Effect of rotor–stator axial spacing on the pressure-rise performance and flow field in an axial pump

2018 ◽  
Vol 233 (6) ◽  
pp. 727-737
Author(s):  
Han Xu ◽  
Donghai Jin ◽  
Dakun Sun ◽  
Lin Du ◽  
Xingmin Gui ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Rate ◽  
Particle Image ◽  
Incidence Angle ◽  
Pressure Rise ◽  
Low Flow ◽  
Working Fluid ◽  
Rate Condition ◽  
Axial Pump ◽  
Image Velocimetry

In this paper, the effect of the rotor–stator axial spacing is investigated in an axial pump with the working fluid of water. The pressure-rise performance was tested at a range of flow rates. Results indicate that decreased axial spacing generates improved hydraulic head, especially when the flow rate is low. Particle image velocimetry measurement was performed and flow fields for five rotor phases were obtained in a low flow rate condition. Particle image velocimetry results demonstrate that the stator inlet flow is both affected by the wake of the rotor and the existence of the stator. As the axial spacing gets close, the incidence angle of the stator decreases and the flow separation on the suction side is restrained, and therefore the pressure rise ability is improved.

A particle image velocimetry study on the pulsatile flow characteristics in straight tubes with an asymmetric bulge

2000 ◽  
Vol 214 (5) ◽  
pp. 655-671 ◽  
Author(s):  
S C M Yu ◽  
J B Zhao
Keyword(s):  
Particle Image Velocimetry ◽  
Steady Flow ◽  
Pulsatile Flow ◽  
Flow Condition ◽  
Particle Image ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Working Fluid ◽  
Flow Conditions ◽  
Image Velocimetry

Flow characteristics in straight tubes with an asymmetric bulge have been investigated using particle image velocimetry (PIV) over a range of Reynolds numbers from 600 to 1200 and at a Womersley number of 22. A mixture of glycerine and water (approximately 40:60 by volume) was used as the working fluid. The study was carried out because of their relevance in some aspects of physiological flows, such as arterial flow through a sidewall aneurysm. Results for both steady and pulsatile flow conditions were obtained. It was found that at a steady flow condition, a weak recirculating vortex formed inside the bulge. The recirculation became stronger at higher Reynolds numbers but weaker at larger bulge sizes. The centre of the vortex was located close to the distal neck. At pulsatile flow conditions, the vortex appeared and disappeared at different phases of the cycle, and the sequence was only punctuated by strong forward flow behaviour (near the peak flow condition). In particular, strong flow interactions between the parent tube and the bulge were observed during the deceleration phase. Stents and springs were used to dampen the flow movement inside the bulge. It was found that the recirculation vortex could be eliminated completely in steady flow conditions using both devices. However, under pulsatile flow conditions, flow velocities inside the bulge could not be suppressed completely by both devices, but could be reduced by more than 80 per cent.

Experimental Investigation of Flow Blurring Atomizer at Near Field Using Particle Image Velocimetry

2019 ◽  
Author(s):  
Raju Murugan ◽  
Dhanalakshmi Sellan ◽  
Pankaj S. Kolhe
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Rate ◽  
Liquid Flow ◽  
Particle Image ◽  
Liquid Flow Rate ◽  
Diagnostic Technique ◽  
Reynolds Stresses ◽  
Full Field ◽  
Image Velocimetry ◽  
Spray Droplets

Abstract Two-fluid flow blurring atomization is characterized by the backflow recirculation of the air phase in the liquid pipe by bifurcation of the liquid and airflow. Most of the primary spray process is completed in the injector due to the penetration of air into the liquid tube. Thus, the majority of the liquid ligaments are converted into a fine spray at the outlet of the nozzle. Experiments were performed with two different air to liquid ratios (0.6 and 1) by mass, where water is considered as the liquid and airflow was kept constant (0.2 g/s). To change the ALR, the liquid flow rate was changed. Particle image velocimetry (PIV) diagnostic technique provides the full-field velocity of the spray droplets (discrete phase). It may be noted that sprays are self-seeded and PIV measurements reflect the droplet velocities instead of air velocity. To understand the effect of the spatial resolution of PIV on spray droplet velocity; experiments were conducted at three different spatial resolutions (11.8, 16.4 and 23.22 μm/pixel) for each ALR. As the ALR is increased, the mass of the liquid in the spray decreases, resulting in finer atomization and velocity of the spray droplets. This means that finer droplets are generated for the same mass of air at a lower liquid flow rate as compared to higher liquid flow rate. Note that Reynolds stresses provide an indication of the turbulent breakup of the droplet and larger magnitudes observed for higher ALR indicate finer atomization.

