scholarly journals Flow Field Research of the Reciprocating Baffled Flocculation Tank

2020 ◽  
Vol 2 (1) ◽  
pp. 29
Author(s):  
Ying Xu ◽  
Yuebin Wu ◽  
Huan Liang ◽  
Qiang Sun
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Flow Field ◽  
Particle Image ◽  
Field Research ◽  
Hydraulic Characteristics ◽  
Flocculation Efficiency ◽  
Image Velocimetry ◽  
Hydraulic Conditions ◽  
The Standard Model

To research the reasons for the unsatisfactory hydraulic conditions of the reciprocating baffled flocculation tank, this paper investigates its flow field through PIV (Particle Image Velocimetry) laboratory experiment tests and numerical simulation. Three numerical schemes, the standard model, RNG model and realizable model, are calibrated and validated with the experimental data gained in this study. They are adopted for comparative study of their validity and accuracy for modeling the effect of the hydraulic characteristics of the flow field on flocculation. The best validated model is then applied to explain the reasons for the low flocculation efficiency and is applied to improve the structure of the reciprocating baffled flocculation tank.

Simulation and Experimental Investigations of Fiber Diameter of Spunbonding Nonwovens by Means of the Air Jet Flow Field Model

2010 ◽  
Vol 136 ◽  
pp. 5-9
Author(s):  
B. Zhao
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Particle Image ◽  
Field Model ◽  
Fiber Diameter ◽  
Jet Flow ◽  
Experimental Investigations ◽  
Air Velocity ◽  
Air Jet ◽  
Image Velocimetry

The air jet flow field models of spunbonding process are founded. It is simulated by means of the finite difference method. The numerical simulation computation results of distributions of the air velocity match quite well with the experimental data. The air drawing model of polymer is solved with the help of the distributions of the air velocity measured by a particle image velocimetry. The predicted filament fiber diameter agrees with the experimental data well.

Experimental Measurements and Numerical Simulations in Isothermal Turbulent Flows

2012 ◽  
Author(s):  
Florin G. Florean ◽  
Jeni A. Popescu ◽  
Ionut Porumbel ◽  
Cristian Carlanescu ◽  
Gheorghe Dumitrascu
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Particle Image Velocimetry ◽  
Bluff Body ◽  
Particle Image ◽  
Experimental Measurements ◽  
Combustion System ◽  
Gas Generator ◽  
Turbine Engine ◽  
Image Velocimetry

The paper presents Particle Image Velocimetry experimental measurements and an ANSYS CFX numerical simulation of the mean and fluctuating velocity field in a turbulent, isothermal flow downstream of a V-shaped bluff body flame stabilizer equipping a post-combustion system installed downstream of a Garrett 30-67 gas turbine engine. The post-combustion system used as experimental model is described in detail, and the main characteristics of the Garrett 30-67 gas generator are included in the paper. Also, the instrumentation used on the experimental rig, including the Particle Image Velocimetry equipment, is briefly described. The presence of a bluff body inside the high speed flow creates a re-circulating wake structure, clearly seen in the experimental data. In the near field, the re-circulating region’s length and width of are captured reasonably well by the numerical simulation, but the momentum rate transfer further downstream is over-predicted, as the grid resolution worsens. An overall over prediction of the axial velocity by the numerical simulation is noted by comparing the numerical simulation results to the experimental data, explained by an over estimated inlet velocity in the numerical simulation, provided by Particle Image Velocimetry experimental measurements in the free exhaust jet behind the gas generator, without the installation of the post-combustion system, thus neglecting the effect of the latter on the operating regime of the gas turbine engine.

scholarly journals Turbulent Flow Field around Horizontal Cylinders with Scour Hole

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 143 ◽  
Author(s):  
Nadia Penna ◽  
Francesco Coscarella ◽  
Roberto Gaudio
Keyword(s):  
Flow Field ◽  
Particle Image ◽  
Vertical Plane ◽  
Reynolds Stresses ◽  
Mixing Processes ◽  
Image Velocimetry ◽  
Hydraulic Conditions ◽  
Scour Hole ◽  
Scouring Process ◽  
Horizontal Cylinders

