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Thursday, November 5, 2020 | History

2 edition of Swirl and vortices at intakes. found in the catalog.

Swirl and vortices at intakes.

G. A. J. Young

Swirl and vortices at intakes.

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Published by British Hydromechanics Research Association in [s.l.] .
Written in English


Edition Notes

SeriesBHRA specialpaper -- 726
ContributionsBHRA.
ID Numbers
Open LibraryOL20904604M

and it should be without swirl, vortices, and entrained air: • Non-uniform flow at the pump intake can reduce efficiency, cause pulsating loads, and produce both noise and vibrations. • Vortices emanating from the free surface can become strong enough to draw air and floating debris into the pump.


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Swirl and vortices at intakes. by G. A. J. Young Download PDF EPUB FB2

Book Description. Fundamentals of vortex intake flow; Results theoretical & experimental work; Prediction of critical submergence; Modeling of vortices & swirling flows; Design; Intake structures; Pump sumps; Vortex-flow intakes.

This volume forms an essential reference work for anyone involved in intakes, either as a practising design engineer or research worker. COVID Resources. Reliable information about the coronavirus (COVID) is available from the World Health Organization (current situation, international travel).Numerous and frequently-updated resource results are available from this ’s WebJunction has pulled together information and resources to assist library staff as they consider how to handle coronavirus.

Fundamentals of vortex intake flow; Results theoretical & experimental Swirl and vortices at intakes. book Prediction of critical submergence; Modeling of Swirl and vortices at intakes.

book & swirling flows; Design; Intake structures; Pump sumps; Vortex-flow intakes. This volume forms an essential reference work for anyone involved in intakes, either as a practising design engineer or research worker. Water Power & Dam Constr., July The book Cited by: Swirling Flow Problems at Intakes book.

Swirling Flow Problems at Intakes. Stable vortices are characterized by a steady production of swirl in the approach flow field. Regarding the entrained swirl, with otherwise equal conditions the indicated swirl angle is independent of the flow rate and also independent of the occurrence of air.

Catalogue description The prevention of vortices and swirl at intakes D F Denny and G A J Young This record is closed whilst access is under review Submit FOI request; This record is closed and cannot be viewed or reproduced as a digital or printed copy.

You can submit a. Keywords: pump intakes, vortices, deflector beam, vane turning box, submergence, swirl angle, pre-rotation, horizontal flow. 1 Introduction The criteria suggested for effective pump operation entail, the limitation of surface vortices, ensuring a balanced velocity distribution and limiting the prerotation at.

from ref [4], to evaluate the strength of vortices at pump intakes systematically, the vortex scale varying from surface swirl or dimple to an air core vortex, as shown in figure 1. Sometimes an. Pump intake structure design is one area where physical models still remain as the only acceptable method that can provide reliable engineering results.

Ensuring the amount of turbulence, entrained air vortices, and swirl are kept within acceptable limits requires site-specific, expensive, and time-consuming physical model studies.

This study aims to investigate the viability of Computational. A common challenge faced by engineers in the hydraulic industry is the formation of free surface vortices at pump and power intakes.

This undesirable phenomenon which sometimes entrains air could result in several operational problems: noise, vibration, cavitation, surging, structural damage to turbines and pumps, energy losses, efficiency losses, etc.

This paper investigates the numerical. intake divided by the conduit diameter has also been used as a uniform approach of evaluating vortices (Reddy and Pickford, ).

Classification of vortices is qualitative, but research by Durgin and Anderson resulted in a map of vortex types that correspond to the strength of the vortex (Durgin and Anderson, ). Vortex flow in a pump intake could affect a pump operation significantly if not treated appropriately.

Many researches have been conducted to determine the best control method for vortex flow in pump sumps so that the pump lifespan can be maximized. In this study, a vortex control principle designed to minimize the impact of submerged vortex flow in pump sump on major pump components. Journals & Books; Help Download PDF Hydraulic model studies can be used to gain an understanding of the formation of intake vortices and thus aid decision-making on the optimal solution to suppress the vortices: G.H.J.

