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Two phase mixing comparison, oil contamination comparison and manufacturing accuracy effect on calibration of slotted orifice meterSparks, Sara A. 15 November 2004 (has links)
In previous studies the slotted orifice plate has demonstrated superior performance characteristics to those of the standard orifice plate. In this study, these comparisons are investigated further. The response characteristics of the slotted orifice plate to the standard orifice plate and V-Cone for two-phase flows of water and air at various qualities, flow rates, and pressures are shown visually. The effect of oil as it flows through a slotted orifice plate and standard orifice plate are visually documented. The effect of manufacturing accuracy on the slotted orifice plates is investigated as to the effect on the coefficient of discharge, percent change in pressure, and Reynolds number. The slotted orifice plate mixes two-phase flow better than the standard orifice plate and V-Cone. There is a manufacturing effect on the slotted orifice plates; the larger the area of the slots, the larger the discharge coefficient.
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Two phase mixing comparison, oil contamination comparison and manufacturing accuracy effect on calibration of slotted orifice metersSparks, Sara A. 15 November 2004 (has links)
In previous studies the slotted orifice plate has demonstrated superior performance characteristics to those of the standard orifice plate. In this study, these comparisons are investigated further. The response characteristics of the slotted orifice plate to the standard orifice plate and V-Cone for two-phase flows of water and air at various qualities, flow rates, and pressures are shown visually. The effect of oil as it flows through a slotted orifice plate and standard orifice plate are visually documented. The effect of manufacturing accuracy on the slotted orifice plates is investigated as to the effect on the coefficient of discharge, percent change in pressure, and Reynolds number. The slotted orifice plate mixes two-phase flow better than the standard orifice plate and V-Cone. There is a manufacturing effect on the slotted orifice plates; the larger the area of the slots, the larger the discharge coefficient.
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Study of a naturally oscillating triangular-jet flow.Lee, Soon-Kong January 2009 (has links)
This thesis reports on the structure of the flow inside a nozzle which produces a naturally oscillating jet flow. The nozzle consists of a short cylindrical chamber with a concentric triangular-inlet orifice at one end and a circular exit lip at the other end. This triangular-jet nozzle was developed from the “fluidic-precessing-jet” (FPJ) nozzle, which has a similar arrangement of components, but has a circular rather than a triangular inlet. For reliably oscillating flow, the FPJ nozzle should have an inlet-to-chamber expansion ratio of at least 5.0, a chamber lengthto- diameter ratio between 2.6 and 2.8, and an exit-lip height of about 0.1 chamber diameters. The triangular-jet nozzle produces a continuously and aperiodically oscillating jet flow which is different from the FPJ flow. The oscillation occurs at smaller inlet-to-chamber expansion ratios (2.1 ≲ D /de₁ ≲ 3.5) and over a wider range of chamber lengths (2.0 ≲ L /D ≲ 2.5). The initial spreading angle of the jet flow is smaller, but is still much larger than that of non-oscillating, axisymmetric turbulent-jet flows. In addition, the external “oscillating-triangular-jet” (OTJ) flow has preferred azimuthal directions which are aligned with the three corners of the orifice. The kinetic-energy-loss coefficient of the OTJ nozzle is much smaller than that of the FPJ nozzle because oscillation occurs at much smaller inlet-to-chamber expansion ratios. For a narrow range of length-to-diameter ratios (1.00 ≲ L/D ≲ 1.25), the triangular-inlet nozzle can also produce a non-oscillating or “stationary deflected triangular jet” (SDTJ) which reattaches asymmetrically to the inside surface of the cylindrical chamber. The SDTJ has a weak tendency to oscillate, which suggests that flow patterns required for self-excited oscillation are already present in the SDTJ flow. Surface-flow visualisation and surface-pressure measurements in the SDTJ nozzle have provided the location of critical points and bifurcation lines on the chamber wall, and from this the topology of the SDTJ flow is deduced. Some details of the flow such as a jet-reattachment node near the chamber exit and a strong swirl adjacent to the inlet orifice are known from previous studies of the FPJ flow, but there are many newly observed features. The most easily identified of these are two sink-focus separation points, one on each side of the reattachment node but closer to the inlet plane. The