Investigation of Flow Field at the Inlet of a Turbocharger Compressor Using Digital Particle Image Velocimetry

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Deb Banerjee ◽  
Rick Dehner ◽  
Ahmet Selamet ◽  
Kevin Tallio ◽  
Keith Miazgowicz ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Particle Image ◽  
Flow Reversal ◽  
High Mass ◽  
Reversed Flow ◽  
Image Velocimetry

Abstract The flow field at the inlet of a turbocharger compressor has been studied through stereoscopic particle image velocimetry (SPIV) experiments under different operating conditions. It is found that the flow field is quite uniform at high mass flow rates; but as the mass flow rate is reduced, flow reversal from the impeller is observed as an annular ring at the periphery of the inlet duct. The inception of flow reversal is observed to occur in the mid-flow operating region, near peak efficiency, and corresponds to an incidence angle of about 15.5 deg at the inducer blade tips at all tested speeds. This reversed flow region is marked with high tangential velocity and rapid fluctuations. It grows in strength with reducing mass flow rate and imparts some of its angular momentum to the forward flow due to mixing. The penetration depth of the reversed flow upstream from the inducer plane is found to increase quadratically with decreasing flow rate.

Development of 3-D Printed Optically Clear Rigid Anatomical Vessels for Particle Image Velocimetry Analysis in Cardiovascular Flow

2019 ◽  
Author(s):  
Nicholas Stanley ◽  
Ashley Ciero ◽  
William Timms ◽  
Rodward L. Hewlin
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Flow Analysis ◽  
Index Of Refraction ◽  
Working Fluid ◽  
Post Processing ◽  
Anatomical Models ◽  
Tracer Particles ◽  
Image Velocimetry ◽  
Flow Tracer

Abstract In recent years, blood flow analysis of diseased arterial mock vessels using particle image velocimetry (PIV) has been hampered by the inability to fabricate optically clear anatomical vessel models that realistically replicate the complex morphology of arterial vessels and provide highly resolved flow images of flow tracer particles. The aim of the present work is to introduce an approach for producing optically clear rigid anatomical models that are suitable for PIV analysis using a common 3-D SLA inkjet printing process (using a Formlabs Form 2 3-D printer) and stock clear resin (RS-F2-GPCL-04). By matching the index of refraction (IOR) of the working fluid to the stock clear resin material, and by printing the part in a 45-degree print orientation, a clear anatomical model that allows clear visualization of flow tracer particles can be produced which yields highly resolved flow images for PIV analyses. However, a 45-degree print orientation increases the need for post processing due to an increased amount of printed support material. During post processing, the part must be wet sanded in several steps and surface finished with Novus Plastic Polish 3 Step System to achieve the final surface finish needed to yield high quality flow images. The fabrication methodology of the clear anatomical models is described in detail.

In-Cylinder Fuel-Air Mixture Investigation by Particle Image Velocimetry in a GDI Engine

2004 ◽  
Author(s):  
G. Valentino ◽  
M. Auriemma ◽  
G. Caputo ◽  
F. E. Corcione
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Rate ◽  
Particle Image ◽  
Direct Injection ◽  
Air Flow ◽  
Piv Technique ◽  
Fuel Jet ◽  
Image Velocimetry ◽  
Gdi Engine ◽  
Intake Flow

The present paper aims at providing experimental results on the spray structure and its interaction with the air flow generated by the intake ducts of a commercial light duty gasoline direct injection (GDI) engine head. The investigation was carried out by the Particle Image Velocimetry (PIV) technique to investigate the air flow and fuel droplets velocity evolution within a prototype cylinder with optical accesses. Experiments were carried out at various operating conditions reproducing the mixture preparation for an early injection strategy. The PIV technique was applied in a flow test rig assembled with a blower, which supplied the intake flow rate, connected to the intake manifold of a commercial 4-valve direct injection gasoline engine head modified to lay down an external driving control system for the valves motion. Experiments were taken equipping the engine head with a common rail injection system able to work up to 10 MPa, and a swirled type injector having a nozzle diameter of 0.50 mm and a nominal cone angle of 60°. Tests were taken, on a plane crossing the cylinder and the injector axes, supplying to the prototype cylinder an intake flow rate of 29 m3/h and spraying the gasoline at two injection timings in a range of injection pressure of 6, 8, and 10 MPa. The results provided detailed information on the intake flow field behavior and the evolution of fuel jet within the air flow. The intake flow velocity distribution, acquired at different cam angle during the induction, showed the development of an initial clockwise tumble flow with a tendency to produce two large flow structures: a main counter clockwise vortex and a clockwise ones located at the opposite side of the field of view. Images of the interaction of the fuel with the tumble motion displayed, firstly, a fuel jet shape that traveled not affected by the tumble motion because of its high momentum. Later during the intake, the fuel was strongly distorted by the air motion with the formation of clusters detached from the main jet and spread within the cylinder so allowing to hypothesize that the intake bulk flow may be a crucial parameter to control the fuel penetration and the droplets distribution within the cylinder.