YoungThe prevention of vortices and swirl at intakes. Proceedings of 7th IAHR Congress, 1, Lisbon () CC For a vertically downward flowing intake, critical submergence is defined as the vertical distance between the intake center and water surface level when air just enters the intake by a free-surface vortex.

However, for a horizontally flowing intake air enters the intake at the summit point of the intake. Swirling flow in the pump sump and/or intake is linked to intake structures susceptible to vortex formation. Swirling flow and the formation of vortices at the intakes have negative effects on pumps in the intake structure.

water in the pump sump to the top most point of intake required to prevent air entraining vortices (see Fig.

Critical Submergence for Vertical Intakes It is the minimum depth from the water surface to the pump intake to prevent entry of air and formation of vortices.

“The prevention of vortices and swirl at intakes.” Proc. of 7th IAHR Congress, Vol. 1, International Association for Hydro-Environmental Engineering and Research (IAHR), Lisbon, C–C.

We observed two distinct vortex structures: a single-celled vortex at the lowest swirl ratio (S =θv = 15°) and multiple suction vortices rotating around the primary vortex (two-celled.

N2 - This paper presents the results of an experimental investigation designed to predict the formation of weak, free-surface vortices at vertical intakes with a headrace channel. A weak vortex is defined as a coherent, persistent dye core into the intake, the vortex classification to be avoided at pump and turbine intakes.

"This thesis presents a series of physical experiments and numerical simulations intended to determine whether the use of commercially available computational fluid dynamics (CFD) software may provide a viable alternative to the use of physical models for predicting the occurrence of vortices and swirl in pump intakes.

The physical experiments were set up at Alden Research Laboratories, Inc. Vortices have their origin in swirling flow, which form at the hydraulic intake structure due to their location relative to surrounding boundaries and geometric properties.

In simple word, a swirl is a tendency of water at the intake to move with twisting or whirling motion. The swirl motion itself in not an engineering problem.

Surface swirl stage [Figs. 3(a) and 4(a)]. Weak swirls appear on the free surface above the pipe intake. As shown in Sectionvortices near the free surface are convected by the mean flow towards the region above the pipe intake, where the vortices are stretched and amplified (Section ).

The tips of these surface vortices are observed to. This paper presents the results of an experimental investigation into the hydraulic efficiency of a vertically oriented water intake.

Under low submergence conditions, the operation of such an intake is affected significantly by the formation of surface vortices, which result in significant flow reduction and the downstream entrainment of air and swirl. In addition, proximity of the intake to the reservoir abutments and the dam body affects the strength of vortices.

Recently, Sarkardeh et al. showed the effect of intake head wall slope on vortex type and strength. These facts reveal that the strength of vortices is a case-dependent phenomenon and varies from reservoir to reservoir.

Three-dimensional Computational Fluid Dynamics model solved the Unsteady Reynolds-Averaged Navier–Stokes equations for predicting the occurrence of vortices and swirl in pump intakes. In this study, three different modifications were done.

The research shows that existing circular sump shape generates swirl flow. The vortices were reduced by making the end wall vertical and moving it closer to the pump. The best distance is the least distance, but D/4 is, perhaps, the best practical clearance. Vortices can also be reduced or eliminated by increasing the submergence of the intake.

Comparison of the Effects of Intake-Generated Swirl and Tumble on Turbulence Characteristics in a 4-Valve Engine An experimental investigation is carried out on the effect of Swirl and Tumble on turbulence and combustion characteristics in four-valve spark ignition engines.

full air core to intake) was also observed clearly in ANSYS CFX. Keywords: Pump sump • Free surface vortices • Swirl angle • Computational fluid dynamics (CFD) 1. Introduction A pump sump or intake is simply defined as a hydraulic structure with specific dimensions used to contain the water which has to be pumped into the piping system.

@article{osti_, title = {Comparison of the effects of intake-generated swirl and tumble on turbulence characteristics in a 4-valve engine}, author = {Floch, A and Frank, J Van and Ahmed, A}, abstractNote = {An experimental investigation is carried out on the effect of Swirl and Tumble on turbulence and combustion characteristics in four-valve spark ignition engines.