foci counter rotate and are of unequal size. Reverse flow through the exit plane of the chamber is attracted to the larger focus. The vortex core rising from each focus is entrained by the reattaching-jet (SDTJ) flow and is drawn out of the chamber. A backward-facing pressure probe placed in the OTJ “reattaching-flow” region of chamber wall can be used as a reliable detector of jet-flow oscillation. Cross-correlating the signal from this detector probe with simultaneous static-pressure measurements elsewhere on the chamber wall gives a conditionally-averaged pressure on the wall of the OTJ chamber. The OTJ wall-pressure distribution has the same features as the SDTJ surface-pressure distribution, but it has greater asymmetry about a mirror plane drawn through the chamber axis and the detector probe. An array of three backward-facing pressure probes has been used as an “event detector” for conditionally-sampled (PIV) measurements of non-axial velocity components in cross-sections of the OTJ nozzle. The event-detection scheme responds only to a preselected (counter-clockwise) direction of motion of the oscillating-jet flow. The streamline patterns constructed from the conditionally-sampled measurements confirm the presence of the jet-reattachment node, the swirl and the sink foci identified from the SDTJ surface-flow visualisation. The shear-layer interaction between the jet from the triangular orifice and the swirl (adjacent to the inlet plane) produces strong longitudinal vortices in the ensemble-averaged flow. The jet flow distributes these vortices through the length of the chamber. Vortex cores representing the vortices are reconstructed by tracking streamline foci from one PIV cross-section plane to another. The tracking process includes the connection and termination of vortex cores in a manner which is consistent with the Helmholtz vortex law. In this flow field, the vortex core produced by the swirl and the vortex core rising from the larger sink-focus vortex on the chamber wall are connected to form a loop. The extent to which this vortex loop is contained within the chamber determines whether or not the flow is oscillating. If only a small fraction (e.g. 8%) of the vortex circulation passes through the exit plane of the nozzle, the loop is trapped inside the chamber and the deflected jet oscillates. If the length of the chamber is halved, about 35% of vortex circulation escapes from the nozzle and the oscillation stops. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1353005 / Thesis (Ph.D.) - University of Adelaide, School of Mechanical Engineering, 2009
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Study of a naturally oscillating triangular-jet flow.Lee, Soon-Kong January 2009 (has links)
This thesis reports on the structure of the flow inside a nozzle which produces a naturally oscillating jet flow. The nozzle consists of a short cylindrical chamber with a concentric triangular-inlet orifice at one end and a circular exit lip at the other end. This triangular-jet nozzle was developed from the “fluidic-precessing-jet” (FPJ) nozzle, which has a similar arrangement of components, but has a circular rather than a triangular inlet. For reliably oscillating flow, the FPJ nozzle should have an inlet-to-chamber expansion ratio of at least 5.0, a chamber lengthto- diameter ratio between 2.6 and 2.8, and an exit-lip height of about 0.1 chamber diameters. The triangular-jet nozzle produces a continuously and aperiodically oscillating jet flow which is different from the FPJ flow. The oscillation occurs at smaller inlet-to-chamber expansion ratios (2.1 ≲ D /de₁ ≲ 3.5) and over a wider range of chamber lengths (2.0 ≲ L /D ≲ 2.5). The initial spreading angle of the jet flow is smaller, but is still much larger than that of non-oscillating, axisymmetric turbulent-jet flows. In addition, the external “oscillating-triangular-jet” (OTJ) flow has preferred azimuthal directions which are aligned with the three corners of the orifice. The kinetic-energy-loss coefficient of the OTJ nozzle is much smaller than that of the FPJ nozzle because oscillation occurs at much smaller inlet-to-chamber expansion ratios. For a narrow range of length-to-diameter ratios (1.00 ≲ L/D ≲ 1.25), the triangular-inlet nozzle can also produce a non-oscillating or “stationary deflected triangular jet” (SDTJ) which reattaches asymmetrically to the inside surface of the cylindrical chamber. The SDTJ has a weak tendency to oscillate, which suggests that flow patterns required for self-excited oscillation are already present in the SDTJ flow. Surface-flow visualisation and surface-pressure measurements in the SDTJ nozzle have provided the location of critical points and bifurcation lines on the chamber wall, and from this the topology of the SDTJ flow is deduced. Some details of the flow such as a jet-reattachment node near the chamber exit