Structural design and parameter optimization on a waste valve for hydraulic ram pumps

2020 ◽  
pp. 095765092096748
Author(s):  
Jiazhen Li ◽  
Kailin Yang ◽  
Xinlei Guo ◽  
Wei Huang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Potential Energy ◽  
Check Valve ◽  
Flow Passage ◽  
Future Design ◽  
Head Loss Coefficient ◽  
Valve Disc ◽  
Low Head ◽  
Valve Opening ◽  
High Head ◽  
Major Factors

Hydraulic ram pump is an automatic water-lifting machinery, which converts the low-head potential energy of a large volume of water into a small high-head potential energy through the periodic open and close of waste valve and delivery valve. The pump would run inefficiently or even fail if the valves are poorly designed. In this paper, a novel and reliable waste valve of lift-check-valve structure has been developed. The sealing mode integrating soft and rigid sealing rings, the equation for the valve disc thickness and the equation for the flow passage in terms of the diffuser length, the larger radius and the smaller radius, are presented to guide future design. Major factors influencing the hydraulic performance, including the flow passage, valve opening and valve clack mass, are discussed with model experiments and numerical simulations. The optimized configuration for a 100-mm hydraulic ram pump includes a curved diffuser, 25–30-mm valve opening and 1.2-kg valve clack mass. The proposed waste valve can decrease the head loss coefficient of the system by 45%, achieve relatively higher working efficiency, and lift the largest water when the delivery head is lower than 30 m.

scholarly journals Comparison of Swing and Tilting Check Valves Flowing Compressible Fluids

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 758
Author(s):  
Zhi-xin Gao ◽  
Ping Liu ◽  
Yang Yue ◽  
Jun-ye Li ◽  
Hui Wu
Keyword(s):  
Mach Number ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Check Valve ◽  
Small Mass ◽  
Working Fluid ◽  
Valve Disc ◽  
Valve Opening ◽  
The Difference

Although check valves have attracted a lot of attention, work has rarely been completed done when there is a compressible working fluid. In this paper, the swing check valve and the tilting check valve flowing high-temperature compressible water vapor are compared. The maximum Mach number under small valve openings, the dynamic opening time, and the hydrodynamic moment acting on the valve disc are chosen to evaluate the difference between the two types of check valves. Results show that the maximum Mach number increases with the decrease in the valve opening and the increase in the mass flow rate, and the Mach number and the pressure difference in the tilting check valve are higher. In the swing check valve, the hydrodynamic moment is higher and the valve opening time is shorter. Furthermore, the valve disc is more stable for the swing check valve, and there is a periodical oscillation of the valve disc in the tilting check valve under a small mass flow rate.

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.

Paddlefish: Ecological, Aquacultural, and Regulatory Challenges of Managing a Global Resource

2019 ◽  
Keyword(s):  
Habitat Restoration ◽  
Local Level ◽  
High Speeds ◽  
The Status ◽  
Low Head ◽  
Management Techniques ◽  
High Head ◽  
Elevated Rate ◽  
Access And Quality

<i>Abstract</i>.—Paddlefish <i>Polyodon spathula</i> are behaviorally, morphologically, and physiologically adapted for prolonged free-swimming at moderately high speeds but not for maneuverability which makes them prone to impacts from submerged structures. These structures include low-head dams, weirs, dikes, levees, high-head dams, dredges, diversions, intakes, and vessels. Impacts include blocked migrations, reduced access and quality of habitat, entrainment, impingement, trauma, and stranding. Effects of these impacts on individuals are displacement, injuries, and death; effects on populations are fragmentation, lower gene flow, lower reproductive success, and elevated rate of mortality. Despite this, the status of the Paddlefish in most parts of its historic range is secure. Management techniques, like stocking and habitat restoration, are typically implemented at the local level but appear effective at conserving the species range wide. Refinement of management techniques, however, is still possible by modifying operations of structures and by rescuing stranded Paddlefish.

scholarly journals Study of the nozzle check valve with respect to its operating characteristics

2018 ◽  
Vol 180 ◽  
pp. 02044 ◽  
Author(s):  
Roman Klas ◽  
Vladimír Habán ◽  
Pavel Rudolf
Keyword(s):  
Cfd Simulation ◽  
Check Valve ◽  
Operating Characteristics ◽  
Valve Design ◽  
Pressure Fields ◽  
Valve Disc ◽  
Unsteady Operation ◽  
Simulation Results ◽  
2D And 3D ◽  
Main Operating

