scholarly journals Numerical Analysis to the Effect of Guiding Plate on Flow Characteristics in a Ball Valve

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 69 ◽  
Author(s):  
Yanping Wang ◽  
Chaoning Zhu ◽  
Guang Zhang ◽  
Dejing Wang ◽  
Minghe Jiang ◽  
...  
Keyword(s):  
High Speed ◽  
Flow Characteristics ◽  
Resistance Coefficient ◽  
Ball Valve ◽  
Flow Coefficient ◽  
Internal Erosion ◽  
Jet Flows ◽  
Gap Flow ◽  
The Stability ◽  
Downstream Flow

When internal flows go through a valve with a small opening degree, high-speed jet flows are induced, which causes the erosion of the valve core and affects the stability of the flow field. Setting guiding plates in the valve behind the valve core has the function of reducing the adverse effect of high-speed jet flows. In this work, numerical simulations were carried out to investigate the effect of the guiding plate on flow and resistance coefficient, velocity and pressure distributions and flow stability downstream of the valve. The number of guiding plates was changed from 0 to 3 and the opening degree was varied from 0 to 100% at intervals of 10%. A guiding plate with holes in it plays the role of bypassing and guiding flow. Under the action of the guiding plate, the flow coefficient obviously decreases, the gap flow between the valve core and the valve wall in the top of the valve are modified, and the gap flow even disappeared in the valve with 3 guiding plates. It was found that setting the guiding plate can improve the performance of the ball valve, reducing the internal erosion and increasing the stability of valve downstream flow efficiently.

scholarly journals Self-Recirculating Casing Treatment Concept for Enhanced Compressor Performance

2002 ◽  
Author(s):  
Michael D. Hathaway
Keyword(s):  
High Speed ◽  
Flow Characteristics ◽  
Treatment Concept ◽  
Casing Treatment ◽  
Compressor Performance ◽  
And Performance ◽  
The Stability ◽  
The Impact ◽  
Compressor Efficiency ◽  
Transonic Rotor

A state-of-the-art CFD code (APNASA) was employed in a computationally based investigation of the impact of casing bleed and injection on the stability and performance of a moderate speed fan rotor wherein the stalling mass flow is controlled by tip flow field breakdown. The investigation was guided by observed trends in endwall flow characteristics (e.g., increasing endwall aerodynamic blockage) as stall is approached, and based on the hypothesis that application of bleed or injection can mitigate these trends. The “best” bleed and injection configurations were then combined to yield a self-recirculating casing treatment concept. The results of this investigation yielded: 1) identification of the fluid mechanisms which precipitate stall of tip critical blade rows, and 2) an approach to recirculated casing treatment which results in increased compressor stall range with minimal or no loss in efficiency. Subsequent application of this approach to a high speed transonic rotor successfully yielded significant improvements in stall range with no loss in compressor efficiency.

A Study on the Flow Characteristics in a Plug Valve With Various Port Shapes

2002 ◽  
Author(s):  
T.-A. Kim ◽  
B.-J. Ahn ◽  
Youn J. Kim
Keyword(s):  
Rate Control ◽  
Velocity Vector ◽  
Static Pressure ◽  
Flow Characteristics ◽  
Resistance Coefficient ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Improve Performance ◽  
Flow Rate Control ◽  
Plug Valve

Analyses on the characteristics of flow fields in the plug valve are required to improve performance and safety at severe operating conditions such as high-pressure and high-temperature. In this study, numerical and experimental analyses are carried out with various opening rates of the valve and the shapes of the plug port: circular, triangle, and modified triangle shapes. Especially, the distributions of the static pressure, velocity vector and streamlines are investigated to calculate the flow coefficient (Cv) and the resistance coefficient (K) in each opening rate and shape. For the case of full open, the static pressure passed through the valve port has almost been recovered. However, in case of other opening rates, pressure has not permanently recovered due to pressure drop leading to loss. This phenomenon in each shape of the valve shows the different behaviors. Result of calculation show that the modified triangle shape is good on flow characteristics and the triangle one is good for the flow rate control.

scholarly journals Comparative analysis of regulating characteristics between air-ring flow regulating valve and center butterfly valve

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251943
Author(s):  
Shixian Wu ◽  
Heqing Liu ◽  
Yongping Chen
Keyword(s):  
Flow Resistance ◽  
Flow Characteristics ◽  
Maximum Velocity ◽  
Experimental System ◽  
Resistance Coefficient ◽  
Flow Coefficient ◽  
Pipeline System ◽  
Butterfly Valve ◽  
Abrasive Erosion ◽  
Valve Opening

In this study, a novel air-ring flow regulating valve was proposed to reduce the flow resistance caused by valve structural pressure drop in fluid transportation pipeline system. The regulating characteristics at different valve openings were analyzed by numerical method and the results were compared with the center butterfly valve which is most widely applied in fluid transportation pipeline system. Besides, an experimental system was designed to validate the numerical model in the present study. The results indicated that the simulation results agree well with experimental data. The resistance coefficient of the air-ring flow regulating valve is smaller than that of the center butterfly valve when the valve opening is greater than 67%, and the resistance coefficient is reduced by up to 100% as the valve is fully opened. Both valves maintain approximately equal percentage flow characteristics, the deviation in relative flow coefficient is small. In addition, the wall shear stress of the air-ring flow regulating valve is much smaller than that of the center butterfly valve at the same valve opening, and the maximum velocity in the pipeline system is always smaller than that of the center butterfly valve, which significantly reduces valve surface abrasive erosion and thus prolongs its service life.