and a strong swirl adjacent to the inlet orifice are known from previous studies of the FPJ flow, but there are many newly observed features. The most easily identified of these are two sink-focus separation points, one on each side of the reattachment node but closer to the inlet plane. The foci counter rotate and are of unequal size. Reverse flow through the exit plane of the chamber is attracted to the larger focus. The vortex core rising from each focus is entrained by the reattaching-jet (SDTJ) flow and is drawn out of the chamber. A backward-facing pressure probe placed in the OTJ “reattaching-flow” region of chamber wall can be used as a reliable detector of jet-flow oscillation. Cross-correlating the signal from this detector probe with simultaneous static-pressure measurements elsewhere on the chamber wall gives a conditionally-averaged pressure on the wall of the OTJ chamber. The OTJ wall-pressure distribution has the same features as the SDTJ surface-pressure distribution, but it has greater asymmetry about a mirror plane drawn through the chamber axis and the detector probe. An array of three backward-facing pressure probes has been used as an “event detector” for conditionally-sampled (PIV) measurements of non-axial velocity components in cross-sections of the OTJ nozzle. The event-detection scheme responds only to a preselected (counter-clockwise) direction of motion of the oscillating-jet flow. The streamline patterns constructed from the conditionally-sampled measurements confirm the presence of the jet-reattachment node, the swirl and the sink foci identified from the SDTJ surface-flow visualisation. The shear-layer interaction between the jet from the triangular orifice and the swirl (adjacent to the inlet plane) produces strong longitudinal vortices in the ensemble-averaged flow. The jet flow distributes these vortices through the length of the chamber. Vortex cores representing the vortices are reconstructed by tracking streamline foci from one PIV cross-section plane to another. The tracking process includes the connection and termination of vortex cores in a manner which is consistent with the Helmholtz vortex law. In this flow field, the vortex core produced by the swirl and the vortex core rising from the larger sink-focus vortex on the chamber wall are connected to form a loop. The extent to which this vortex loop is contained within the chamber determines whether or not the flow is oscillating. If only a small fraction (e.g. 8%) of the vortex circulation passes through the exit plane of the nozzle, the loop is trapped inside the chamber and the deflected jet oscillates. If the length of the chamber is halved, about 35% of vortex circulation escapes from the nozzle and the oscillation stops. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1353005 / Thesis (Ph.D.) - University of Adelaide, School of Mechanical Engineering, 2009
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The effects of viscosity on vortex-orifice flowZielinski, Paul B. January 1965 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. Includes bibliographical references.
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Micropores Fabricated Using Undercut Etching Techniques for Ultra Small Droplets Formation and Its Pharmaceutical ApplicationsLan, Chun-Hung 09 September 2010 (has links)
This research successfully created an ultra-small orifice utilizing undercut fabrication process in a droplet-based microfluidics chip. The proposed novel T-junction structure with ultra-small orifice has a lot of advantages, including long-term stability for uniform droplets formation, reproducible ultra-small size droplet and tunable droplet size. The hydraulic diameter of the orifice is under 2 £gm, and the size of micro droplet produced from the orifice can be tuned to less than 10 £gm in diameter. Chitosan droplet can be produced by the proposed chip, which is usually adopted for medical applications. Surface modification technique was applied to modify the surface of microchannel to be hydrophobic for eaily producing hydro-droplets. Experimental results show that the ultra-small orifice microfluidics chip can steadily produce water-in-oil droplets only by controlling the flow ratio between dispersed phase and continuous phase flow rates. The size of the water-in-oil droplets can be tunable from 22 £gm to 6.5 £gm in diameter by adjusting the flow rate ratio of the continuous and disperse phase flows from 1 to 3.5 and the hydraulic diameter of the orifice is 1.1 £gm. And the size of the chitosan-in-oil droplets also can be tunable from 59 £gm to 27 £gm by adjusting the flow rate ratio of the continuous and disperse phase flows from 4 to 8. The proposed microchip has advantages including ease of control, low cost, and high throughput. The proposed technique can be widely applied on emulsion and micro droplet generation.