Several modifications were developed when designing the nozzle valve. This study offers an assessment of the properties of new modifications of the nozzle valve design. The main operating characteristics, such as loss and flow coefficients, were determined using a CFD methods. Besides mentioned coefficients, the forces acting on the valve disc are also decisive for the behavior of the valve, both in its steady and unsteady operation. It is important to examine the possible simplification and matching of CFD simulation results from 2D and 3D geometries in terms of subsequent dynamic analysis of the valve. This will be taken into consideration by comparing the above-mentioned operating characteristics, by analyzing the forces acting on the valve disc and comparing the velocity and pressure fields.

scholarly journals Holistic Design Approach of a Throttled Surge Tank: The Case of Refurbishment of Gondo High-Head Power Plant in Switzerland

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3440
Author(s):  
Mona Seyfeddine ◽  
Samuel Vorlet ◽  
Nicolas Adam ◽  
Giovanni De Cesare
Keyword(s):  
Power Plant ◽  
Transient Flow ◽  
Holistic Approach ◽  
Head Loss ◽  
Surge Tank ◽  
3D Numerical Modeling ◽  
Head Loss Coefficient ◽  
Loss Coefficients ◽  
High Head ◽  
Modeling Strategy

In order to increase the installed capacity, the refurbishment of Gondo high-head power plant required a modification of the existing surge tank by installing a throttle at its entrance. In a previous study, the geometry of this throttle was optimized by physical modeling to achieve the target loss coefficients as identified by a transient 1D numerical analysis. This study complements previous analyses by means of 3D numerical modeling using the commercial software ANSYS-CFX 19 R1. Results show that: (i) a 3D computational fluid dynamics (CFD) model predicts sufficiently accurate local head loss coefficients that agree closely with the findings of the physical model; (ii) in contrast to a standard surge tank, the presence of an internal gallery in the surge tank proved to be of insignificant effect on a surge tank equipped with a throttle, as the variations in the section of the tank cause negligible local losses compared to the ones induced by the throttle; (iii) CFD investigations of transient flow regimes revealed that the head loss coefficient of the throttle only varies for flow ratios below 20% of the total flow in the system, without significantly affecting the conclusions of the 1D transient analysis with respect to minimum and maximum water level in the surge tank as well as pressure peaks below the surge tank. This study highlights the importance of examining the characteristics of a hydraulic system from a holistic approach involving hybrid modeling (1D, 3D numerical and physical) backed by calibration as well as validation with in-situ measurements. This results in a more rapid and economic design of throttled surge tanks that makes full use of the advantages associated with each modeling strategy.

The Operating Condition Estimation of the Equipment in Decision-Making Process in the Hydro Power Plant Control

2014 ◽  
Vol 698 ◽  
pp. 785-789
Author(s):  
Yana Panova ◽  
Vladimir Derbenev ◽  
Anastasiya Zhdanovich
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Hydroelectric Power ◽  
Operational Control ◽  
Hydro Power ◽  
Operating Condition ◽  
Power Plant Control ◽  
Low Head ◽  
High Head ◽  
Sets Theory

This article is devoted to the principles of constructing the decision support information system at the hydroelectric power plants. It’s assumed that the fuzzy sets theory will be used for the representation of the information about the aggregates operating condition parameters. The paper reflects the advantages of such an approach. The calculations were done for the equipment of the low-head (Novosibirskaya HPP, Hydro Power Plant) and high-head (Sayano–Shushenskaya HPP) power plants. The results obtained are intended for solving the HPPs operational control problems.

Flow Induced Vibrations of a Hydraulic Valve and Their Elimination

1978 ◽  
Vol 100 (2) ◽  
pp. 239-245 ◽  
Author(s):  
D. S. Weaver ◽  
F. A. Adubi ◽  
N. Kouwen
Keyword(s):  
Check Valve ◽  
Rate Of Change ◽  
High Rate ◽  
Fluid Inertia ◽  
Dimensional Model ◽  
Flow Control Devices ◽  
Flow Induced Vibrations ◽  
Valve Opening ◽  
Control Devices ◽  
Hydraulic Valve

The flow induced vibrations of a check valve with a spring damper to prevent slamming have been studied experimentally. Both prototype and two-dimensional model experiments were conducted to develop an understanding of the mechanism of self-excitation. The phenomenon is shown to be caused by the high rate of change of discharge at small angles of valve opening and the hysteretic hydrodynamic loading resulting from fluid inertia. As the discharge-displacement characteristics of the valve are dependent on its geometry, modifications of this geometry were examined and one found which eliminated the vibrations entirely. The phenomenon studied is considered to be the same as that causing vibrations in numerous other flow control devices when operating at small openings.

scholarly journals A Study on Developing Pico Propeller Turbine for Low Head Micro Hydropower Plants in Nepal

