Numerical and Experimental Analysis of Single Phase Jet Interactions

2016 ◽  
Author(s):  
Freddy Hernandez-Alvarado ◽  
Randy Samaroo ◽  
Dinesh V. Kalaga ◽  
Taehun Lee ◽  
Sanjoy Banerjee ◽  
...  
Keyword(s):  
Single Phase ◽  
Tap Water ◽  
Liquid Jets ◽  
Reynolds Stresses ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Mass Transfer Processes ◽  
Image Velocimetry ◽  
Wide Range ◽  
Jet Interactions

Impinging liquid jets have many applications ranging from manufacturing processes to jet propulsion systems. In thermal applications, they are often used in atomization processes to cool the surfaces in extreme heat and mass transfer processes. In the present work, 2-D Particle Image Velocimetry (PIV) measurements have been performed to study the interaction of multiple vertical liquid jets in single-phase flow. A perforated Perspex plate with seven symmetrically placed holes was used to make the liquid jets of degassed tap water. From the PIV measurements, a wide range of liquid jet velocities were investigated, and hydrodynamic parameters such as the instantaneous velocity fields, axial (z) and radial (r) mean and RMS liquid velocities, vorticity, and in-plane Reynolds stresses have been derived. Transient 3-D CFD simulations have also been performed and compared with the experimental data. Good agreement has been found between the experimental and CFD simulations. Further, Reichardt’s hypothesis (1943) has also been examined to better understand the onset of instability for the single-phase multi jet flow.

Experimental and Numerical Flow Visualization in Patient Specific Pre Operative Human Airway Geometry

2011 ◽  
Author(s):  
Mathias Vermeulen ◽  
Cedric Van Holsbeke ◽  
Tom Claessens ◽  
Jan De Backer ◽  
Peter Van Ransbeeck ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Particle Image ◽  
Patient Specific ◽  
Lung Volume Reduction ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Specific Geometry ◽  
Computational Fluid Dynamics Cfd ◽  
Human Airways

An experimental and numerical platform was developed to investigate the fluidodynamics in human airways. A pre operative patient specific geometry was used to create an identical experimental and numerical model. The experimental results obtained from Particle Image Velocimetry (PIV) measurements were compared to Computational Fluid Dynamics (CFD) simulations under stationary and pulsatile flow regimes. Together these results constitute the first step in predicting the clinical outcome of patients after lung surgeries such as Lung Volume Reduction.

CFD Simulations and PIV Measurements for Optimization of Flow Pattern in a Sieve Plate Extraction Column

2011 ◽  
Vol 391-392 ◽  
pp. 1464-1468
Author(s):  
Chang Chun Duan ◽  
Chun Jiang Liu ◽  
Xi Gang Yuan
Keyword(s):  
Flow Pattern ◽  
Reverse Flow ◽  
Continuous Phase ◽  
Extraction Column ◽  
Sieve Plate ◽  
Cfd Simulations ◽  
Flow Area ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Present work deals with the optimization for flow pattern of continuous phase in a sieve plate extraction column using both computational fluid dynamics (CFD) simulations and particle image velocimetry (PIV) measurements. Firstly single-phase simulation was conducted for the traditional column and it was found that there was a very large reverse flow area between every two plates. Then step by step, by changing the downcomer structure, consisting of inclining downcomers, adding baffles, slotting downcomers and baffles and adjusting the number and size of slots, the reverse flow area was decreased and thereby the flow pattern of continuous phase was optimized. Finally, an optimal flow pattern was obtained with reverse flow area greatly reduced. In order to prove the validity of the simulation results, PIV experiments of two columns were carried out and it was found that the results of simulations and experiments are in good agreement.

scholarly journals Tomographic particle image velocimetry of a water-jet for low volume harvesting of fat tissue for regenerative medicine

2015 ◽  
Vol 1 (1) ◽  
pp. 345-348 ◽  
Author(s):  
Christoph Drobek ◽  
Robert Mau ◽  
Hermann Seitz
Keyword(s):  
Particle Image Velocimetry ◽  
Regenerative Medicine ◽  
Particle Image ◽  
Force Sensor ◽  
Water Jet ◽  
Fat Tissue ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Acting Force

AbstractParticle Image Velocimetry (PIV) measurements of a water-jet for water-assisted liposuction (WAL) are carried out to investigate the distribution of velocity and therefore momentum and acting force on the human sub-cutaneous fat tissue. These results shall validate CFD simulations and force sensor measurements of the water-jet and support the development of a new WAL device that is able to harvest low volumes of fat tissue for regenerative medicine even gentler than regular WAL devices.

