Research on Open and Close Characteristics of Passive Shuttle-Type Anti-Water-Attack Check Valve

2011 ◽  
Vol 474-476 ◽  
pp. 2290-2295
Author(s):  
Bei Ping Xiang ◽  
Guo Fu Yin ◽  
Xiang Wei Zeng ◽  
Hong Bin Zang
Keyword(s):  
Flow Field ◽  
Rapid Change ◽  
Check Valve ◽  
Pressure Change ◽  
Pipeline System ◽  
Hydraulic Damper ◽  
Pressure Pipeline ◽  
Set Up ◽  
Opening And Closing ◽  
Type Check

Water-attack is very harmful to pressure pipeline system security. Passive shuttle-type anti-water-attack check valve can adjust its open and close time by hydraulic damper, and cushion the rapid change of liquid momentum in order to protect the pumps and pipelines. The structure and working principle of this passive check valve are introduced, and the dynamics model is set up. The opening and closing characteristics of the model is analyzed, and simulation comparison is done between the flow field and pressure change laws of shuttle-type check valve and those of swing check valve. The simulation result shows that the hydraulic damper works very well, the flow field of passive shuttle-type check valve is symmetrical, the forces acting on the shuttle is balanceable, and shuttle-type check valves can replace swing check valves in many fields.

Effects of Valve Disc on Flow Characteristics Inside a Swing Check Valve During Opening and Closing Processes

2021 ◽  
Author(s):  
Yi-xiang Xu ◽  
Qiang Ru ◽  
Huai-yu Yao ◽  
Zhi-jiang Jin ◽  
Jin-yuan Qian
Keyword(s):  
Flow Field ◽  
Working Conditions ◽  
Power Plants ◽  
Flow Characteristics ◽  
Check Valve ◽  
Opening Angle ◽  
Piping System ◽  
Total Moment ◽  
Valve Disc ◽  
Opening And Closing

Abstract The check valve is one of the most important devices for safety protection of the piping system in thermal and nuclear power plants. As the key component of the check valve, the valve disc accounts for a major effect on the flow characteristics especially during the opening and closing processes. In this paper, a typical swing check valve is taken as the research object. In order to make a comparative study, three working conditions of 30% THA (Turbine Heat Acceptance), 50% THA and 100% THA are selected. Focusing on the effects of valve disc, how does the valve disc motion interact with the flow field around the valve disc is analyzed with the help of the dynamic mesh technology. The results show that under the combined action of fluid force and gravity, the check valve can be opened and closed quickly. During the opening process, the maximum total moment of the disc appears between 45° ∼ 50° opening angle, and during the closing process the maximum total moment occurs when the disc fully closed. The flow field near the valve disc has similar variation rules with the rotation of the valve disc in the three working conditions, and the pressure near the valve disc reaches the maximum value at the moment of opening and closing. This study can provide some suggestions for the further optimal design of similar swing check valve.

Study on Temperature Field Characteristic and Temperature Detection of Shuttle-Type High-Temperature, High-Pressure, Anti-Erosion Special Valve

2011 ◽  
Vol 317-319 ◽  
pp. 1277-1281
Author(s):  
Xiu Jun Long ◽  
Gang Jiang ◽  
Xiang Wei Zeng ◽  
Ke Feng Xiang
Keyword(s):  
High Pressure ◽  
Temperature Field ◽  
High Temperature ◽  
Check Valve ◽  
Pipeline System ◽  
Temperature Detection ◽  
Pressure Pipeline ◽  
Pressure Water ◽  
New Type ◽  
High Temperature High Pressure

Check valve is an important fluid control component of pressure pipeline system, shuttle-type high-temperature, high-pressure, anti-erosion special valve is a new type of check valve. The simulation with CFD software Fluent and analysis for its internal temperature field was done, and then make a comparison between Shuttle-type high-temperature, high-pressure, anti-erosion special valve and swing check valve, and it can be concluded that the former doesn't exist local thermal stress concentration. Ultrasonic speed in high-pressure water and steam rely on its temperature, according to this relation, it can be calculate the temperature of fluid in the valve by measuring the transit time of ultrasonic.