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Measurements versus Predictions for a Hybrid (Hydrostatic plus Hydrodynamic Thrust Bearing for a Range of Orifice DiametersEsser, Paul R. 2010 May 1900 (has links)
A fixed geometry hybrid thrust bearing is investigated with three different supply
orifice diameters. The test rig uses a face-to-face thrust bearing design, with the test
bearing acting as the rotor loading mechanism. A hydraulic shaker applies the static
axial load, which is reacted by a second thrust bearing. The rotor is supported radially
by two water-lubricated fluid film journal bearings and is attached to a 30,600 rpm
motor via a high speed coupling with very low axial stiffness. Thrust bearings with
three different orifice diameters (1.63, 1.80, and 1.93 mm) are tested for a range of
supply pressures, fluid film thicknesses, and rotational speeds. The water-lubricated test
bearings have eight pockets, with feed orifices located centrally in each pocket.
Experimental results are comparted to predictions found using bulk flow model
HYDROTHRUST.
Analysis of the data reveals generally good agreements between predictions and
measurements. Thrust-bearing inlet supply and inner radius flow rates all decreased
with decreasing orifice diameters and bearing axial clearances. In most cases, the
bearings with larger orifice diameters exhibit higher recess pressure ratios, operating clearances, and flow rates. The largest orifice diameter configuration does not display
higher recess pressure ratios or operating clearances at high speeds for some supply
pressures, but it does continue to require additional lubricant flow rate compared to the
smaller orifice bearings. In these cases, the results are not reflected in predictions, which
otherwise correlate very well with experimental measurements. Estimations of static
loading axial stiffness are obtained using experimental results.
An optimum hybrid thrust bearing orifice diameter will depend on the conditions
of individual applications. Larger orifices generally provide larger operating clearances
and higher stiffnesses, but also require higher flow rates. For most applications, a
compromise of bearing performance parameters will be desired. The test results and
comparisons presented will aid in sizing orifice diameters for future hybrid thrust
bearing designs.
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Mathematical modelling of flow downstream of an orifice under flow-accelerated corrosionSanama Goufan, Conrad Constant January 2017 (has links)
The main objective of this work is to establish an analytical model to evaluate the rate of corrosion in a horizontal pipe downstream of an orifice under flow-accelerated corrosion (FAC). FAC is a serious issue in nuclear and fossil power plants. In this work, an experimental setup was built to observe the effect of the flow on corrosion inside a tube. The experiments confirmed that the flow inside the tube caused more corrosion. However, accurate experimental data from literature has been selected and correlated by dimensional analysis, the modelling method of repeating variables and the Buckingham Pi theorem. It was found that the Sh number and the relative distance from the orifice are the main dimensionless parameters influencing FAC downstream of an orifice. The maximum value of the FAC rate could be well-predicted for the OR of 0.25, while the location of the maximum FAC rate could be well predicted for the OR of 0.5. The maximum FAC rate occurs between 2D to 4D downstream of the orifice and increases with a decreasing OR. This work could be useful for professionals in industry and researchers in the field and could be the starting point for a new way of evaluating the FAC rate downstream of a flow’s singularity. / Dissertation (MSc)--University of Pretoria, 2017. / Mechanical and Aeronautical Engineering / MSc / Unrestricted
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Overcoming Barriers to Natural Orifice Translumenal Endoscopic Surgery (NOTES)Schomisch, Steve J. 28 September 2009 (has links)
No description available.
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AN ASSESSMENT OF THE ACCURACY OF MAGENTIC RESONANCE PHASE VELOCITY MAPPING IN TURBULENT FLOW THROUGH ORIFICESPidaparthi, Sahitya 17 February 2011 (has links)
No description available.
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