hig.sePublikationer
Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Investigation of design parameters for an air supply device based on wall confluent jets
Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Linköpings universitet.
Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Linköpings universitet.ORCID-id: 0000-0003-3472-4210
2015 (Engelska)Artikel i tidskrift (Övrigt vetenskapligt) Submitted
Ort, förlag, år, upplaga, sidor
2015.
Nyckelord [en]
Wall confluent jets supply device, Numerical predictions, Parametric studies, Ventilation performance, Ventilation efficiency, Thermal comfort
Nationell ämneskategori
Energiteknik
Identifikatorer
URN: urn:nbn:se:hig:diva-19372OAI: oai:DiVA.org:hig-19372DiVA, id: diva2:814060
Tillgänglig från: 2015-05-26 Skapad: 2015-05-26 Senast uppdaterad: 2018-03-13Bibliografiskt granskad
Ingår i avhandling
1. A Ventilation Strategy Based on Confluent Jets: An Experimental and Numerical Study
Öppna denna publikation i ny flik eller fönster >>A Ventilation Strategy Based on Confluent Jets: An Experimental and Numerical Study
2015 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

This study presents air distribution systems that are based on confluent jets; this system can be of interest for the establishment of indoor environments, to fulfill the goals of indoor climate and energy-efficient usage. The main objective of this study is to provide deeper understanding of the flow field development of a supply device that is designed based on wall confluent jets and to investigate the ventilation performance by experimental and numerical methods. In this study, the supply device can be described as an array of round jets on a flat surface attached to a side wall. Multiple round jets that issue from supply device apertures are combined at a certain distance downstream from the device and behave as a united jet or so-called confluent jets. Multiple round jets that are generated from the supply device move downward and are attached to the wall at the primary region, due to the Coanda effect, and then they become wall confluent jets until the floor wall is reached. A wall jet in a secondary region is formed along the floor after the stagnation region.

The characteristics of the flow field and the ventilation performance of conventional wall confluent jets and modified wall confluent jets supply devices are investigated experimentally in an office test room. The study of the modified wall confluent jets is intended to improve the efficiency of the conventional one while maintaining acceptable thermal comfort in an office environment. The results show that the modified wall confluent jets supply device can provide acceptable thermal comfort for the occupant with lower airflow rate compared to the conventional wall confluent jets supply device.

Numerical predictions using three turbulence models (renormalization group (RNG k– ε), realizable (Re k– ε), and shear stress transport (SST k– ω) are evaluated by measurement results. The computational box and nozzle plate models are used to model the inlet boundary conditions of the nozzle device. In the isothermal study, the wall confluent jets in the primary region and the wall jet in the secondary region, when predicted by the three turbulence models, are in good agreement with the measurements. The non-isothermal validation studies show that the SST k– ω model is slightly better at predicting the wall confluent jets than the other two models. The SST k– ω model is used to investigate the effects of the nozzle diameter, number of nozzles, nozzle array configuration, and inlet discharge height on the ventilation performance of the proposed wall confluent jets supply device. The nozzle diameter and number of nozzles play important roles in determining the airflow pattern, temperature field, and draught distribution. Increased temperature stratification and less draught distribution are achieved by increasing the nozzle diameter and number of nozzles. The supply device with smaller nozzle diameters and fewer nozzles yields rather uniform temperature distribution due to the dominant effect of mixing. The flow behavior is nearly independent of the inlet discharge height for the studied range.

The proposed wall confluent jets supply device is compared with a mixing supply device, impinging supply device and displacement supply device. The results show that the proposed wall confluent jets supply device has the combined behavior of both mixing and stratification principles. The proposed wall confluent jets supply device provides better overall ventilation performance than the mixing and displacement supply devices used in this study.

This study covers also another application of confluent jets that is based on impinging technology. The supply device under consideration has an array of round jets on a curve. Multiple jets issue from the supply device aperture, in which the supply device is positioned vertically and the jets are directed against a target wall. The flow behavior and ventilation performance of the impinging confluent jets supply device is studied experimentally in an industrial premise. The results show that the impinging confluent jets supply device maintains acceptable thermal comfort in the occupied zone by creating well-distributed airflow during cold and hot seasons.

Ort, förlag, år, upplaga, sidor
Linköping: Linköping University Electronic Press, 2015. s. 78
Serie
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1671
Nyckelord
Multiple interacting jets, round jets, confluent jets, wall jet, ventilation strategy, air distribution system, air supply device, ventilation performance, thermal comfort, energy-saving potential, measurement, numerical predictions, RANS turbulence models, renormalization group (RNG k– ε), realizable (Re k– ε), and shear stress transport (SST k– ω)
Nationell ämneskategori
Energiteknik
Identifikatorer
urn:nbn:se:hig:diva-19369 (URN)10.3384/diss-diva-117442 (DOI)978-91-7519-063-1 (ISBN)
Disputation
2015-05-29, ACAS, Hus A, Campus Valla, 10:15 (Engelska)
Opponent
Handledare
Tillgänglig från: 2015-05-26 Skapad: 2015-05-26 Senast uppdaterad: 2018-03-13Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Personposter BETA

Janbakhsh, SetarehMoshfegh, Bahram

Sök vidare i DiVA

Av författaren/redaktören
Janbakhsh, SetarehMoshfegh, Bahram
Av organisationen
Energisystem
Energiteknik

Sök vidare utanför DiVA

GoogleGoogle Scholar

urn-nbn

Altmetricpoäng

urn-nbn
Totalt: 271 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf