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.

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.

scholarly journals Unsteady Characteristics of Forward Multi-Wing Centrifugal Fan at Low Flow Rate

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 691 ◽  
Author(s):  
Lun ◽  
Ye ◽  
Lin ◽  
Ying ◽  
Wei
Keyword(s):  
Unsteady Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Boundary Layer Separation ◽  
Low Flow ◽  
Centrifugal Fan ◽  
Suction Surface ◽  
Cfd Method ◽  
Low Flow Rate

The unsteady flow characteristics of a forward multi-wing centrifugal fan under a low flow rate are studied using the computational fluid dynamics (CFD) method. This paper emphasizes the eddy current distribution in terms of the Q criterion method, as well as pressure fluctuation, frequency spectrum, and kinetic energy spectrum analysis of internal monitoring points in a forward multi-wing centrifugal fan. The numerical results show that abnormal eddies mainly appear at the volute outlet and near the volute tongue, boundary layer separation occurs near the suction surface of the blade, and shedding eddies appear at the trailing edge of the blade with the time evolution. The unsteady flow characteristics of a forward multi-wing centrifugal fan at a small flow rate provide significant physical insight into understanding the internal flow law.

A Method to Resolve Simulation of Discontinuous Flow Field: a Valve Example From Full Closing to Re-Closure

2021 ◽  
Author(s):  
Qingye Li ◽  
Kunpeng Li ◽  
Chaoyong Zong ◽  
Fengjie Zheng ◽  
Xueguan Song
Keyword(s):  
Flow Field ◽  
Flow Characteristics ◽  
Current Method ◽  
Simulation Method ◽  
Relief Valve ◽  
Discontinuous Flow ◽  
Matlab Program ◽  
The Matrix ◽  
Valve Opening ◽  
Scheme Language

Abstract In transient computational fluid dynamics (CFD) simulations, the continuity of the flow field is an essential prerequisite. However, continuous flows can be separated under certain conditions, such as the process from valve opening to re-closure. The current method often leaves a narrow gap to estimate the full closing status, which will introduce a deviation. To address this issue, a full closing numerical simulation method (FCNSM) is developed to solve the problem of simulation between discontinuous flow field (DFF) and continuous flow field (CFF). The matrix laboratory (MATLAB) program has been used to communicate Fluent as a server session to call the files Fluent and automatically execute text-based user interface (TUI) commands. The radial basis function (RBF) is used to construct the relationship between the variables of the flow field and the coordinates of mesh nodes, which can achieve the data transmission from a DFF to a CFF. Automatic stopping of transient calculations is achieved by passing variables among MATLAB program, scheme language, and user-defined functions (UDF) when a physical quantity reaches a set value. Based on this method, a transient simulation with a dynamic mesh of a 2-D model regarding a pressure relief valve (PRV) is performed to simulate the process of the valve from full closing to re-closure, the flow characteristics through the PRV are obtained using this method. This study makes it possible to use FCNSM for understanding dynamic characteristics from DFF to CFF.

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.

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.

scholarly journals Numerical Investigation on the Mechanism of Double-Volute Balancing Radial Hydraulic Force on the Centrifugal Pump

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 689
Author(s):  
Yuan ◽  
Yuan ◽  
Tang
Keyword(s):  
Centrifugal Pump ◽  
Cross Sections ◽  
Performance Test ◽  
Flow Characteristics ◽  
Radial Force ◽  
Transient Pressure ◽  
Force Magnitude ◽  
Hydraulic Force ◽  
Pump Head ◽  
Cfd Method

Double-volute is an effective technique to reduce radial hydraulic force on the centrifugal pump and thereby mitigate the pump-casing vibration induced by unsteady flow characteristics. The mechanism of the double-volute structure balancing radial force on the impeller and volute was investigated on the basis of volute cross-sections by using Computational Fluid Dynamics (CFD) method. The tested performances and simulated inner-flow characteristics of two pumps with single-volute and double-volute were compared in this paper. The performance-test results verify the veracity of CFD method and illustrate that double-volute pump has some losses in terms of pump head and operation efficiency. The numerical simulations reveal that double-volute pump has smaller radial-force magnitude than single-volute pump on the abnormal conditions. Steady pressure field and transient pressure variations of pumps were explored to account for radial-force characteristics of double-volute pump. Compared with the single-volute structure, obvious pressure increases were found in the upper chamber (single part) of the double-volute, while the static pressure decreased in the lower chamber (double chambers). This situation reduces the pressure difference between two volute cross-sections in the collinear radial direction, resulting in smaller radial hydraulic force. Moreover, the transient simulations present the same phenomenon. The radial-forces distribute more uniformly in the double-volute pump, which can alleviate some vibrations.

