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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.

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Electrohydrodynamic secondary flow in the electrostatic precipitator with spiked electrodes

Podliński J., Berendt A., Niewulis A., Mizeraczyk J.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 8

22-24

EN

In this work, the results of electrohydrodynamic (EHD) secondary flow measurements in an electrostatic precipitator (ESP) with one-sided spike electrodes are presented. The EHD secondary flow was measured for one-sided spike electrodes with the spike tips directed either upstream or downstream the primary flow. The results showed different flow patterns for different spike tips direction in respect to the primary flow direction. This secondary flow patterns can have meaningful influence on the ESP collection efficiency.

PL

W niniejszej pracy zaprezentowano wyniki pomiarów przepływu elektrohydrodynamicznego w elektrofiltrze z elektrodami ostrzowymi z ostrzami po jednej stronie. Pomiary wykonano dla elektrod skierowanych ostrzami w górę oraz w dół przepływu pierwotnego. Uzyskane wyniki prezentują różne struktury przepływu w elektrofiltrze dla różnych położeń elektrod ostrzowych. Różne struktury przepływu mogą powodować znaczne różnice w skuteczności odpylania elektrofiltru.

3

Zastosowanie tunelu powietrznego do badań konwekcyjnego odprowadzania ciepła z układów elektronicznych

Felczak M., Ostrowski B., Więcek B.

Elektronika : prace naukowe

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2004

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nr 9

107-124

PL

W artykule przedstawiono projekt tunelu powietrznego do badań chłodzenia konwekcyjnego układów elektronicznych. Projekt został zweryfikowany poprzez symulacje numeryczne wykonane za pomocą programu FLUENT. W dalszej części pracy przedstawiono metodą laserowego noża świetlnego. Wykorzystuje sieją do pomiaru prędkości przepływu powietrza w tunelu, który to pomiar jest niezbędny do wyznaczenia warunków chłodzenia. W ostatniej części pracy przedstawiony jest przykład zastosowania tunelu do badań odprowadzania ciepła w elektronice. Opisano i zbadano efekt śladu termicznego podczas chłodzenia konwekcyjnego układów elektronicznych.

EN

The article presents design of a low-speed wind tunnel for forced convective cooling investigations of electronic devices. Design method of the tunel is presented. Results are verified by numerical simulations completed with the Fluent software. Particle image velocimetry method (PIV) as one of the method proposed for air velocity measurements is presented. Velocity measurements during wind tunnel investigations are necessary to know electronic devices cooling conditions. In the last section of the article, an example of electronic cooling investigations for the designed wind tunnel, is presented. It illustates the importance of thermal wake effect during heat dissipation in electronics.