PIV Measurements of the Turbulent Secondary Flow in a Three-Dimensional Wall Jet

2010 ◽  
Author(s):  
Lhendup Namgyal ◽  
Joseph W. Hall
Keyword(s):  
Secondary Flow ◽  
Reynolds Shear Stress ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Half Width ◽  
Wall Jet ◽  
Normal Stresses ◽  
Reynolds Stresses ◽  
Piv Measurements ◽  
Image Velocimetry

The lateral half width of the turbulent three-dimensional wall jet is typically five to eight times larger than the vertical half width normal to the wall. Although, the reason for this behavior is not fully understood, it is known to be caused by strong secondary flows that develop in the jet due to presence of the wall. The source of the secondary flow in the jet has been attributed previously with both mean vorticity reorientation and to anisotropy in the Reynolds normal stresses, but until now there have been no measurements of these quantities in this flow. Particle Image Velocimetry (PIV) measurements are used herein to measure the Reynolds stresses that contribute to the secondary flow in a turbulent three-dimensional wall jet formed using a circular contoured nozzle with exit Reynolds number of 250,000. In particular, the Reynolds shear stress, vw was found to be significantly smaller throughout the jet than the differences in the Reynolds normal stresses (v2 − w2).

Flow Generated by Radial Flow Impellers: PIV Measurements and CFD Simulations

2004 ◽  
Vol 2 (1) ◽  
Author(s):  
Avinash Khopkar ◽  
Joella Aubin ◽  
C Rubio-Atoche ◽  
Catherine Xuereb ◽  
Nathalie Le Sauze ◽  
...  
Keyword(s):  
Low Pressure ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Rushton Turbine ◽  
Image Velocimetry ◽  
Trailing Vortices ◽  
Computational Fluid Dynamics Cfd ◽  
Improved Performance ◽  
Gas Liquid Flow ◽  
Experimental Findings

Particle image velocimetry (PIV) and computational fluid dynamics (CFD) have been used to investigate the single phase and gas-liquid flow generated by a Scaba SRGT turbine. The key details of the trailing vortices, the turbulent flow around the impeller blades and the accumulation of gas have been studied by using PIV measurements and CFD simulations. Both the experimental and numerical results show that the flow and the trailing vortices are not altered significantly upon gassing. The simulated results are generally in good agreement with the experimental findings. The CFD simulations also show that only small low-pressure regions exist behind the blades of the Scaba turbine compared with the very large low-pressure zones formed by the Rushton turbine. These results enable better understanding of the improved performance of the Scaba turbine for gas-liquid dispersions compared with the Rushton turbine.

PAPER PHYSICS. PIV measurements of flow through forming fabrics

2012 ◽  
Vol 27 (4) ◽  
pp. 783-789 ◽  
Author(s):  
Haiya Peng ◽  
Sheldon I. Green
Keyword(s):  
Test Section ◽  
Single Phase ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Flow Speed ◽  
Flow Loop ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Velocity Deviation ◽  
Flow Through

Abstract The three-dimensional velocity field in the single phase approach flow to a multiple layer woven forming fabric was measured using PIV. The measurements were conducted on a scaled-up model of a forming fabric in a water/glycerin flow loop. Each strand on the paper side of the model forming fabric had a filament diameter ( d) of 1 5 mm, and the flow loop test section was 3 1 0 mm squared, permitting the measurement of detailed velocity distributions over multiple strands of the fabric. The flow speed in the loop test section was varied to achieve screen Reynolds numbers between 12 and 6 5 . PIV measurements showed that when the distance t o the paper side of the fabric changes from 0.25d to 1 . 5d, the normalized ZD, CMD and MD velocity deviation decreases from 1 9 .7% to 4 .2%, 1 5 . 3 % to 1 .9% and 1 4 . 5 % t o 2 . 3 %, respectively; the ratio between maximum and minimum ZD velocity decreases from 3 .3 to 1 .2 . These findings indicate that the flow non-uniformity caused by the fabric weave is confined to a short distance above the fabric. CFD simulations of the same flow were consistent with the PIV measurements.