Nanoparticle Precipitation in a T-Mixer: Coupling Experimental and Numerical Investigations of the Fluid Dynamics With the Solid Formation Processes

2006 ◽  
Author(s):  
Johannes Gradl ◽  
Florian Schwertfirm ◽  
Hans-Christoph Schwarzer ◽  
Hans-Joachim Schmid ◽  
Michael Manhart ◽  
...  
Keyword(s):  
Flow Field ◽  
Fluid Dynamic ◽  
Concentration Field ◽  
Population Balance ◽  
Mixing Process ◽  
Image Velocimetry ◽  
Modeling Material ◽  
Field Information ◽  
Set Up ◽  
3D Information

Mixing and consequently fluid dynamic is a key parameter to tailor the particle size distribution (PSD) in nanoparticle precipitation. Due to fast and intensive mixing a static T-mixer configuration is capable for synthesizing continuously nanoparticles. The flow and concentration field of the applied mixer is investigated experimentally at different flow rates by Particle Image Velocimetry (PIV) and Laser Induced Fluorescence (LIF). Due to the PIV measurements the flow field in the mixer was characterized qualitatively and the mixing process itself is quantified by the subsequent LIF-measurements. A special feature of the LIF set up is to detect structures in the flow field, which are smaller than the Batchelor length. Thereby a detailed insight into the mixing process in a static T-Mixer is given. In this study a CFD-based approach using Direct Numerical Simulation (DNS) in combination with the solid formation kinetics solving population balance equations (PBE) is applied, using barium sulfate as modeling material. A Lagrangian Particle Tracking strategy is used to couple the flow field information with a micro mixing model and with the classical theory of nucleation. We found that the DNS-PBE approach including macro and micro mixing, combined with the population balance is capable of predicting the full PSD in nanoparticle precipitation for different operating parameters. Additionally to the resulting PSD, this approach delivers a 3D-information about all running subprocesses in the mixer, i.e. supersaturation built-up or nucleation, which is visualized for different process variables.

Evaluation of a Flow Measurement Probe Influence on the Flow Field in High Speed Axial Compressors

2021 ◽  
Author(s):  
Ryosuke Seki ◽  
Satoshi Yamashita ◽  
Ryosuke Mito
Keyword(s):  
Flow Field ◽  
Approximation Method ◽  
High Speed ◽  
Static Pressure ◽  
Axial Compressor ◽  
Pressure Change ◽  
Operating Point ◽  
Blade Row ◽  
Probe Insertion ◽  
Probe Geometry

Abstract The aerodynamic effects of a probe for stage performance evaluation in a high-speed axial compressor are investigated. Regarding the probe measurement accuracy and its aerodynamic effects, the upstream/downstream effects on the probe and probe insertion effects are studied by using an unsteady computational fluid dynamics (CFD) analysis and by verifying in two types of multistage high-speed axial compressor measurements. The probe traverse measurements were conducted at the stator inlet and outlet in each case to evaluate blade row performance quantitatively and its flow field. In the past study, the simple approximation method was carried out which considered only the interference of the probe effect based on the reduction of the mass flow by the probe blockage for the compressor performance, but it did not agree well with the measured results. In order to correctly and quantitatively grasp the mechanism of the flow field when the probe is inserted, the unsteady calculation including the probe geometry was carried out in the present study. Unsteady calculation was performed with a probe inserted completely between the rotor and stator of a 4-stage axial compressor. Since the probe blockage and potential flow field, which mean the pressure change region induced by the probe, change the operating point of the upstream rotor and increase the work of the rotor. Compared the measurement result with probe to a kiel probe setting in the stator leading edge, the total pressure was increased about 2,000Pa at the probe tip. In addition, the developed wake by the probe interferes with the downstream stator row and locally changes the static pressure at the stator exit. To evaluate the probe insertion effect, unsteady calculations with probe at three different immersion heights at the stator downstream in an 8-stage axial compressor are performed. The static pressure value of the probe tip was increased about 3,000Pa in the hub region compared to tip region, this increase corresponds to the measurement trend. On the other hand, the measured wall static pressure showed that there is no drastic change in the radial direction. In addition, when the probe is inserted from the tip to hub region in the measurement, the blockage induced by the probe was increased. As a result, operating point of the stator was locally changed, and the rise of static pressure of the stator increased when the stator incidence changed. These typical results show that unsteady simulations including probe geometry can accurately evaluate the aerodynamic effects of probes in the high-speed axial compressor. Therefore, since the probe will pinpointed and strong affects the practically local flow field in all rotor upstream passage and stator downstream, as for the probe measurement, it is important to pay attention to design the probe diameter, the distance from the blade row, and its relative position to the downstream stator. From the above investigations, a newly simple approximation method which includes the effect of the pressure change evaluation by the probe is proposed, and it is verified in the 4-stage compressor case as an example. In this method, the effects of the distance between the rotor trailing edge (T.E.) and the probe are considered by the theory of the incompressible two-dimensional potential flow. The probe blockage decreases the mass flow rate and changes the operating point of the compressor. The verification results conducted in real compressor indicate that the correct blockage approximation enables designer to estimate aerodynamic effects of the probe correctly.

