The Numerical and Experimental Investigation Into Hydraulic Characteristics of a No-Load Running Check Valve due to Fluid-Structure Interaction

2018 ◽  
Author(s):  
Xiang-yuan Zhang ◽  
Zhi-jun Shuai ◽  
Chen-xing Jiang ◽  
Wan-you Li ◽  
Jie Jian
Keyword(s):  
Flow Rate ◽  
Ambient Pressure ◽  
Check Valve ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Pipeline System ◽  
Piping System ◽  
Hydraulic Characteristics ◽  
Mass System ◽  
Excited Vibration

Valve is a very important unit in pipeline system. The valve flow fluctuation brings about structural vibration and unpopular noise, and even leads to the safety problems and disasters. In this paper, a special no-load running check valve is investigated. The check valve is structural complex with one inlet and two outlets. It can be simplified as a spring-mass system which manipulates the flow rate by combine action of the ambient pressure of medium and the spring deformation. The three-dimensional model of the valve is established and also the relationship between pressure drops and flow rate of the valve is obtained in various openings and operating conditions. The structure modals were verified by the field tests and thus its fixing boundaries are obtained correctly. The mechanism causing self-excited vibration of a piping system is determined using a dynamic model which couples the hydraulics of internal flow with the structural motion of a three-ports passive check valve. The coupling is obtained by making the fluid flow coefficient at the check valve to be a function of valve plug displacement. The results are compared with the experimental data, which verifies the correctness of the theoretical results. It is shown that the special valve has its own hydraulic characteristics, which greatly influence its flow distribution as it has two outlets. It was also testified that the coupling between fluid and structure changes its natural frequencies and has a non-negligible impact on the pressure fluctuation while working.

Stabilization of the Speed of the Hydraulic Motor Through Throttle Compensation for Volume Losses

2020 ◽  
Vol 26 (3) ◽  
pp. 126-130
Author(s):  
Krasimir Kalev
Keyword(s):  
Flow Rate ◽  
Hydraulic Drive ◽  
Pressure Change ◽  
Operating Conditions ◽  
Drive System ◽  
Inlet Pressure ◽  
Schematic Diagram ◽  
Hydraulic Characteristics ◽  
Hydraulic Motor ◽  
Flow Through

AbstractA schematic diagram of a hydraulic drive system is provided to stabilize the speed of the working body by compensating for volumetric losses in the hydraulic motor. The diagram shows the inclusion of an originally developed self-adjusting choke whose flow rate in the inlet pressure change range tends to reverse - with increasing pressure the flow through it decreases. Dependent on the hydraulic characteristics of the hydraulic motor and the specific operating conditions.

Control of Self-Excited Oscillations in Centrifugal Blowers

2007 ◽  
Author(s):  
Saad A. Ahmed
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Critical Mass ◽  
Industrial Applications ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Flow Area ◽  
The Stability

Centrifugal compressors or blowers are widely used in many industrial applications. However, the operation of such systems is limited at low-mass flow rates by self-excited flow instabilities which could result in rotating stall or surge of the compressor. These instabilities will limit the flow range in which the compressor or the blower can operate, and will also lower their performance and efficiency. Experimental techniques were used to investigate a model of radial vaneless diffuser at stall and stall-free operating conditions. The speed of the impeller was kept constant, while the mass flow rate was reduced gradually to study the steady and unsteady operating conditions of the compressor. Additional experiments were made to investigate the effects of reducing the exit flow area on the inception of stall. The results indicate that the instability in the diffuser was successfully delayed to a lower flow coefficient when throttle rings were attached to either one or both of the diffuser walls (i.e., to reduce the diffuser exit flow area). The results also showed that an increase of the blockage ratio improves the stability of the system (i.e., the critical mass flow rate could be reduced to 50% of its value without blockage). The results indicate that the throttle rings could be an effective method to control stall in radial diffusers.

