Study on Flow Characteristics of Valve Inlet Blockage

2014 ◽  
Vol 607 ◽  
pp. 294-297
Author(s):  
Yan Tao An ◽  
Ru Jian Ma ◽  
Dong Zhao
Keyword(s):  
Flow Characteristic ◽  
Characteristic Curve ◽  
Flow Characteristics ◽  
Control Valve ◽  
Differential Pressure ◽  
Pressure Flow ◽  
Relative Gain ◽  
Flow Change

The flow characteristic and differential pressure-flow of inlet blockage fault and trouble-free for control valve are numerical simulated by CFD. The study shows that relative gain of flow characteristic curve for inlet blockage is increased, and it enhances the influence on fluctuation to flow change. The flow is less than the trouble-free at the same pressure, and with the increase of the differential pressure, flow difference of comparing with trouble-free increases gradually.

Study on Control Quality of Valve Outlet Blockage Fault

2014 ◽  
Vol 983 ◽  
pp. 424-427
Author(s):  
Yan Tao An ◽  
Ru Jian Ma ◽  
Dong Zhao
Keyword(s):  
Flow Characteristic ◽  
Characteristic Curve ◽  
Control Valve ◽  
Differential Pressure ◽  
Pressure Flow ◽  
Relative Gain ◽  
Control Quality ◽  
Maximum Value

The flow characteristic and differential pressure-flow of outlet blockage fault and trouble-free for control valve are simulated by CFD. The study shows that the vortex at the bottom of control valve outlet is main reason for the outlet blockage fault, relative gain of flow characteristic curve for outlet blockage is increased, the flow percentage of outlet blockage compared with trouble-free is maximum value at relative opening is 60% and 100%, the pressure - flow percentage reaches maximum value at differential pressure is 800 kPa.

Optimization of Nonlinear Pressure-flow Characteristics of a Spring- Loaded Pressure Relief Valve Based on CFD Simulation

2021 ◽  
Author(s):  
Chengshuo Wu ◽  
Shiyang Li ◽  
Qianqian Li ◽  
Peng Wu ◽  
Bin Huang ◽  
...  
Keyword(s):  
Flow Characteristic ◽  
Characteristic Curve ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Relief Valve ◽  
Pressure Flow ◽  
Hydraulic Force ◽  
Middle Chamber ◽  
Valve Opening ◽  
Cfd Method

Abstract In this study, the nonlinear pressure-flow characteristics of a spring-loaded pressure relief valve (PRV) which is used in the automotive fuel supply system for pressure control is analyzed, and its characteristics are improved by means of geometrical modifications of the valve structure. Given the complexity of the coupling mechanism between the valve internal flow characteristics and spring system, a quasi-steady computational fluid dynamics (CFD) method is introduced to predict the nonlinear pressure-flow characteristic curve of the valve and the accuracy is validated by experimental data. The total hydraulic force on the valve spool and diaphragm are divided into three parts according to the position of action and the correlation between the internal flow characteristics, hydraulic force, and pressure-flow characteristics of the valve are explained by CFD analysis and visualization. The result shows that the quasi-steady CFD method can accurately predict the trends of the valve nonlinear pressure-flow characteristic curve which is mainly determined by the hydraulic force produced in the middle chamber of the valve, when the valve opening reaches a certain value, a main vortex would be formulated in the middle chamber and lead to the sudden increase of hydraulic force which causes the fluctuation of the pressure-flow characteristic curve of the valve. It was also found that by increasing the round corner size, the valve opening value of flow pattern change will be promoted and the valve pressure-flow characteristic can be optimized.

On the Stability of the Flow of Gas out of a Compressor

1953 ◽  
Vol 57 (509) ◽  
pp. 345-346
Author(s):  
J. M. Stephenson
Keyword(s):  
Mach Number ◽  
Flow Characteristic ◽  
Flow Characteristics ◽  
Negative Slope ◽  
Pressure Flow ◽  
Damped Oscillations ◽  
Wide Range ◽  
High Mach ◽  
The Stability ◽  
Stable Flow

It is often supposed that the flow of gas from a compressor is, or should be, stable if the pressure-flow characteristic has a negative slope. It is shown here that this is only true if the Mach number is zero, i.e. if the machine is pumping a liquid. As the Mach number is increased towards one, a third regime becomes more and more important, wherein disturbances give rise to damped oscillations. The flow in this regime is stable in the mathematical, but not in the physical sense, since disturbances can occur all the time.Two conclusions can be drawn. First, although compressors with “flat” pressure-flow characteristics have a wide range of stable flow at low speeds, they are poor at high Mach numbers, where the flat part cannot be used. Next, the actual points on the characteristics at which the flow becomes unstable are not fixed, but depend to a large extent on the steadiness of the entry flow.