Intakes of large pump stations are often designed with the aid of hydraulic modeling. The approach flow to pumps is tested for adverse hydraulic phenomena, such as pre-swirl, velocity variations and vortices. Most commonly, the limits for these phenomena are taken from the ANSI/HI standard - Rotodynamic Pumps for Pump Intake Design.

The first chapter (by J. Knauss) discusses the sources of swirl and vortex formation, the classification of intakes and — most importantly — the classification of vortices by location and strength from weak (surface dimple) to a strong developed vortex with an open air core.

Finally it lists swirling. Velocity-induced vortices are common occurrences at hydraulic intakes and are detrimental to the operation and efficiency of hydraulic structures. Velocity-induced vortices also form in physical hydraulic models and although Froude scaling principles account for initial and gravity forces, the scale effects associated with vortices in Froude are less certain.

Part of the Lecture Notes in Mechanical Engineering book series (LNME) Abstract. Non-uniform flow caused due to a vortex in the pump intake is considered undesirable for highly efficient and low maintenance operation. The Prevention of Vortices and Swirl at Intakes. and Patel, V.: Numerical Model for Simulation of Pump-Intake Flow and.

pump intake. Thus, the determination of the critical submergence is a safety relevant matter for the design of pump intakes. Therefore, a test facility was built at the Hamburg University of Technology which pro-vides experimental data on the shape of surface vortices in vertical vessels and strongly rotating flow.

); prediction of vortices, swirl angle, velocity distribution and air entrainment. With regards to the prediction of vortices in the wet well, the applied CFD models perform well. However, the effectiveness of the models to capture velocity distribution and highly swirling flows at pump intakes is debatable.

solution for avoiding air-entrainment and swirl is to provide su cient submergence to the intake. If the required approach ow conditions cannot be met to avoid swirl and air entrainment, it is economical to consider other approaches for preventing vortices at water intakes.

While the e ect of extreme pressure 1. Department of Civil Engineering. Using a scale laboratory model, the performance of the proposed pump-intake and cooled-water discharge flume was evaluated for the Florida Power Corporation's Crystal River Units 1, 2, and 3 helper cooling-tower project.

Nonuniform pump-approach flow distributions were rectified by means of arrays of baffle blocks; subsurface vortices were. In the present study it was utilized Taylor vortex flow of water in a hot water and the air swirl flow of cold fluid inside counter heat exchanger designed for this purpose.

It was generating Taylor vortices by hot water at 80 °C inside annular space between overlapping cylinder. Intake Structure into Tunnel Model of Ship Repair Yard Strong Air Entraining Vortices at Low Water Level Spillway Model Splitter to Reduce Submerged Vortices and Swirl.

Energy Dissipation in Flood Tunnel by an Upstand Intake to Flood Tunnel. The results clearly show that the entrainment envelope for swirling flow is several times larger than that for non-swirling flow.

This paper details, for a given set of conditions, the differences in the non-swirling and swirling flow entrainment envelopes and emphasizes the potential difficulties with frazil ice that vortices can cause at intakes. The purpose of this paper is to characterise barrel swirl behaviour in a production four-valve engine with pentroof chamber.

Steady flow analysis showed that the insertion of tubes into the cylinder head's induction tracts increased the tumbling ratio of the in-cylinder flow field at intake valve closure. The O.N.

Stevens pump station in Corpus Christi, Texas, was originally designed in the mids. The pump station is configured with the two pump buildings connected to two common discharge lines. IMAGE 1: Plan and section of O.N.

Stevens Nueces River intake (Images courtesy of LAN) The original pumping station, located in pump building 1, was planned with several design deficiencies.Engine experiment was performed at 2, 2, 3, 3, 4, 4, and 5, rpm engine speed at WOT using a concave swirl type generator.

Response Surface method (RSM) was used to find the optimum intake manifold design according to response (flow and swirl) and independent variables (a type of swirl generators and angle positions).When a person moves, a force is applied in that direction.

As a result a flow occurs. When a fast flow occurs a rotation phenomenon is produced due to the difference in the flow velocity around it, creating a in the artwork is expressed as a continuum of numerous particles and the interaction between the particles is calculated.

Lines are drawn according to the trails of the.