Delay of Unsteady Flow in a Radial Diffuser

2008 ◽  
Author(s):  
Saad A. Ahmed
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Flow Instability ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Width Ratio ◽  
Flow Rates ◽  
Lower Flow ◽  
Low Mass

The operation of centrifugal compressor systems is limited at low-mass flow rates by fluid flow instabilities leading to rotating stall or surge. These instabilities limit the flow range in which the compressor can operate. They also lower the performance and efficiency of the compressor. Experiments were conducted to investigate a model of radial vaneless diffuser at stall as well as stall-free operating conditions. The speed of the impeller was kept constant at 2000 RPM, while the mass flow rate was reduced gradually to scan the steady and unsteady operating conditions of the compressor. The flow rate through the compressor was gradually decreased until flow instability is initiated at the diffuser. The flow rate was further reduced to study the characteristics of rotating stall. These measurements were reported for diffuser diameter ratios, Do/Di, of 2.0 with diffuser width ratio, b/Di, of 0.055. At lower flow rates than the critical, the rotating stall pattern with one stall cell was dominant over the pattern with two cells. In addition, the instability in the diffuser was successfully delayed to a lower flow coefficient when rough surfaces were attached to one or both sides of the diffuser with the lowest values achieved by attaching the rough surface to the shroud. Results show that the roughness has no significant effect on stall cell characteristics.

NON-DIMENSIONAL DISTRIBUTION PATTERN ANALYSIS OF PARTICLE TRANSPORTATION IN SIMPLIFIED PIPELINE SYSTEM

2015 ◽  
Vol 77 (12) ◽  
Author(s):  
Mohd Zamani Ngali ◽  
Kahar Osman ◽  
Nazri Huzaimi Zakaria
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Flow Behavior ◽  
Solid Sphere ◽  
Rate Variation ◽  
Pipeline System ◽  
Piping System ◽  
Weight Variation ◽  
Dimensional Simulation ◽  
Particle Weight

Sustainable preservation of pipeline system that deal with particle transportation is more appealing these days. In petroleum industries for instance, sand transported through the pipelines pose serious problems ranging from blockage, corrosion, abrasion and reduction in pipe efficiency to loss of pipe integrity. Accurate four-dimensional simulation that caters the transient effect of the phenomena is used to promote sustainability in design, evaluation and maintenance procedures. This is employed to minimize conventional practices which are costly and inefficient. This work demonstrates the advantages of applying four-dimensional Splitting Fluid-Particle Solver to simulate particle transportation within a simplified pipeline system. Single-phase fluid with solid sphere particles are the assumptions while drift and gravitational forces are taken into account. Effect of fluid flow rate and particle weight alterations are observed within vertical curled and 2-1-2 segmental pipeline. Flow rate variation on multiple inputs shows that proper simulation is essential in order to predict fluid flow behavior prior to pipeline construction. Particle weight variation shows that simulation can lead to better prediction of potential areas of blockage, corrosion, abrasion and other piping system issues. This work proves that four-dimensional simulation can promote sustainability, cost effectiveness and efficiency of pipeline system management. 

Fluid Transient Responses With Check Valves in Pipe Flow System With Air Entrainment

1997 ◽  
Author(s):  
T. S. Lee ◽  
L. C. Leow
Keyword(s):  
Transient Flow ◽  
Flow System ◽  
Check Valve ◽  
Air Entrainment ◽  
Pipeline System ◽  
Piping System ◽  
Transient Responses ◽  
Fluid System ◽  
Free System ◽  
Fluid Transient