Oscillating Contractions in Protoplasmic Strands of Physarum: Mechanical and Thermal Methods of Phase Shifting for Studying the Nature of the Synchronizing Factor and its Transmission

1980 ◽  
Vol 85 (1) ◽  
pp. 21-31
Author(s):  
U. ACHENBACH ◽  
K. E. WOHLFARTH-BOTTERMANN
Keyword(s):  
Contractile Activity ◽  
Signal Transmission ◽  
Rapid Change ◽  
Isometric Tension ◽  
The Other ◽  
Rapid Phase ◽  
Thermal Methods ◽  
Original Length ◽  
Set Up ◽  
Rhythmic Contractile Activity

A new experimental investigation chamber was used to analyse the control of rhythmic contractile activity in Physarum. A strand was mounted in such a way that isometric tension measurements of contraction forces could be made on two regions independently, the two regions remaining connected. It was possible to disturb one region experimentally and to compare its behaviour with the other. A short time after being set up in the apparatus, the isometric contraction cycles in the two regions became synchronous. Stretching one region by 50% of its original length induced a phase delay relative to the other. A brief unilateral cold shock (Δt = 5舑15 °C) had a similar phase-retarding effect. Synchrony was subsequently reattained, unless the connecting region was cut or, for example, treated with 30 mM benzamide. In approximately 25% of the investigated strands, a rapid change to a higher temperature (Δt = 2舑5 °C) caused the warmed side to be phase-advanced. However, 75% of the strands did not show a phase shift, suggesting that a rapid phase regulation is supported by increased temperature. The described experimental assay is suitable for analysing the pathway and the nature of signal transmission in plasmodial strands. Note: Partly presented at the International Titisee-Conference on Cellular Oscillators, 22舑24 March 1979 (see J. exp. Biol. (1979)).

The Theoretical Volumetric Displacement of a Check-Valve Type, Digital Displacement Pump

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Noah Manring ◽  
Christopher Williamson
Keyword(s):  
Bulk Modulus ◽  
Flow Rate ◽  
Modulus Of Elasticity ◽  
Check Valve ◽  
Volumetric Flow Rate ◽  
Theoretical Explanation ◽  
Residual Volume ◽  
Displacement Pump ◽  
Opening And Closing ◽  
Piston Chamber

This paper has been written to develop closed-form equations for describing the theoretical displacement of a check-valve type, digital displacement pump. In theory, the digital displacement pump is used to alter the apparent volumetric displacement of the machine by short circuiting the flow path for reciprocating pistons within the machine that would ordinarily deliver a full volumetric flow rate to the discharge side of the pump. The short circuiting for the pistons is achieved by opening and closing a digital valve connected to each piston chamber at a desired time during the kinematic cycle for each reciprocating piston. Experience with these machines has shown that the expected volumetric displacement for the machine tends to decrease with pressure. This paper presents a theoretical explanation for the reduced volumetric displacement of the pump and quantifies the expected behavior based upon the digital valve command, the residual volume of fluid within a single piston chamber, and the fluid bulk modulus-of-elasticity. In summary, it shown that the apparent volumetric displacement of the machine may be reduced by as much as 10% for high-displacement commands and by as much as 30% for low-displacement commands.

Modeling and prediction for the oxidation efficiency of magnesium sulfite in aeration tank of magnesium-based seawater exhaust gas clean system

2017 ◽  
Vol 233 (1) ◽  
pp. 164-173
Author(s):  
Quan Liu ◽  
Yimin Zhu ◽  
Tie Li ◽  
Xiaojia Tang ◽  
Weifeng Liu ◽  
...  
Keyword(s):  
Flow Field ◽  
Initial Conditions ◽  
Negative Impact ◽  
Fluid Model ◽  
Aeration Tank ◽  
Exhaust Gas ◽  
Clean System ◽  
Physics Modeling ◽  
Set Up ◽  
Oxidation Efficiency

