamics (CFD) as a reliable alternative to experimental procedures.

scholarly journals Overflow Energy Loss Recovery System Based on Hydraulic Motor-Electric Generator

2021 ◽  
Vol 11 (3) ◽  
pp. 941
Author(s):  
Zhongshen Li ◽  
Ling Su ◽  
Tianliang Lin
Keyword(s):  
Hydraulic System ◽  
Energy Recovery ◽  
Pressure Differential ◽  
Normal Operation ◽  
Step Response ◽  
Hydraulic Motor ◽  
Relief Valve ◽  
Loss Recovery ◽  
Electric Generator ◽  
Recovery System

Overflow loss is one of the main reasons for the inefficiency of the hydraulic system. Aiming at the overflow loss in the hydraulic system, an energy recovery system based on a hydraulic motor and generator is proposed. Further, a pressure monitoring and control strategy based on variable speed control for electric generator is adopted, which can control the pressure differential between the inlet and outlet of the proportional relief valve as a small value, and achieve the purpose of energy recovery by reducing the loss of the pressure differential between the inlet and outlet of the relief valve. Through establishing a simulation system model and test platform, the stability, step response characteristics and energy saving of the system are studied. The results show that the energy recovery unit at the outlet of the relief valve does not affect the normal operation of the relief valve, but also greatly reduces the pressure regulation deviation. Besides, the efficiency of overflow loss recovery system about is 67%.

Energy Saving in Electro-Hydraulic System Using a MIMO Fuzzy Controller

2012 ◽  
Vol 622-623 ◽  
pp. 75-79 ◽  
Author(s):  
Pornjit Pratumsuwan ◽  
Santi Hutamarn ◽  
Watcharin Po-Ngaen
Keyword(s):  
Power Consumption ◽  
Energy Saving ◽  
Hydraulic System ◽  
Fuzzy Controller ◽  
Asynchronous Motor ◽  
Pressure Control ◽  
Experimental Result ◽  
Relief Valve ◽  
Load Pressure ◽  
Reduce Power Consumption

Energy saving in the electro-hydraulic system (EHS) that currently exists in most inverter used to adjust speed of the asynchronous motor (ASM) which drive a fixed displacement pump. The most controller commonly used control system such as PID and multi-input single-output (MISO) fuzzy controller. In this paper, a multi-input multi-output (MIMO) fuzzy controller is used to improve the energy saving performance of the EHS. The proposed controller is designed to control the pressure of the EHS to suit the actual needs of the load. The two inputs of controller received signals from the error and change in error of the load pressure of the EHS. For the two outputs of the controller, one output is used to control the inverter to adjust speed of an ASM which drive hydraulic pump, and one output that is used for control proportional pressure relief valve. The proposed controller was implemented to pressure control of compression machine. The experimental result showed that using a proposed controller can reduce power consumption was higher than compared with PID and MISO fuzzy controllers. Particularly, a MIMO fuzzy controller can reduce power consumption by up to 70.22% when compared to the conventional system.

scholarly journals Static Characteristics of Pressure Control Valve

2017 ◽  
Vol 67 (1) ◽  
pp. 119-124
Author(s):  
Ondřej Vykoukal ◽  
Lumír Hružík ◽  
Adam Bureček
Keyword(s):  
Experimental Measurement ◽  
Hydraulic System ◽  
Check Valve ◽  
Control Valve ◽  
Pressure Control ◽  
Static Characteristics ◽  
Hydraulic Pump ◽  
Relief Valve ◽  
Pressure Control Valve

Abstract The article deals with the measurement of static characteristics of a pressure control valve. The pressure, at which the valve starts to leak oil, is adjusted by a spring. The measurement is performed on a hydraulic system that consists of tank, hydraulic pump, check valve, relief valve and pressure control valve which is measured. The results of this experimental measurement are Δp - Q characteristics of the pressure control valve for various pressure settings.

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%.

Effect of Viscous Dissipation on MHD Williamson Nanofluid Flow in a Porous Medium

2019 ◽  
Vol 8 (3) ◽  
pp. 5795-5802 ◽  
Keyword(s):  
Porous Medium ◽  
Steady State ◽  
Numerical Solution ◽  
Viscous Dissipation ◽  
Flow Problem ◽  
Numerical Study ◽  
Steady State Flow ◽  
Nanofluid Flow ◽  
Shooting Technique ◽  
Order Four

The main objective of this paper is to focus on a numerical study of viscous dissipation effect on the steady state flow of MHD Williamson nanofluid. A mathematical modeled which resembles the physical flow problem has been developed. By using an appropriate transformation, we converted the system of dimensional PDEs (nonlinear) into coupled dimensionless ODEs. The numerical solution of these modeled ordinary differential equations (ODEs) is achieved by utilizing shooting technique together with Adams-Bashforth Moulton method of order four. Finally, the results of discussed for different parameters through graphs and tables.

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