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Analyse d'un écoulement de jet à faible nombre de Reynolds à partir d'une tuyère à jets dans des applications de chauffage, de ventilation et de conditionnement d'air.

Analysis of a low Reynolds jet flow from a notched orifice jet for HVAC applications.

Numéro : pap. 79

Auteurs : GREFFET R., MESLEM A., NASTASE I.

Résumé

The flow in the initial region of a notched orifice jet is experimentally analyzed and compared to a circular orifice jet. The equivalent diameter (De) of each orifice is 10 mm. The initial Reynolds number based on De was around 800 for both jets. Flows exploration has been achieved using flow visualization, Particle Image Velocimetry, Laser Doppler Anemometry as well as Hot-Wire Anemometry. The aimed applications are mixing ventilation and personalized ventilation (PV). Our previous investigation of elementary orifice cross-shaped jet and its integration in the design of innovative air diffusion terminal units confirm the advantage of passive mixing control using lobed orifices. The present geometry manipulation extends the passive control to rectangular jets sometimes preferred in the design of HVAC terminal units. The axis-switching phenomenon observed earlier in the cross-shaped jet, disappears in the notched orifice jet. The streamwise structures that develop in orifice troughs do not modify the overall transverse direction of the notched jet. This can be an advantage in PV which must provide a jet flow that covers the breathing zone of the user. Velocity fields show that the jet potential core length is shorter in the notched orifice jet compared to the circular orifice jet. The potential core length is quantified to about 2De in the notched jet and to 5De in the reference circular jet. This is due to a larger ambient-air entrainment in the former with comparison to that in the latter.

Documents disponibles

Format PDF

Pages : 10 p.

Disponible

  • Prix public

    20 €

  • Prix membre*

    15 €

* meilleur tarif applicable selon le type d'adhésion (voir le détail des avantages des adhésions individuelles et collectives)

Détails

  • Titre original : Analysis of a low Reynolds jet flow from a notched orifice jet for HVAC applications.
  • Identifiant de la fiche : 30008580
  • Langues : Anglais
  • Source : Clima 2013. 11th REHVA World Congress and 8th International Conference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings.
  • Date d'édition : 16/06/2013

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