2014 ◽  
Vol 9 (1) ◽  
pp. 36-53 ◽  
Author(s):  
Pradhumna Adhikari ◽  
Umesh Budhathoki ◽  
Shiva Raj Timilsina ◽  
Saurav Manandhar ◽  
Tri Ratna Bajracharya
Keyword(s):  
Cross Flow ◽  
Design Flow ◽  
Constant Thickness ◽  
Manufacturing Cost ◽  
Scaling Effects ◽  
Speed Increase ◽  
Hilly Region ◽  
Low Head ◽  
High Head ◽  
Airfoil Blades

Most of the turbines used in Nepal are medium or high head turbines. These types of turbines are efficient but limited for rivers and streams in the mountain and hilly region which have considerably high head. Low head turbines should be used in the plain region if energy is to be extracted from the water sources there. This helps in the rural electrification and decentralized units in community, reducing the cost of construction of national grid and also to its dependency, in already aggravated crisis situation. There are good turbine designs for medium to high heads but traditional designs for heads under about 5m (i.e. cross flow turbine and waterwheel) are slow running, requiring substantial speed increase to drive an AC generator. Propeller turbines have a higher running speed but the airfoil blades are normally too complicated for micro hydro installations. Therefore, the open volute propeller turbine with constant thickness blades was ventured as possible solution. Such type of propeller turbine is designed to operate at low inlet head and high suction head. This enables the exclusion of closed spiral casing. Also, the constant thickness blades enable the use of forging process instead of casting of complex airfoil blades. This leads to considerable reduction in manufacturing cost and complexity. A 1kW prototype was designed and scale down model of 185W was fabricated and tested. The runner consisted of five blades of 4mm thickness with camber and twist. The runaway speed of 1058 rpm was attained at design flow rate of 25 l/s. At full load the efficiency of model was found to be about 57%. Applying scaling effects the expected efficiency of the prototype was estimated to be about 60%. DOI: http://dx.doi.org/10.3126/jie.v9i1.10669   Journal of the Institute of Engineering, Vol. 9, No. 1, pp. 36–53

scholarly journals Characteristic analysis of the efficiency hill chart of Francis turbine for different water heads

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769007 ◽  
Author(s):  
Pengcheng Guo ◽  
Zhaoning Wang ◽  
Longgang Sun ◽  
Xingqi Luo
Keyword(s):  
Incidence Angle ◽  
Suction Side ◽  
Francis Turbine ◽  
Small Range ◽  
Characteristic Analysis ◽  
Wide Range ◽  
Low Head ◽  
Model Efficiency ◽  
Hydraulic Turbines ◽  
High Head

According to several model test results of Francis turbines, complete model efficiency hill charts were constructed. The formation and inevitability of diversified hydraulic phenomena on model efficiency hill chart for typical head range were analyzed and the difference is compared, as well as characteristics and commonness toward the curves are discussed and summarized. Furthermore, hydraulic performance and geometric features are presented by particularly analyzing the efficiency hill charts. The inherent characteristics of Francis turbine is expressed by all kinds of curves on the model efficiency hill charts, and these curves can be adjusted and moved in a small range but cannot be removed out. Due to wide range of unit speed in terms of medium-low-head hydraulic turbines, incipient cavitation curve on suction side can be observed and it is positioned close to the operation zone; however, it fails to be visualized for the high-head turbine. The blade channel vortex curves are in the vicinity of optimum region for low-head hydraulic turbines, while high-head shows reverse trend. The interaction between zero incidence angle and zero circulation curve has a significant influence on isoefficiency circles. All comparisons and analyses could provide hydraulic design basis and retrofit references.

Fault Diagnosis of Reciprocating Compressor Valve Using Acoustic Emission

2012 ◽  
Author(s):  
Y. F. Wang ◽  
X. Y. Peng
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emission Signal ◽  
Reciprocating Compressor ◽  
Flow Passage ◽  
Emission Signal ◽  
Fault Features ◽  
Discharge Valve ◽  
Valve Disc ◽  
Deviation Degree ◽  
Discharge Pressure

The faults of a reciprocating compressor valve can be diagnosed using the acoustic emission. Four typical valve faults including the crack, rupture and deformation in the valve discs and leakage through the flow passage were investigated. The fault features were extracted by comparing the acoustic emission signals from the failed valves with those from the normal valves. The results show that the feature locations where the discharge valve opened and closed could easily be identified by the envelope waveform of acoustic emission signal, and they changed when the valve failed including the rupture and deformation in valve discs and leakage through the flow passage and changed with the variation of the discharge pressure. The extent to which the valve failed could be estimated by the deviation degree between the opening/closing locations and the standard ones. The leakage caused by these valve faults could also lead to the increase in the amplitude of the acoustic emission wave. However, the fault of crack in valve disc couldn’t be identified by acoustic emission signal effectively.

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