EXPERIMENTAL INVESTIGATION INTO FACTORS AFFECTING THE TRANSIENT FLOW OF FLUID THROUGH AN ORIFICE IN REALISTIC CONDITIONS

During operations, damage can occur with a resulting ingress or egress of fluid. The incoming water affects the reserve buoyancy and it can also change stability and hull girder loading. During a flooding event it is vital that the flow through the damaged orifice and the movement of floodwater around the structure can be predicted quickly to avoid further damage and ensure environmental safety. The empirical measure coefficient of discharge is used as a simplified method to quantify the flooding rate. In many internal flow applications the coefficient of discharge is estimated to be 0.6 but recent research shows that it can vary considerably when applied to transient flooding flows. This paper uses an experimental setup to investigate how changes to the orifice edges and position within the structure affect the flow. It is then used to investigate the coefficient in a more realistic scenario, a static compartment in waves.

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MODELING OF TRANSIENT FLOW THROUGH CAPILLARY TUBE- SUCTION LINE HEAT EXCHANGERS

Equipment ◽

10.1615/ihtc13.p18.280 ◽

2006 ◽

Author(s):

A. L. Seixlack ◽

R. A. Navas

Keyword(s):

Heat Exchangers ◽

Transient Flow ◽

Capillary Tube ◽

Suction Line ◽

Flow Through ◽

Tube Suction

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Numerical Simulation of Transient Flow Inside Nozzle on Gasoline Direct Injection Engine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.466-467.1237 ◽

2012 ◽

Vol 466-467 ◽

pp. 1237-1241

Author(s):

Yan Hua Wang ◽

Shi Chun Yang ◽

Yun Qing Li

Keyword(s):

Kinetic Energy ◽

Transient Flow ◽

Direct Injection ◽

Flow Characteristics ◽

Internal Flow ◽

Turbulence Kinetic Energy ◽

Gasoline Direct Injection ◽

Injection Hole ◽

Gasoline Direct Injection Engine ◽

Nozzle Configuration

To achieve transient flow characteristics at exit of nozzle orifice on gasoline direct injection engine, two phase Euler-Euler schemes was used to simulate the internal flow of the swirl nozzle. Different flow characteristics were calculated in the simulation. Different kinds of nozzle configuration were studied. Cavitaion and swirl flow occured in the nozzles. Injection hole configuration matters more than area variation of swirl tangential slot to discharge coefficient of the studied nozzle. Discharge coefficient changes a little along the injection hole length. The area of the swirl tangrntial slot plays an important throttling action in nozzle internal flow. Smaller area of swirl tangential slot generates larger degree cavitation but smaller mean injection velocity. Turbulence kinetic energy changes with the time of cavitation and swirl field occurring and the nozzle configuration. Before the appearance of cavitation, smaller inclination angle of orifice can generate more turbulence kinetic energy. After that moment, turbulence kinetic energy varies with different configuration. Along injection hole length, turbulence kinetic energy obviously varies. These flow characteristics affect primary atomization and will be as input for next spray simulation. They are also applied to design reference for injection nozzle.

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The temporal evolution of neutral modes in the impulsively started flow through a circular pipe and their connection to the nonlinear stability of Hagen–Poiseuille flow

Journal of Fluid Mechanics ◽

10.1017/s0022112001007674 ◽

2002 ◽

Vol 457 ◽

pp. 339-376 ◽

Cited By ~ 8

Author(s):

ANDREW G. WALTON

Keyword(s):

Poiseuille Flow ◽

Multiple Scales ◽

Stability Boundary ◽

Circular Cross Section ◽

Flow Characteristics ◽

Internal Flow ◽

Bypass Transition ◽

Flow Through ◽

High Reynolds ◽

Wave Limit

The linear stability of the impulsively started flow through a pipe of circular cross-section is studied at high Reynolds number R. A crucial non-dimensional time of O(R7/9) is identified at which the disturbance acquires internal flow characteristics. It is shown that even if the disturbance amplitude at this time is as small as O(R−22/27) the subsequent evolution of the perturbation is nonlinear, although it can still be followed analytically using a multiple-scales approach. The amplitude and wave speed of the nonlinear disturbance are calculated as functions of time and we show that as t → ∞, the disturbance evolves into the long-wave limit of the neutral mode structure found by Smith & Bodonyi in the fully developed Hagen–Poiseuille flow, into which our basic flow ultimately evolves. It is proposed that the critical amplitude found here forms a stability boundary between the decay of linear disturbances and ‘bypass’ transition, in which the fully developed state is never attained.