In magnesium-based seawater exhaust gas clean system, the desulfurization by-product, magnesium sulfite (MgSO3), has a negative impact on the ecological environment, which needs to be treated to make harmless. Due to the limited space on board, the aeration oxidation method is used to convert it to magnesium sulfate. Because of the variable size, shape and flow field of aeration tank, it is difficult and expensive to design and verify the oxidation efficiency of the aeration tank by experimental method. In this work, in order to predict the oxidation efficiency accurately, RFlow, a computational fluid dynamics software, was used to analyze the flow field and MgSO3 oxidation reaction in aeration tank. The subdomain technology was adopted for physics modeling and mesh generation of the aeration tank, and the total number of meshes was 285,000. The multi-phase flow field model was set up using the multi-fluid model and dispersive k-ε turbulence model. Under the given initial conditions, the predicted oxidation efficiency was 94.2%. Compared with the results of the actual ship test, the prediction model for MgSO3 oxidation efficiency of the aeration tank is reliable.

Designing and Making

Architects ◽  
2019 ◽  
pp. 57-60
Author(s):  
Thomas Yarrow
Keyword(s):  
Rapid Change ◽  
Hard Work ◽  
Narrative Truth ◽  
Design Projects ◽  
Set Up

The office bears the trace of other times and places. As I experienced it in 2014, the room contained ten architects, then involved in the construction of four buildings, with numerous other design projects at various stages of completion. When I visited two years previously, there were still only six architects, working in an office in the house of Tomas’s codirector, Tom, in an extension he had himself designed. The practice had moved there a couple of years before, having outgrown an adapted garden shed at the end of Tomas’s rented cottage. Freezing in winter and too hot in summer, the shed was where they first set up office and where they subsequently took on their first employee. These details are themselves part of a story I hear recounted on a number of occasions. They are factually correct but convey a narrative truth beyond this: of sacrifice, and of rapid change from humble beginnings that is a source collective pride. Alongside this are ambivalences, anxieties that the progress won through hard work has nonetheless been accompanied by changes about which they are more ambivalent....

scholarly journals Air-impingement freezing of peeled shrimp: Analysis of flow field, heat transfer, and freezing time

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983504 ◽  
Author(s):  
Dazhang Yang ◽  
Jing Xie ◽  
Wan Tang ◽  
Jinfeng Wang ◽  
Zhitao Shu
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Field ◽  
Jet Flows ◽  
Freezing Process ◽  
Freezing Time ◽  
Air Jet ◽  
Food Freezing ◽  
Air Impingement ◽  
Set Up

The air-impingement freezing technique is a fast and efficient freezing method, which is widely used in food freezing and electronic industry. A novel air-impingement freezing machine was set up to investigate the food freeze. The freezing process of peeled shrimps by air-impingement freezing technique was studied experimentally and numerically. The freezing time of shrimp (150 count/lb) from +11°C to −18°C was about 100–140 s. The flow field and temperature distribution of peeled shrimp were studied by the solidification and melting model in FLUENT 6.3. The results show that the air jet flows away from the surface of the shrimp after the separation points so that the flow field and heat transfer were bad in the separation resign. In addition, the food freezing time of natural convection and air-impingement was compared, and the result shows that the air-impingement freezing time is about one-tenth than the natural convection freezing in freezer. In order to optimize the air-impingement freezing, H/D’s value was adjusted in the range of 4–8. The result indicates that the freezing time was increasing with the increase in H/D value, and H/D was recommended to be 6 in the impingement freezing.

Modernising the Community Courts

2000 ◽  
Vol 3 ◽  
pp. 37-63 ◽  
Author(s):  
Anthony Arnull
Keyword(s):  
European Union ◽  
Rapid Change ◽  
The European Union ◽  
Member States ◽  
Court Of Justice ◽  
Single European Act ◽  
Set Up ◽  
Court Of First Instance ◽  
Community Courts ◽  
Made In

A purist might say that the judicial architecture of what is now the European Union was first altered by the 1957 Convention on Certain Institutions Common to the European Communities. That Convention set up a single Court of Justice with jurisdiction under the three Community Treaties which had by then been signed. However, the 1957 Convention should probably be regarded as the last brick in the original edifice, which was to remain unchanged for nearly 30 years. Although the Court started to express concern about its capacity to cope with its workload in the 1970s, the Member States did not respond until 1986, when provision for a court of first instance was made in the Single European Act. That reform marked the beginning of a period of rapid change in the judicial architecture of the Union.

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