A Test System of Flow Characteristic Based upon PLC for Control Valve

2010 ◽  
Vol 43 ◽  
pp. 14-16
Author(s):  
Geng Fang Wang
Keyword(s):  
Flow Curve ◽  
Flow Characteristic ◽  
Flow Characteristics ◽  
Control Valve ◽  
Design Feature ◽  
Automatic Measurement ◽  
Resistance Coefficient ◽  
Test System ◽  
Flow Coefficient ◽  
Easy Operation

The flow characteristics of control valve are very important to product quality. For measuring the flow coefficient and flow curve accurately and all-rounding, we have designed a test system,which worked with PLC, it can measure the flow characteristics and resistance coefficient of control valve. The main purpose of this study was to bring out the work elements, design feature, and test software.The study we have performed showed that this test system is reasonable, easy to support entire automatic measurement with high precision and easy operation.

Investigation of suction flow characteristic in the inertance hydraulic converters for efficiency improvement

2021 ◽  
pp. 095965182110248
Author(s):  
Xiaoming Chen ◽  
Yuchuan Zhu ◽  
Travis Wiens ◽  
Doug Bitner ◽  
Minghao Tai ◽  
...  
Keyword(s):  
Flow Rate ◽  
Flow Characteristic ◽  
Performance Indicator ◽  
Flow Characteristics ◽  
Check Valve ◽  
Analytical Models ◽  
Switching Frequency ◽  
Experimental Measurements ◽  
Efficiency Improvement ◽  
Suction Flow

The inertance hydraulic converter relies on fluid inertance to modulate flow or pressure and is considered to be a competitive alternative to the conventional proportional hydraulic system due to its potential advantage in efficiency. As the quantification of fluid inertance, the suction flow characteristic is the crucial performance indicator for efficiency improvement. To explore the discrepancy between the passive inertance hydraulic converter featured by the check valve and the active inertance hydraulic converter driven by an equivalent 2/3 way fast switching valve in regard to suction flow characteristics, analytical models of the inertance hydraulic converters were established in MATLAB/Simulink. The validated models of the respective suction components were incorporated in the overall analytical models and their suction flow characteristics were theoretically and experimentally discussed. The analytical predictions and experimental measurements for the current configurations indicated that the active inertance hydraulic converter yields a larger transient suction flow rate than that of the passive inertance hydraulic converter due to the difference of the respective suction components. The suction flow characteristic can be modulated using the supply pressure and duty cycle, which was confirmed by experimental measurements. In addition, the suction flow characteristics are heavily affected by the resistance of the suction flow passage and switching frequency. There is a compromise between the resistance and switching frequency for inertance hydraulic converters to achieve large suction flow rate.

Pressure-Flow Characteristics During Peristaltic Transport of Non-Newtonian Fluid in Distensible Tube With Different Wave Forms

2003 ◽  
Author(s):  
Prasanna Hariharan ◽  
Rupak K. Banerjee
Keyword(s):  
Newtonian Fluid ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Pressure Flow ◽  
Square Wave ◽  
Wall Movement ◽  
Power Law Fluids ◽  
Significant Difference ◽  
Wave Forms ◽  
Distensible Tube

This study analyzes the pressure-flow characteristics during the peristaltic pumping of power law fluids in an axi-symmetric non-uniform distensible tube. The analyzed geometry is of a diverging shape that is common in several biological flow conduits, especially in mammals. Using the Fourier series, the dimensionless wall coordinates for sinusoidal, triangular, trapezoidal, and square wave forms are obtained to simulate wall movement. Equations expressing the pressure-flow rate relationship for different wall shapes are developed from the wave equation. Pressure-flow and velocity plots are obtained by solving the equations numerically. The results indicate that there is significant difference in pressure-flow relationship between Newtonian and non-Newtonian fluid. Also, the maximum flow rate can be achieved when the wall movement follows a square wave form.

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