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Determination of the Near-Wellbore Pressure Drop for Dual Casing in Hydraulic Fracturing and Refracturing Applications

10.2118/205234-ms ◽

2022 ◽

Author(s):

Joern Loehken ◽

Davood Yosefnejad ◽

Liam McNelis ◽

Bernd Fricke

Keyword(s):

Pressure Drop ◽

Hydraulic Fracturing ◽

Complex Flow ◽

Cement Layer ◽

Natural Rock ◽

Wellbore Pressure ◽

Flow Through ◽

The Difference ◽

Coefficient Of Discharge

Abstract Due to the increases in completion costs demand for production improvements, fracturing through double casing in upper reservoirs for mature wells and refracturing early stimulated wells to change the completion design, has become more and more popular. One of the most common technologies used to re-stimulate previously fracked wells, is to run a second, smaller casing or tubular inside of the existing and already perforated pipes of the completed well. The new inner and old outer casing are isolated from each other by a cement layer, which prevents any hydraulic communication between the pre-existing and new perforations, as well as between adjacent new perforations. For these smaller inner casing diameters, specially tailored and designed re-fracturing perforation systems are deployed, which can shoot casing entrance holes of very similar size through both casings, nearly independent of the phasing and still capable of creating tunnels reaching beyond the cement layer into the natural rock formation. Although discussing on the API RP-19B section VII test format has recently been initiated and many companies have started to test multiple casing scenarios and charge performance, not much is known about the complex flow through two radially aligned holes in dual casings. In the paper we will look in detail at the parameters which influence the flow, especially the Coefficient of Discharge of such a dual casing setup. We will evaluate how much the near wellbore pressure drop is affected by the hole's sizes in the first and second casing, respectively the difference between them and investigate how the cement layer is influenced by turbulences, which might build up in the annulus. The results will enhance the design and provide a better understanding of fracturing or refracturing through double casings for hydraulic fracturing specialists and both operation and services companies.

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Design of Pressurized Metered Dose Inhalers Modeling of Internal Flow and Atomization

Journal of Medical Devices ◽

10.1115/1.3443745 ◽

2010 ◽

Vol 4 (2) ◽

Author(s):

Henk Versteeg ◽

Abdul Qaiyum Shaik

Keyword(s):

Experimental Work ◽

Equilibrium Model ◽

Lung Diseases ◽

Internal Flow ◽

Flow Conditions ◽

Metered Dose Inhalers ◽

Numerical Predictions ◽

Metered Dose ◽

Flow Through ◽

Pressurized Metered Dose Inhalers

Pressurized metered-dose inhalers (pMDIs) have been the most effective therapeutic treatment for controlling lung diseases such as asthma and COPD. The flow through a two-orifice system of pMDI is very complex and poorly understood. Previous experimental work has shown that metastability may play a significant role in determining the flow conditions inside pMDIs. In this paper, we present the findings of a homogeneous equilibrium model with those of a delayed equilibrium model (DEM) accounting for propellant metastability. These results are compared with the available experimental and numerical predictions Further, the DEM was applied with HFA propellants R134A and R227, and the results were compared with traditional propellant R12.

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Impact of Print Parameters on Pressure Drop in Turbulent Flow Through 3-D Printed Pipes

Volume 2: Fluid Mechanics; Multiphase Flows ◽

10.1115/fedsm2020-20252 ◽

2020 ◽

Author(s):

Thomas G. Shepard ◽

John Wentz ◽

Tucker Bender ◽

Derek Olmschenk ◽

Alex Gutenberg

Keyword(s):

