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Validation expérimentale d'un éjecteur prototype conçu pour réduire les pertes de laminage lors du fonctionnement d'un système au R-744 transcritique.

Experimental validation of a prototype ejector designed to reduce throttling losses encountered in transcritical R-744 system operation.

Auteurs : ELBEL S., HRNJAK P.

Type d'article : Article, Article de la RIF

Résumé

This study presents experimental results obtained from a transcritical R-744 system using a refrigerant ejector. The results were compared to that of a conventional system with an expansion valve. For the test conditions considered, the cooling capacity and COP simultaneously improved by up to 8 and 7%, respectively. Experiments were analyzed to quantitatively assess the effects on system performance as a result of changes in basic ejector dimensions such as motive nozzle and diffuser sizing. Small angles of 5° yielded best results for the static pressure recovery of the high-speed two-phase flow entering the diffuser. Experiments confirmed that like in a conventional transcritical R-744 system with expansion valve, the high-side pressure control integrated into the ejector could be used to maximize the system performance. Numerical simulation results helped identifying this basic trend. Due to difficulties in the ejector throat pressure measurements, a more practical performance metric was introduced in order to quantify overall ejector efficiencies. According to this definition, the prototype ejector was able to recover up to 14.5% of the throttling losses.

Documents disponibles

Format PDF

Pages : 411-422

Disponible

  • Prix public

    20 €

  • Prix membre*

    Gratuit

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

Détails

  • Titre original : Experimental validation of a prototype ejector designed to reduce throttling losses encountered in transcritical R-744 system operation.
  • Identifiant de la fiche : 2008-0569
  • Langues : Anglais
  • Source : International Journal of Refrigeration - Revue Internationale du Froid - vol. 31 - n. 3
  • Date d'édition : 05/2008

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