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Natural convection around a horizontal cylinder - comparison of results from numerical model with PIV-measurements


Veröffentlichungsart
Beitrag auf Tagung

Fakultät/Einrichtung
Natur und Technik

Institutszugehörigkeit
Julius Robert Mayer - Institute for Energy Engineering
http://www.hs-bremen.de/internet/de/forschung/einrichtungen/jrmi/

Verfasser
Smolen, Slawomir, Prof. Dr.-Ing.
Baars, Albert, Prof. Dr.
Hoffmann, Florian, Dipl.-Ing. (FH)
Cieslinski, Janusz T., Prof. Dr.
Sawicka, Dorota, M.Sc.

Jahrgang
2018

Name(n), Titel
Smolen, S., Baars, A., Cieslinski, J.T., Sawicka, D., Hoffmann, F.,
Natural convection around a horizontal cylinder - comparison of results from numerical model with PIV-measurements

Weitere Informationen zur Veranstaltung
5. Internationale Konferenz
- Niedertemperatur- und Abwärmenutzung in kommunalen und industriellen Energieversorgungssystemen
- Abwärmerückgewinnung und –nutzung in Energieversorgungssystemen auf Schiffen

Veranstaltungsort
Hochschule Bremen, Neustadtswall 30, 28199 Bremen

Datum
October 2018

Anmerkung
Abstract:

Thermal energy storage plays a crucial role in heat recovery and contribute considerably in improving the performance of the thermal systems. Large volume sensible heat systems are promising technologies with low heat losses and attractive prices. In the SHS systems the dominating mechanism of the heat transfer is natural convection.
This paper presents the results of the numerical modeling of the natural convection heat transfer of ethylene glycol from a horizontal cylinder in rectangular geometry. Free convection of the fluid around a heated horizontal cylinder in a rectangular geometry was investigated for Rayleigh number ranging from 3∙104 to 3∙105 using numerical simulation. The fluid motion through the natural convective heat transfer was investigated experimentally with the Particle Image Velocimetry (PIV) technique in the rectangular setup made of acrylic glass (PMMA) with dimensions 160 mm x 160 mm x 500 mm, filled with the fluid to the level of 350 mm. The results of the PIV measurements were compared with the calculations made in the numerical simulation.
The results of numerical simulations show satisfactory agreement with predictions made by recognized Churchill and Chu’s correlation. In the numerical two regions of fluid’s motion inside of the computation domain can be noted. Below the horizontal cylinder the fluid is almost quiescent. Above the heated cylinder a free jet develops due to temperature induced density gradient. Recirculation domains appear in order to fulfill the continuity condition. The jet gets unstable and an irregular flow motion can be observed. Similar behavior of the fluid was observed during the PIV measurements.



 

 

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