This study presents the results of an experimental investigation on the flow-structure interactions at scoured horizontal cylinders, varying the gap between the cylinder and the bed surface. A 2D Particle Image Velocimetry (PIV) system was used to measure the flow field in a vertical plane at the end of the scouring process. Instantaneous and ensemble-averaged velocity and vorticity fields, viscous and Reynolds stresses, and ensemble-averaged turbulence indicators were calculated. Longitudinal bed profiles were measured at the equilibrium. The results revealed that suspended and laid on cylinders behave differently from half-buried cylinders if subjected to the same hydraulic conditions. In the latter case, vortex shedding downstream of the cylinder is suppressed by the presence of the bed surface that causes an asymmetry in the development of the vortices. This implies that strong turbulent mixing processes occur downstream of the uncovered cylinders, whereas in the case of half-buried cylinders they are confined within the scour hole.

Rotor Blade-to-Blade Measurements Using Particle Image Velocimetry

1997 ◽  
Vol 119 (2) ◽  
pp. 176-181 ◽  
Author(s):  
D. Tisserant ◽  
F. A. E. Breugelmans
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Measurement Techniques ◽  
Axial Flow ◽  
Operating Conditions ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
Experimental Apparatus

The study of turbomachinery flow fields requires detailed experimental data. The rotating parts of turbomachines greatly limit the measurement techniques that can be used. Particle Image Velocimetry (PIV) appears to be a suitable tool to investigate the blade-to-blade flow in a rotor. The facility is a subsonic axial-flow compressor. The experimental apparatus enables the recording of a double-exposed photograph in a circumferential plane located at 85 percent of the blade height. The illumination plane has an axial direction and is provided by a pulsed ruby laser. The tracers used are submicron glycerine oil droplets. Data are processed by Young’s fringes method. Measurements were performed at 3000, 4500, and 6000 rpm with velocities in the range of 30 to 70 m/s. Steady operating conditions are chosen in such a way that the effect of radial velocity on PIV measurements can be neglected. Experimental problems encountered included homogeneous seeding of the flow field and laser light scattering from blade surfaces. The uncertainty affecting the velocity determination corresponds to 2 percent of the measured value. For a given set of operating conditions, 10 PIV pictures are recorded. The periodic flow field is approximated by averaging the experimental data point by point. Upstream and downstream velocity triangles are confirmed by measurements obtained from pressure probes. PIV measurement results were found to be similar to those of a blade-to-blade potential-flow calculation.

scholarly journals Experimental Validation of Falling Liquid Film Models: Velocity Assumption and Velocity Field Comparison

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1205
Author(s):  
Ruiqi Wang ◽  
Riqiang Duan ◽  
Haijun Jia
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Velocity Field ◽  
Experimental Validation ◽  
Particle Image ◽  
Velocity Fields ◽  
Number Range ◽  
Comparison Results ◽  
Image Velocimetry ◽  
Experimental Particle

This publication focuses on the experimental validation of film models by comparing constructed and experimental velocity fields based on model and elementary experimental data. The film experiment covers Kapitza numbers Ka = 278.8 and Ka = 4538.6, a Reynolds number range of 1.6–52, and disturbance frequencies of 0, 2, 5, and 7 Hz. Compared to previous publications, the applied methodology has boundary identification procedures that are more refined and provide additional adaptive particle image velocimetry (PIV) method access to synthetic particle images. The experimental method was validated with a comparison with experimental particle image velocimetry and planar laser induced fluorescence (PIV/PLIF) results, Nusselt’s theoretical prediction, and experimental particle tracking velocimetry (PTV) results of flat steady cases, and a good continuity equation reproduction of transient cases proves the method’s fidelity. The velocity fields are reconstructed based on different film flow model velocity profile assumptions such as experimental film thickness, flow rates, and their derivatives, providing a validation method of film model by comparison between reconstructed velocity experimental data and experimental velocity data. The comparison results show that the first-order weighted residual model (WRM) and regularized model (RM) are very similar, although they may fail to predict the velocity field in rapidly changing zones such as the front of the main hump and the first capillary wave troughs.