A common flow system arrangement in piping system consists of a lower reservoir, a group of pumps with a check valve in each branch, and a pipeline discharging into a upper reservoir. In earlier studies of check valves performances in transient flow, none considered the effects of air entrainment into a pipeline system and the subsequent effects on the check valve performances in transient flow. Studies on pressure surges during pump tripped in pumping systems showed that by including an air entrainment variable wave speed model, reasonable predictions of fluid transient responses with proper phasing and attenuation of pressure peaks can be obtained. The most severe case where all the pumps in the station fail simultaneously due to power failure was analysed for their maximum and minimum pressure variation along the pipeline. A numerical model is now set up in the present work to investigate the check valve performances in transient flow for a pumping system with air entrainment. The analyses examine a fluid system with a variable air entrainment content (ε) and studied numerically it effects on the flow reversal time and hence determine the appropriate valve selection for a given fluid system to minimize problems of check valve slamming. Present numerical computations show that the air content in a fluid system can adversely affect the check valve transient responses. With the fluid system operating within a critical range of air entrainment values, analysis showed that there is a possibility of “check valve slamming” when the check valves were selected based on the analysis of an air free system. The above phenomena is confirmed through physical field measurements.

scholarly journals THEORETICAL ANALYSIS AND GRAPHICAL REPRESENTATION OF THE SYSTEM CURVE FOR WATER PIPELINE CONNECTING ZAWIA DESALINATION PLANT WITH HARSHA TANKS

2019 ◽  
Vol 2 (1) ◽  
pp. 38-51
Author(s):  
Abdulmenam A. Abdalla ◽  
Ali K. Muftah ◽  
Ahmed O. Amhamed
Keyword(s):  
Flow Rate ◽  
Graphical Representation ◽  
Water Levels ◽  
Pipeline System ◽  
Piping System ◽  
Performance Curve ◽  
Desalination Plant ◽  
System Flow ◽  
Water Pipeline ◽  
The Right

The flow of water within a pipeline system causes loss of energy due to friction effects. To overcome these losses, energy is added to the water through the pump. So, the right pump selection is important for providing the required flow rate. The first step to select a right pump for any pipeline system is calculating the performance curve of piping system, which is a graphical representation of the energy required to move a given flow rate through a piping system and is used to identify the characteristics of the system's pump. For this purpose, the system curve for the water pipeline connecting the main reservoirs of Zawia desalination plant to the sub-tanks in Harsha has been evaluated and represented graphically in H-Q curve of the selected pump. This water pipeline network consists of sets of pipes connected in parallel and series with a total length of 5 km. The system NPSHA at different water levels in the suction tank at the maximum system flow rate of 800 (m3/hr) has been calculated to ensure avoiding cavitations problem in the selected pump.

scholarly journals Dynamics of the nozzle valve with regard to the properties of the piping system

2018 ◽  
Vol 180 ◽  
pp. 02043
Author(s):  
Roman Klas ◽  
Vladimír Habán ◽  
Pavel Rudolf
Keyword(s):  
Dynamic Properties ◽  
Equations Of Motion ◽  
Operating Conditions ◽  
Pipeline System ◽  
Piping System ◽  
Main Function ◽  
Pressure Pulsations ◽  
Cfd Simulations ◽  
Valve Disc ◽  
Pipeline Model

It is obvious that the main function of the nozzle valve is to shut off the stream of fluid in the piping system. The response rate of the valve to the decreasing or reversing flow in the system will then depend on the valve properties and equally on the properties of the piping system. The interaction of these two elements is also important for the origin of pressure pulsations in the system. While the pressure pulsations were the cause for design of this particular valve it should be noted that the general design of the valve for any pipeline system is not possible. The valve cannot properly work under all circumstances and operating conditions. With respect to this, the dynamic properties of the valve will be assessed on the basis of the valve equation of motion and the pipeline model. An adequate response of the whole system can be obtained by combining both approaches. The valve equations of motion are also complemented by CFD simulations, which enable to capture the movement of the valve disc with respect to flow rate.

scholarly journals Test of measurement device for the estimation of leakage flow rate in pneumatic pipeline systems