The Numerical Simulation of Internal Flow Field in Rotor Oil Pump

2012 ◽  
Vol 516-517 ◽  
pp. 1032-1035
Author(s):  
Chen Hai Guo ◽  
Jie Wen ◽  
Fei Dong
Keyword(s):  
Numerical Simulation ◽  
Velocity Vector ◽  
Flow Characteristic ◽  
Characteristic Curve ◽  
Maximum Velocity ◽  
Internal Flow ◽  
Experimental Result ◽  
Maximum Pressure ◽  
Oil Pump ◽  
Internal Velocity

Numerical simulation of rotor oil pump is completed by using SC/Tetra under variable conditions, which obtains the distribution of pressure and velocity. The pressure in the outlet oil chamber rises with rotation of rotor which makes the space smaller and smaller. In the result of postprocessor the maximum pressure is 4.3Mpa. This paper also studies on the internal velocity field distribution of pump body and pump cover. By the chart of velocity vector, fluid exists obvious reflow phenomenon. This is because of effection of the rotor rotation. The maximum velocity mainly exists in pump cover. Futhermore, flow characteristic curve is compared with the experimental result. The result basically shows the correctness of numerical simulation.

Three-Dimensional Simulation of the Intake Port Combination Effect on Intake Flow Characteristic in a Highly Intensified Diesel Engine

2013 ◽  
Vol 744 ◽  
pp. 211-214
Author(s):  
Hong Meng Li ◽  
Guo Xiu Li ◽  
Yuan Jing Hou ◽  
Yu Song Yu
Keyword(s):  
Diesel Engine ◽  
Flow Characteristic ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Intake Port ◽  
Intake Process ◽  
Instantaneous Flow Field ◽  
Dimensional Simulation ◽  
Cfd Method ◽  
Intake Flow

In this paper, the three-dimensional CFD method is used in numerical simulation of the highly intensified diesel engine intake process. The effect of different intake flow compound modes on the highly intensified diesel engine is studied (Including compounded port with helical and tangential intake port, compounded port with two helical intake ports and compounded port with two tangential intake ports). By contrasting the instantaneous flow field, flow characteristic and inlet ability of the three compound modes, the pattern of influence on the inlet flow characteristics by compound modes is analyzed. The results indicate that the combinations of the intake port greatly affect the swirl rate and the inlet ability. The interference of the two helical intake ports is serious, causing more inlet loss. The two helical intake ports have the weakest inlet ability among the three types of intake ports. However, two helical intake ports can cause higher swirl rate. Two tangential intake ports inlet ability is the most excellent, but its swirl rate is the lowest.

scholarly journals Analysis of Flow Characteristics and Effects of Turbulence Models for the Butterfly Valve

2021 ◽  
Vol 11 (14) ◽  
pp. 6319
Author(s):  
Sung-Woong Choi ◽  
Hyoung-Seock Seo ◽  
Han-Sang Kim
Keyword(s):  
Turbulence Model ◽  
Dissipation Rate ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Flow Properties ◽  
Nominal Diameter ◽  
Large Pressure ◽  
Sst Model ◽  
Turbulence Effect ◽  
Valve Opening

In the present study, the flow characteristics of butterfly valves with different sizes DN 80 (nominal diameter: 76.2 mm), DN 262 (nominal diameter: 254 mm), DN 400 (nominal diameter: 406 mm) were numerically investigated under different valve opening percentages. Representative two-equation turbulence models of two-equation k-epsilon model of Launder and Sharma, two-equation k-omega model of Wilcox, and two-equation k-omega SST model of Menter were selected. Flow characteristics of butterfly valves were examined to determine turbulence model effects. It was determined that increasing turbulence effect could cause many discrepancies between turbulence models, especially in areas with large pressure drop and velocity increase. In addition, sensitivity analysis of flow properties was conducted to determine the effect of constants used in each turbulence model. It was observed that the most sensitive flow properties were turbulence dissipation rate (Epsilon) for the k-epsilon turbulence model and turbulence specific dissipation rate (Omega) for the k-omega turbulence model.

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.

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