Wyniki wyszukiwania - BazTech

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Experimental and numerical flow analysis through arteries with stent using particle image velocimetry and computational fluid dynamics method

Tomaszewski Michal, Sybilski Kamil, Baranowski Pawel, Malachowski Jerzy

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 2

740--751

EN

In the paper, an experimental and numerical flow through various kind of arteries is considered. The flow analyses are carried out on the research set up using Particle Image Velocimetry Method (PIV). The individual components of the research set up are discussed and the measurement methodology is explained. The work consists of two parts. The first one is focused on modelling numerical simulation of the stent installation procedure using an expandable balloon and the flow domain design methodology is described. In the final part, an experimental flow test on an artificial silicone vessel (diameter 3.2 mm) with a stent is performed. The results of the experimental tests are compared with a corresponding numerical simulation. The paper presents numerical simulation for two different flow domains and the results obtained from the experimental tests. In both, the experimental tests and numerical simulation, the pulsatile time dependent flow and pressure characteristic are used. Hemodynamic parameters such as the time average wall shear stress (TAWSS) and velocity vector distribution are analysed. The flow was studied at four Reynolds number values (1223; 2257; 3198; 3762) for the straight vessel and at two values for the vessel containing a stent (1223, 2257). A diameter of the vessel was 3.2 mm. Pulsating blood flow based on the data from the experimental test was analysed. During the numerical simulation it was verified which regions of the vessel had TAWSS values below 0.4 Pa. A satisfactory correlation between outcomes of the numerical simulation and the experimental test was obtained. The flow analysis is conducted in ANSYS Fluent software. Additionally, the methodology for defining the velocity profile at the entrance is presented, in order to form the velocity profile in the first step of analysed cases. The study shows possibility to create a new research set up capable of testing various clinical cases of varying pressure values in the setup, or testing the effects of vessel geometrical changes, which allows observing an influence of those parameters on the fluid flow characteristic. As the analysis for the stent has shown, the regions of low TAWSS values are located in a close proximity to the stent struts.

2

Studium ruchu cieczy w aparacie zbiornikowym z wirującą tarczą

Suchecki W.

Inżynieria i Aparatura Chemiczna

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2006

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Nr 6s

228-229

EN

Auxiliary rotating devices influence the liquid flow in a process equipment unit, therefore affecting heat and mass transfer. This study is devoted to liquid movement in a vessel under influence of the rotating disk placed at free liquid surface. Experimental data were collected and compared with the results of numerical . simulations.

3

Image processing and statistical analysis of the signals in gas-liquid flows research

Ulbrich R., Zając D.

Turbulence : international journal

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2005

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Vol. 11

141-148

EN

The aim of this work is an experimental hydrodynamic analysis of two-phase gas--liquid flow carried in bubble column with the usage of digital image processing method (DIP) connected with statistical analysis. The measurement signals were recorded by high speed CMOS camera images sequences of the two phase flow. The results of the image processing and statistic analysis were flow regimes identification and velocity determination.

4

Experimental analysis of granular material flows using the technique of digital particle image velocimetry

Sielamowicz I.

Engineering Transactions

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2005

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Vol. 53, iss. 2

197-229

EN

This paper presents the results of experiments of granular flows carried out for two configurations - in a plane model with vertical walls and in a wedge-shaped model. Both models were built of plexiglass and replicate the geometry of a silo. The flow processes of central and eccentric discharge were recorded by a high resolution camera (SensiCam) through the transparent walls of the models. PIV measurements allow to obtain the following data of the flow: the plug flow zone evolution, velocity magnitude contours, velocity fields, velocity distributions on certain levels in the models, traces of individual particles. Local deformations and stresses in the material may be also determined. The models were filled in a natural way through a pipe placed vertically in the symmetry axis above the models or through a sieve. In the case of the plane model, three cases of eccentric flows were investigated. Dynamic behaviour of the flowing materials recorded by the new measurement technique DPIV, commonly used in fluid mechanics, now applied for granular material flows, is analyzed. Uniform and repeatable packing of the materials with no particle segregation was obtained. Three different grain types were used in the experiments (amaranthus, flax-seed and buckwheat). These grains represent different physical properties and exhibit the phenomenon of static electricity of the materials when flowing and sliding over plexiglass.

5

Metoda korekty wykresów pól prędkości w cyfrowej anemometrii obrazowej

Suchecki W., Alabrudziński S.

Inżynieria i Aparatura Chemiczna

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2003

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Nr 3

14-20

PL

Zrealizowana praca miała na celu opracowanie i opanowanie metody korekty wykresów pól prędkości otrzymanych dzięki cyfrowej anemometrii obrazowej. Opracowano algorytm mający na celu identyfikację wektorów błędnych oraz zastąpienie ich wektorami uśrednionymi. Na podstawie algorytmu napisano program komputerowy (dla systemu Linux) oraz przeprowadzono szereg obliczeń celem weryfikacji. Uzyskane wyniki pozwoliły stwierdzić przydatność zastosowanych metod oraz dostarczyły wiele istotnych i cennych informacji mogących znacznie udoskonalić metodę dla przepływów ustalonych i quasi-ustalonych

EN

The aim of this work was to elaborate and acquire proficiency in the correction method of velocity fields diagrams obtained by digital image anemometry. The algorithm for false vectors identification and their replacement by average vectors was determined. On the basis of this algorithm the software (for the Linux system) was written and a number of verifying calculations were carried out. The results obtained enabled one to confirm usability of the method. They were also a source of valuable information how to improve the method for steady state and quasi—steady state flows.

6

Metoda analizy pola prędkości z uwzględnieniem istnienia dużych obiektów w przepływie

Suchecki W., Alabrudziński S.

Inżynieria i Aparatura Chemiczna

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2003

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Nr 5

6-13

PL

Celem pracy było opracowanie sposobu pomiaru pól prędkości w przepływach indukowanych opadaniem lub wznoszeniem się cząstek stałych lub pęcherzy gazowych w cieczy. Zaprojektowano stanowisko pomiarowe, opracowano algorytmy analizy danych pomiarowych (oparte po części na metodzie PIV) i realizujące je programy komputerowe. Wykonano szereg badań eksperymentalnych w celu przetestowania i znalezienie ograniczeń opracowanej metody.

EN

The aim of the work was the elaboration of a measuring method of velocity fields in flows induced by falling down or rising up solid particles or gas bubbles in liquid. The experimental set-up bas been designed, algorithms for experimental data analysis based on the PTV method and appropriate computer software have been prepared. The experimental researches have been carried out with the purpose of testing and discovering restrictions of the method.