Analysis and comparison of steady-state performance characteristics of two-axial groove and multilobe hydrodynamic bearings lubricated with non-Newtonian fluids

2018 ◽  
Vol 232 (12) ◽  
pp. 1581-1596 ◽  
Author(s):  
Bhrigu Jyoti Das ◽  
Lintu Roy
Keyword(s):  
Steady State ◽  
High Speed ◽  
Journal Bearing ◽  
Maximum Flow ◽  
Maximum Load ◽  
Performance Characteristics ◽  
Flow Coefficient ◽  
Rotating Speed ◽  
The Stability ◽  
Steady State Performance

Rotating machines are one of the most important and widely used machineries in the modern engineering world. They are also the required to run at high rotating speed. The plain journal bearing is mostly replaced by some other bearing, as it does not suit the stability requirement of high-speed machines and precision machine tools. In order to improve the stability of a circular bearing, many researchers tried to change its geometrical configuration. In view of this, an attempt has been made in the present work to study the performance characteristics of four different bearing configurations using non-Newtonian lubricant and comparison of the results has been made with plain journal bearing. To calculate the steady-state performance characteristics, nondimensional form of the Reynolds equation using non-Newtonian lubricant has been written and solved for the steady-state nondimensional pressure distribution in a finite grid using finite difference method with successive over-relaxation technique satisfying appropriate boundary condition. From the study, it can be concluded that three-lobe bearing have maximum load-carrying capacity and minimum friction variable, whereas two-lobe bearing have maximum flow coefficient.

scholarly journals Numerical Study of the Microflow Characteristics in a V-ball Valve

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 155
Author(s):  
Zhi-xin Gao ◽  
Yang Yue ◽  
Jia-ming Yang ◽  
Jun-ye Li ◽  
Hui Wu ◽  
...  
Keyword(s):  
Numerical Study ◽  
Flow Characteristics ◽  
Ball Valve ◽  
Loss Coefficient ◽  
Flow Coefficient ◽  
Process Industries ◽  
Opposite Trend ◽  
Small Flow ◽  
Valve Opening ◽  
Flow Cross

V-ball valves are widely applied in many process industries to regulate fluid flow, and they have advantages of good approximately equal percentage flow characteristics and easy maintenance. However, in some applications, the V-ball valve needs to have good performance under both large and extremely small flow coefficients. In this paper, the improvement of the original V-ball valve is made and the flow characteristics between the original and the improved V-ball valve are compared. Two types of small gaps are added to the original V-ball, namely the gap with an approximately rectangular port and the gap with an approximately triangular port. The effects of the structure and the dimension of the gap on flow characteristics are investigated. Results show that within the gap, the flow coefficient increases but the loss coefficient decreases as the valve opening increases, and the flow coefficient has an approximately linear relationship with the flow cross-area of the added gap. Results also show that under the same flow cross-area, the flow coefficient has a higher value if the distance between the gap and the ball center is greater or if the gap is an approximately rectangular port, while the loss coefficient has an opposite trend.

scholarly journals Effect of variable speed motion curve of electric actuator on ball valve performance and internal flow field

2021 ◽  
Vol 13 (6) ◽  
pp. 168781402110280
Author(s):  
Guangfei Ma ◽  
Zhe Lin ◽  
Zuchao Zhu ◽  
Yong Fang
Keyword(s):  
Flow Field ◽  
Internal Flow ◽  
Economic Cost ◽  
Resistance Coefficient ◽  
Transportation Systems ◽  
Ball Valve ◽  
Flow Coefficient ◽  
Variable Speed ◽  
Pipeline Transportation ◽  
Electric Actuator

Ball valve is an important control component in the pipeline transportation system. It is widely used in pipeline transportation systems to control the pressure and flow parameters of the conveying medium. Based on the user-defined UDF technology and the standard k-[Formula: see text] turbulence model using computational fluid dynamics techniques, the transient numerical simulation of the internal flow field of the ball valve under the variable speed law and different opening degrees is carried out, and the flow coefficient characteristics, resistance coefficient characteristics, inlet and outlet pressure drop, and internal flow field distribution of the ball valve are analyzed and studied. The results show that by designing the curve function of the ball valve actuator movement process with different structure forms, different types of ball valve flow coefficient and resistance coefficient curve can be obtained, which makes the ball valve as a flow regulating valve more widely used; Modifying the motion law of ball valve electric actuator has little influence on the distribution of ball valve flow field. As long as the motion law of ball valve actuator is optimized within a reasonable range, the purpose of pipeline flow control can be achieved, the inconvenience of valve replacement can be reduced, and the economic cost can be saved.

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.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

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