Numerical Simulation of Biodiesel Production Using Waste Cooking Oil

2013 ◽  
Author(s):  
A. K. M. Mohiuddin ◽  
Nabeel Adedapo Adeyemi
Keyword(s):  
Waste Cooking Oil ◽  
Reynolds Stress Model ◽  
Biodiesel Production ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Dissipation Model ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Values ◽  
Cfd Method

The goal of this work was to carry out transesterification using computational fluid dynamics (CFD) method and obtain yield comparable to experimental values. First of all, the single–phase flow field was simulated and compared with experimental data obtained by means of particle image velocimetry (PIV) measurements. The velocities calculated from the RSM approach agreed quite well with those from PIV. The CFD simulations of biodiesel production were performed using the Reynolds stress model (RSM) coupled with the eddy dissipation model (EDM). CFD analysis of biodiesel yield compared fairly well with the experimental results available.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

scholarly journals Stereoscopic PIV measurements using low-cost action cameras

2021 ◽  
Vol 62 (3) ◽  
Author(s):  
Theo Käufer ◽  
Jörg König ◽  
Christian Cierpka
Keyword(s):  
Continuous Wave ◽  
Low Cost ◽  
Frame Rate ◽  
Processing Scheme ◽  
Piv Measurements ◽  
Stereoscopic Piv ◽  
Cost Action ◽  
Image Velocimetry ◽  
Frequency Generator ◽  
Educational Applications

Abstract Recently, large progress was made in the development towards low-cost PIV (Particle Image Velocimetry) for industrial and educational applications. This paper presents the use of two low-cost action cameras for stereoscopic planar PIV. A continuous wave laser or alternatively an LED was used for illumination and pulsed by a frequency generator. A slight detuning of the light pulsation and camera frame rate minimizes systematic errors by the rolling shutter effect and allows for the synchronization of both cameras by postprocessing without the need of hardware synchronization. The setup was successfully qualified on a rotating particle pattern in a planar and stereoscopic configuration as well as on the jet of an aquarium pump. Since action cameras are intended to be used at outdoor activities, they are small, very robust and work autarkic. In conjunction with the synchronization and image pre-processing scheme presented herein, those cameras enable stereoscopic PIV in harsh environments and even on moving experiments. Graphic abstract

Effects of Multiple Impacts and Size Distribution of Particles on Erosion Predictions Using CFD

2007 ◽  
Author(s):  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirzai
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Target Material ◽  
Average Particle ◽  
Multiple Impacts ◽  
Cfd Simulations ◽  
Erosion Damage ◽  
Wide Range

Erosion equations are usually obtained from experiments by impacting solid particles entrained in a gas or liquid on a target material. The erosion equations are utilized in CFD (Computational Fluid Dynamics) models to predict erosion damage caused by solid particle impingements. Many erosion equations are provided in terms of an erosion ratio. By definition, the erosion ratio is the mass loss of target material divided by the mass of impacting particles. The mass of impacting particles is the summation of (particle mass × number of impacts) of each particle. In erosion experiments conducted to determine erosion equations, some particles may impact the target wall many times and some other particles may not impact the target at all. Therefore, the experimental data may not reflect the actual erosion ratio because the mass of the sand that is used to run the experiments is assumed to be the mass of the impacting particles. CFD and particle trajectory simulations are applied in the present work to study effects of multiple impacts on developing erosion ratio equations. The erosion equation as well as the CFD-based erosion modeling procedure is validated against a variety of experimental data. The results show that the effect of multiple impacts is negligible in air cases. In water cases, however, this effect needs to be accounted for especially for small particles. This makes it impractical to develop erosion ratio equations from experimental data obtained for tests with sand in water or dense gases. Many factors affecting erosion damage are accounted for in various erosion equations. In addition to some well-studied parameters such as particle impacting speed and impacting angle, particle size also plays a significant role in the erosion process. An average particle size is usually used in analyzing experimental data or estimating erosion damage cases of practical interest. In petroleum production applications, however, the size of sand particles that are entrained in produced fluids can vary over a fairly broad range. CFD simulations are also performed to study the effect of particle size distribution. In CFD simulations, particle sizes are normally distributed with the mean equaling the average size of interest and the standard deviation varying over a wide range. Based on CFD simulations, an equation is developed and can be applied to account for the effect of the particle size distribution on erosion prediction for gases and liquids.

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