2018 ◽  
Vol 51 (9-10) ◽  
pp. 514-527
Author(s):  
Ryszard Dindorf ◽  
Piotr Wos
Keyword(s):  
Flow Rate ◽  
Compressed Air ◽  
Measuring System ◽  
Pipeline System ◽  
Piping System ◽  
Leakage Flow ◽  
Automatic Measuring ◽  
Measurement Device ◽  
Leakage Flow Rate ◽  
Leak Testing

Background: Indirect measurements of flow rate serve to determine air consumption, leakage values and characteristics of compressed air systems (CASs). Method: A new method of indirect flow rate measurement in a pneumatic pipeline system was developed. The method enables to measure the controlled leakage in a branch line and was used to construct automatic measuring systems auditing the compressed air systems piping. Results: First, the leak-testing instrument LT-I 200 was designed, constructed, and tested as portable measurement device for the estimation of air leakage flow rate in pneumatic pipeline system. Next, based on the authors’ patent, the automatic measuring system for the measurement of the leakage flow rate in industrial compressed air piping was developed. Conclusion: The measurement device was used to estimate of the leakage flow rate and cost of the energy losses in the compressed air piping system.

Acoustic and Vibration Analysis of Fluid Induced Blower and Piping Unwanted Motion

2011 ◽  
Author(s):  
Ned M. Endres
Keyword(s):  
Sound Pressure ◽  
Check Valve ◽  
Operating Conditions ◽  
Piping System ◽  
Vibration Measurements ◽  
System A ◽  
Sound Levels ◽  
Sound Pressure Levels ◽  
Air Blower ◽  
High Sound

This paper presents investigational findings and a discussion of recommendations relating to sound and vibration measurements performed in connection with a fluid induced vibration issue on two air blowers and attached exhaust piping at an industrial facility. These vibration and sound measurements were prompted by recent check valve failures for the air blower units, and unacceptable sound levels emanating from these units and affecting nearby residents. This data was acquired during steady state operating conditions of the blowers under normal operating conditions. An FFT data acquisition system, a piezoelectric microphone and three piezoelectric triaxial accelerometers were used to collect vibration measurements at each of the 70 locations on the blowers, motors, blower bases, and exhaust piping, while sound measurements were simultaneously acquired with the microphone. Piping and blower vibration readings were used to construct an operating deflection shape analysis of the blowers, foundations and attached piping system. The resulting vibration and sound analysis revealed that acoustic excitation of the piping system appeared to be the likely source of the high vibration, high sound pressure levels; piping cracks and check valve failures. Corrective actions were implemented that reduced the sound pressure levels, vibration levels, and reduced/eliminate the piping damage and valve failures.

scholarly journals Chemical–Electrochemical Process Concept for Lead Recovery from Waste Cathode Ray Tube Glass

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1546
Author(s):  
Árpád Imre-Lucaci ◽  
Melinda Fogarasi ◽  
Florica Imre-Lucaci ◽  
Szabolcs Fogarasi
Keyword(s):  
Flow Rate ◽  
Current Density ◽  
Complete Recovery ◽  
Electrochemical Process ◽  
Operating Conditions ◽  
General Effect ◽  
Optimal Operating ◽  
Recirculation Flow ◽  
Lead Recovery ◽  
Cathode Ray Tube

This paper presents a novel approach for the recovery of lead from waste cathode-ray tube (CRT) glass by applying a combined chemical-electrochemical process which allows the simultaneous recovery of Pb from waste CRT glass and electrochemical regeneration of the leaching agent. The optimal operating conditions were identified based on the influence of leaching agent concentration, recirculation flow rate and current density on the main technical performance indicators. The experimental results demonstrate that the process is the most efficient at 0.6 M acetic acid concentration, flow rate of 45 mL/min and current density of 4 mA/cm2. The mass balance data corresponding to the recycling of 10 kg/h waste CRT glass in the identified optimal operating conditions was used for the environmental assessment of the process. The General Effect Indices (GEIs), obtained through the Biwer Heinzle method for the input and output streams of the process, indicate that the developed recovery process not only achieve a complete recovery of lead but it is eco-friendly as well.

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