Surface Roughness ◽

Additive Manufacturing ◽

Flow Characteristics ◽

Internal Flow ◽

Acrylonitrile Butadiene Styrene ◽

Industrial Applications ◽

Relative Pressure ◽

Fused Filament Fabrication ◽

Pressure Drops ◽

Flow Through

Abstract Flow conduits made via additive manufacturing, commonly referred to as 3-D printing, are of increasing interest for a variety of industrial applications due to the ability to create unique and conformal flow paths that would not be possible with other fabrication techniques. Fused filament fabrication (FFF) is an additive manufacturing technique that is seeing new interest in the creation of internal flow channels with its ability to print high-temperature polymers and soluble supports. Printing parameter choices in the FFF printing process result in surfaces that can have significant profile differences that may significantly impact the flow characteristics within the conduits. In this study, two print parameters were experimentally studied for turbulent water flow through circular pipes created by fused filament fabrication out of acrylonitrile butadiene styrene (ABS). The print layer orientation relative to the flow was investigated for printing layers parallel, perpendicular, and at 45 degrees from the flow axis. Layer thickness were varied from 0.254 mm to 0.330 mm and all channels were created using soluble support structures. Pressure drops were measured for fully developed flow through pipes with an inside diameter of 5 mm and Reynolds numbers up to 62,000. Results are presented in terms of relative pressure drops as well as the wall surface roughness that would lead to such impacts. These flow-determined grain surface roughnesses are then compared against measurements of print surface roughness.

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1D-3D coupling investigation of hydraulic transient for power-supply failure of centrifugal pump-pipe system

Journal of Hydroinformatics ◽

10.2166/hydro.2019.122 ◽

2019 ◽

Vol 21 (5) ◽

pp. 708-726 ◽

Cited By ~ 1

Author(s):

Xiaoqin Li ◽

Xuelin Tang ◽

Min Zhu ◽

Xiaoyan Shi

Keyword(s):

Turbulent Flows ◽

Flow Rate ◽

Power Supply ◽

Nuclear Power ◽

Transient Flow ◽

Internal Flow ◽

Transition Process ◽

Pipeline System ◽

Pipe System ◽

Rotating Speed

Abstract In the pumping station, the main feedwater system and the reactor system of nuclear power plant, power-supply failure causes strong hydraulic transients. One-dimensional method of characteristics (1D-MOC) is used to calculate the transient process in the pipeline system while three-dimensional (3D) computational fluid dynamics is employed to analyze the turbulent flows inside the pump and to obtain the performance parameters of the pump, and the data exchanges on the boundary conditions of the shared interface between 1D and 3D domains are updated based on the MpCCI platform. Based on the equation of motion of the pump motion parts, the relationship between the external characteristics and the internal flow field in the pump is further investigated because the dynamic behavior of the pump and the detailed fluid field evolutions inside the pump are captured during the transition process, and the transient flow rate, rotating speed, and pressure inside the impeller are comprehensively investigated. Meanwhile, compared with the data gained by experiment and traditional 1D-MOC, the relative errors of rotating speed and the flow rate obtained by 1D-3D coupling method are smaller than those by 1D-MOC. Furthermore, the influences of the main coupling parameters and coupling modes on the calculation results are analyzed, and the cause of the deviation is further explained.

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Numerical simulation and experiment for study on internal flow pattern of vortex pump

Engineering Computations ◽

10.1108/ec-09-2018-0420 ◽

2019 ◽

Vol 36 (5) ◽

pp. 1579-1596

Author(s):

Hui Quan ◽

Yi Chai ◽

Rennian Li ◽

Jianhui Guo

Keyword(s):

Flow Pattern ◽

Theoretical Foundation ◽

Internal Flow ◽

Content Type ◽

Vortex Pump ◽

Hydraulic Design ◽

Through Flow ◽

Simulation And Experiment ◽

Flow Through ◽

Working Out

Purpose The special structure of the vortex pump contributes to its complex internal flow pattern. A type of horizontal 150WX-200-20 vortex pump is taken as a research subject to deeply study the progression and distribution of flow pattern in its channel. To explain the mechanism of flow in this pump, numerical analysis of the whole flow and experiment have been conducted. Design/methodology/approach The authors studied and analyzed the distribution and evolution of flow pattern under different flow, such as circulating-flow, through-flow and other forms. Finally, a model of flow pattern in the vortex pump has been built, which has more perfectly fit the reality. Findings They are through-flow affected by circulating-flow, main and subsidiary circulating-flow, vortices between vanes and other vortices (or liquid impingement) in volute. Entering the pump, part of the flow stays in vanes and turn into vortices while the other goes into the front chamber. The flow that runs into the front chamber will be divided into two parts. One part will be collected by viscosity into a vortex rope when it passing through the interface between the impeller and the vaneless chamber, which closely relates to the circulating-flow, and the rest directly goes out of the field through the diffuser. Besides, a fraction of circulating-flow joins the through-flow when it goes through the section V and leaves the pump. Originality/value The research results build a theoretical foundation for working out the flow mechanism of the vortex pump, improving its efficiency and optimizing its hydraulic design.

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