Flow structures in a swirl flow - vortex breakdown condition

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23640%2F18%3A43954225" target="_blank" >RIV/49777513:23640/18:43954225 - isvavai.cz</a>

Výsledek na webu

<a href="http://hdl.handle.net/11025/34730" target="_blank" >http://hdl.handle.net/11025/34730</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1742-6596/1045/1/012031" target="_blank" >10.1088/1742-6596/1045/1/012031</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Flow structures in a swirl flow - vortex breakdown condition

Popis výsledku v původním jazyce

This paper presents an experimental and numerical analysis of swirl flow in a circular tube. Swirl flow is important for technical and natural processes, where high heat transfer and good fluid mixing are needed. Flow and vortex structures respecting redistribution of momentum and possible occurrence of vortex breakdown are taken into account. The swirl flow is analysed experimentally by the measurement of the velocity field using Particle Image Velocimetry (PIV) and numerically via the commercial CFD code ANSYS CFX. Three cases are investigated: laminar flow regime (Re = 1,000), intermediate flow regime (Re = 2,000), and turbulent flow regime (Re = 5,000). The redistribution of the velocity field and the decrease of the swirl strength towards the outlet are shown. This redistribution affects the Reynolds number. Concerning the Rossby number, the occurrence of vortex breakdown in the swirl flow is determined. It is shown that the vortex breakdown takes place in the flow with higher Reynolds numbers, where an axial backflow may occur. Changes of the Reynolds numbers Re_phi and Re_z along the tube length also confirm this statement. Furthermore, a thermodynamic perspective of vortex breakdown phenomena is presented.

Název v anglickém jazyce

Flow structures in a swirl flow - vortex breakdown condition

Popis výsledku anglicky

This paper presents an experimental and numerical analysis of swirl flow in a circular tube. Swirl flow is important for technical and natural processes, where high heat transfer and good fluid mixing are needed. Flow and vortex structures respecting redistribution of momentum and possible occurrence of vortex breakdown are taken into account. The swirl flow is analysed experimentally by the measurement of the velocity field using Particle Image Velocimetry (PIV) and numerically via the commercial CFD code ANSYS CFX. Three cases are investigated: laminar flow regime (Re = 1,000), intermediate flow regime (Re = 2,000), and turbulent flow regime (Re = 5,000). The redistribution of the velocity field and the decrease of the swirl strength towards the outlet are shown. This redistribution affects the Reynolds number. Concerning the Rossby number, the occurrence of vortex breakdown in the swirl flow is determined. It is shown that the vortex breakdown takes place in the flow with higher Reynolds numbers, where an axial backflow may occur. Changes of the Reynolds numbers Re_phi and Re_z along the tube length also confirm this statement. Furthermore, a thermodynamic perspective of vortex breakdown phenomena is presented.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20303 - Thermodynamics

Projekt

<a href="/cs/project/LO1402" target="_blank" >LO1402: CENTEM+</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Journal of Physics: Conference Series

ISBN

—

ISSN

1742-6588

e-ISSN

1742-6596

Počet stran výsledku

9

Strana od-do

"NESTRÁNKOVÁNO"

Název nakladatele

IOP Publishing Ltd.

Místo vydání

Bristol, UK

Místo konání akce

Miskolc-Lillafüred, Maďarsko

Datum konání akce

2. 10. 2017

Typ akce podle státní příslušnosti

EUR - Evropská akce

Kód UT WoS článku

—