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.

Using CFD to Improve Aero-Engine Air/Oil Separator Design

2002 ◽  
Author(s):  
Carol Eastwick ◽  
Stephen Hibberd ◽  
Kathy Simmons ◽  
Yi Wang ◽  
Ian Care ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Gas Turbine ◽  
Particle Image ◽  
Environmental Concern ◽  
Labyrinth Seals ◽  
Two Phase ◽  
Turbine Engine ◽  
Image Velocimetry ◽  
Aero Engine

Within the transmission system of a commercial gas turbine engine the lubrication and cooling of shaft bearings is performed by oil injected into bearing chambers that are typically sealed with air-pressurised labyrinth seals. The subsequent air/oil mixture is scavenged from the bearing chamber with the oil being re-used, whilst the air is discharged overboard via an air/oil separator. Efficiency of separators is becoming a high priority to industry, with any loss of oil an environmental concern. To help improve the design of separators a computational model was created of an existing design and coupled two-phase CFD calculations were performed. A limited amount of experimental data, collected by particle image velocimetry (PIV) was available for validation.

scholarly journals Experimental investigation of flow behind a cube for moderate Reynolds numbers

2014 ◽  
Vol 750 ◽  
pp. 73-98 ◽  
Author(s):  
L. Klotz ◽  
S. Goujon-Durand ◽  
J. Rokicki ◽  
J. E. Wesfreid
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Particle Image Velocimetry ◽  
Bluff Body ◽  
Particle Image ◽  
Reynolds Numbers ◽  
Laser Induced Fluorescence ◽  
Basic Flow ◽  
Water Tunnel ◽  
Image Velocimetry

AbstractThe wake behind a cube with a face normal to the flow was investigated experimentally in a water tunnel using laser induced fluorescence (LIF) visualisation and particle image velocimetry (PIV) techniques. Measurements were carried out for moderate Reynolds numbers between 100 and 400 and in this range a sequence of two flow bifurcations was confirmed. Values for both onsets were determined in the framework of Landau’s instability model. The measured longitudinal vorticity was separated into three components corresponding to each of the identified regimes. It was shown that the vorticity associated with a basic flow regime originates from corners of the bluff body, in contrast to the two other contributions which are related to instability effects. The present experimental results are compared with numerical simulation carried out earlier by Saha (Phys. Fluids, vol. 16, 2004, pp. 1630–1646).

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.

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.

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.

Numerical Simulation of Dynamic Process under Low Pressure Casting Based on Two Phase Flow

2015 ◽  
Vol 727-728 ◽  
pp. 358-361
Author(s):  
Shan Guang Liu ◽  
Fu Yang Cao ◽  
Xin Yi Zhao ◽  
Yan Dong Jia ◽  
Zhi Liang Ning ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Mold Filling ◽  
Phase Flow ◽  
Pressure Casting ◽  
Filling Process ◽  
Two Phase ◽  
Image Velocimetry ◽  
Low Pressure Casting

It has been proved that the mold filling under low pressure casting can be described by the second order nonlinear differential equations characterized by damping oscillations. To obtain higher accuracy of the velocity field, the mold filling process with damping oscillations should be considered. A computational model taking the liquid level droping in the crucible into account based on two phase flow for filling process of damping oscillations is presented in this paper. Hydraulic simulation with the particle image velocimetry was adopted to verify the numerical simulation result. It is proved that the nemuerical simulation results used the presented model perfecly match with the particle image velocimetry results. Liquid level droping in crucible is the main reason for damping oscillations in mold filling. Velocity oscilations can be eliminated when the melt flow across a sudden expansion section. The detailed flow field based on the presented model can provide guidance to optimize the process parameters.

scholarly journals Development of the optical electronic setup for carrying out measurements by multicolor Particle Image Velocimetry

2021 ◽  
Vol 2127 (1) ◽  
pp. 012018
Author(s):  
S S Usmanova ◽  
N M Skornyakova ◽  
Yu S Belov ◽  
M V Sapronov ◽  
A V Kuchmenko ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Computer Model ◽  
Vortex Structure ◽  
Test Object ◽  
3D Model ◽  
Particle Image ◽  
Velocity Fields ◽  
Laboratory Sample ◽  
Image Velocimetry

Abstract The paper is devoted to development of the optical electronic setup for carrying out measurements by multicolor particle image velocimetry. The main advantage of this method is the ability to visualize vector velocity fields in several planes simultaneously. As a result a 3D model of a setup was developed, a laboratory sample was assembled and series of testing experiments were performed. As a test object, vortex structure formed by a chemical stirrer in a cuvette with liquid has been considered. The experimental data were compared with the computer model developed in SolidWorks and FlowVision software.

Some Experience on Particle Image Velocimetry of Near-Wall Shear Layers at Subsonic Velocities

2010 ◽  
Vol 5 (2) ◽  
pp. 55-68
Author(s):  
Andrey V. Boiko Boiko ◽  
Vasily N. Gorev ◽  
Aleksandr V. Dovgal ◽  
Aleksandr M. Sorokin ◽  
Hein Stefan ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Shear Layers ◽  
Linear Instability ◽  
Wind Tunnel Testing ◽  
Mean Velocity ◽  
Separating Flow ◽  
Image Velocimetry ◽  
Near Wall

Experimental data on linear instability of the laminar separating flow and mean velocity characteristics of the turbulent boundary layer are reported. The results are obtained through wind-tunnel testing of Particle Image Velocimetry (PIV) performed at DLR, Goettingen. Details of the method, as applied to the above problems of fluid mechanics, are considered. The present findings seem helpful during experimental work on subsonic near-wall layers, when focusing on their instantaneous and time-mean velocity characteristics.

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