Endoscopic 2D particle image velocimetry (PIV) flow field measurements in IC engines

2002 ◽  
Vol 33 (6) ◽  
pp. 794-800 ◽  
Author(s):  
U. Dierksheide ◽  
P. Meyer ◽  
T. Hovestadt ◽  
W. Hentschel
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Field Measurements ◽  
Image Velocimetry ◽  
Ic Engines

scholarly journals Manifold reduction techniques for the comparison of crank angle-resolved particle image velocimetry (PIV) data and Reynolds-averaged Navier-Stokes (RANS) simulations in a spark ignition direct injection (SIDI) engine

2021 ◽  
pp. 146808742110131
Author(s):  
Xiaohang Fang ◽  
Li Shen ◽  
Christopher Willman ◽  
Rachel Magnanon ◽  
Giuseppe Virelli ◽  
...  
Keyword(s):  
Flow Field ◽  
Particle Image ◽  
Direct Injection ◽  
Linear Manifold ◽  
Main Flow ◽  
Navier Stokes ◽  
Reduction Techniques ◽  
Image Velocimetry ◽  
Manifold Reduction ◽  
Relevance Index

In this article, different manifold reduction techniques are implemented for the post-processing of Particle Image Velocimetry (PIV) images from a Spark Ignition Direct Injection (SIDI) engine. The methods are proposed to help make a more objective comparison between Reynolds-averaged Navier-Stokes (RANS) simulations and PIV experiments when Cycle-to-Cycle Variations (CCV) are present in the flow field. The two different methods used here are based on Singular Value Decomposition (SVD) principles where Proper Orthogonal Decomposition (POD) and Kernel Principal Component Analysis (KPCA) are used for representing linear and non-linear manifold reduction techniques. To the authors’ best knowledge, this is the first time a non-linear manifold reduction technique, such as KPCA, has ever been used in the study of in-cylinder flow fields. Both qualitative and quantitative studies are given to show the capability of each method in validating the simulation and incorporating CCV for each engine cycle. Traditional Relevance Index (RI) and two other previously developed novel indexes: the Weighted Relevance Index (WRI) and the Weighted Magnitude Index (WMI), are used for the quantitative study. The results indicate that both POD and KPCA show improvements in capturing the main flow field features compared to ensemble-averaged PIV experimental data and single cycle experimental flow fields while capturing CCV. Both methods present similar quantitative accuracy when using the three indexes. However, challenges were highlighted in the POD method for the selection of the number of POD modes needed for a representative reconstruction. When the flow field region presents a Gaussian distribution, the KPCA method is seen to provide a more objective numerical process as the reconstructed flow field will see convergence with an increasing number of modes due to its usage of Gaussian properties. No additional criterion is needed to determine how to reconstruct the main flow field feature. Using KPCA can, therefore, reduce the amount of analysis needed in the process of extracting the main flow field while incorporating CCV.

Flow field analysis in a compliant acinus replica model using particle image velocimetry (PIV)

2010 ◽  
Vol 43 (6) ◽  
pp. 1039-1047 ◽  
Author(s):  
Emily J. Berg ◽  
Jessica L. Weisman ◽  
Michael J. Oldham ◽  
Risa J. Robinson
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Field Analysis ◽  
Image Velocimetry ◽  
Flow Field Analysis

scholarly journals AN ATHEROSCLEROTIC CORONARY ARTERY PHANTOM FOR PARTICLE IMAGE VELOCIMETRY

2011 ◽  
Author(s):  
Jean Brunette ◽  
Rosaire Mongrain ◽  
Rosaire Mongrain ◽  
Adrian Ranga ◽  
Adrian Ranga ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Heart Attack ◽  
Computational Models ◽  
Particle Image ◽  
Flow Analysis ◽  
Novel Technique ◽  
Image Velocimetry ◽  
Inflammatory Processes ◽  
Injection Molded

Myocardial infarction, also known as a heart attack, is the single leading cause of death in North America. It results from the rupture of an atherosclerotic plaque, which occurs in response to both mechanical stress and inflammatory processes. In order to validate computational models of atherosclerotic coronary arteries, a novel technique for molding realistic compliant phantom featuring injection-molded inclusions and multiple layers has been developed. This transparent phantom allows for particle image velocimetry (PIV) flow analysis and can supply experimental data to validate computational fluid dynamics algorithms and hypothesis.

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