Visualization of Macro- and Micromixing Using Two-Color Laser Induced Fluorescence and Particle Image Velocimetry

2006 ◽  
Author(s):  
M. Faes ◽  
D. Mewes
Keyword(s):  
Particle Image Velocimetry ◽  
Source Term ◽  
Particle Image ◽  
Optical Measurement ◽  
Laser Induced Fluorescence ◽  
Working Fluid ◽  
Simultaneous Application ◽  
Measurement Systems ◽  
Local Degree ◽  
Image Velocimetry

The progress in mixing on macro- and microscale is visualized by means of optical measurement systems. The Particle Image Velocimetry (PIV) is used to measure the velocity field inside the mixing system. The source term of the local energy dissipation is calculated by the information of the gradients of velocity. The Laser Induced Fluorescence (LIF) Technique is further developed for the simultaneous application of two different colors. A mixture of an inert and a reacting fluorescent dye is injected into a vessel. The macromixing is reflected by the inert dye serving as a tracer. Mixing on molecular scale is required for the progress of chemical reactions. Therefore the reacting dye indirectly visualizes the micromixing by changing its fluorescent characteristics during the reaction. The concentration fields of the two dyes are determined from measured fluorescence intensities. Based on these the local degree of deviation is calculated for detecting the areas of micromixing. Measurements are performed in a mixing system equipped with two glass cylinders. The working fluid is a mixture of glycerol and some adittional chemicals. The experiments are conducted in the laminar region. The injected dyes are stretched and folded in the flow field of the mixing system creating lamellar structures. The two optical measurement systems are prepared for the analysis of interrelation of macro- and micromixing subject to the local dissipation of energy.

scholarly journals Experimental study on fiber suspensions in a curved expansion duct with particle image velocimetry

2012 ◽  
Vol 16 (5) ◽  
pp. 1414-1418 ◽  
Author(s):  
Xiao-Yu Liang ◽  
Huan-Huan Wu ◽  
Cheng-Xu Tu ◽  
Kai Zhang
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Flow Rate ◽  
Particle Image ◽  
Flow Direction ◽  
Internal Flow ◽  
Concave Wall ◽  
Image Velocimetry ◽  
Inlet Flow Rate ◽  
Convex Wall

The visualization measurement of internal flow field in a curved expansion duct is experimentally studied using particle image velocimetry technology and the influence of flow rate on flow field is analyzed. The streamline distribution and related performance curve in the internal flow field can be figured out through further analysis of experiment data. The results show that fiber orientation is mainly affected by velocity gradient, the fibers near the wall are aligned with the flow direction more quickly than the fibers in intermediate region, and the fibers near the concave wall are more quickly aligned with the flow direction than the convex wall. The larger inlet flow rate which will accordingly lead to increase inlet velocity enables the more quick adaptation and steady of fibers in flow direction.

Single- and Two-Phase Particle Image Velocimetry Characterization of Fluid Flow Within a Liquid Immersion Cooled Electronics Module

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Joshua Gess ◽  
Sushil Bhavnani ◽  
R. Wayne Johnson
Keyword(s):  
Particle Image Velocimetry ◽  
Surface Analysis ◽  
Particle Image ◽  
Control Surface ◽  
Working Fluid ◽  
Management Technique ◽  
Two Phase ◽  
Image Velocimetry ◽  
Liquid Immersion ◽  
Critical Components

With the growth and acceptance of liquid immersion cooling as a viable thermal management technique for high performance microelectronics, fundamental questions regarding the nature of the flow within the system will need to be addressed. Among these are how the coolant is directed toward components of primary interest as well as how other elements within the electronics package may affect the delivery of fluid to these more critical locations. The proposed study seeks to experimentally address these issues with particle image velocimetry (PIV) measurements of unheated and heated flow within an electronics enclosure. The effectiveness of three flow distribution designs at delivering coolant to elements of importance, in this case 6.45 cm2 (1 in.2) components meant to simulate processor chips, has been examined using the vectors yielded by the PIV experimentation in a control surface analysis around these critical components. While these previous scenarios are unheated, two-phase PIV has also been conducted with FC-72 as the working fluid while boiling is taking place. A control surface analysis around all four heated elements within the enclosure shows an expected roughly monotonic increase in the net liquid flow rate to the boiling elements as the power applied to them is increased. Additionally, discretized mapping of how the fluid is entering the area surrounding these boiling elements has been constructed to offer insight into how passive elements should be placed within an electronics enclosure so as to not obstruct or hinder the vital flow of coolant to the most critical components.

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