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Analyse de la performance des ailettes d'échangeurs de chaleur à microcanaux sous conditions sèches, humides et partiellement humides.

Fin performance analysis for microchannel heat exchangers under dry, wet and partial wet conditions.

Numéro : pap. 2205

Auteurs : HUANG L., BACELLAR D., AUTE V., et al.

Résumé

Numerical models for microchannel heat exchanger (MCHX) are favored in research and development process due to their cost effectiveness as opposed to prototype development and testing. One of the challenges in using MCHX in the stationary heating, ventilating, air-conditioning and refrigeration (HVAC&R) applications is the evaporator design. A literature survey suggests that there lacks a unified air-to-surface heat transfer modeling approach for MCHX, especially under dehumidifying condition with tube-to-tube heat conduction. In this research, we present a fin heat transfer model for MCHX operating under dry, wet and partial wet conditions. Typically, there are two boundary conditions for the fins in MCHX. The adiabatic fin tip boundary condition is applied to the extended fins on top and bottom of the heat exchanger. The proposed model also accounts for tube-to-tube conduction wherein the surface temperatures of the two tubes bounding the fin are fixed, known as prescribed temperature boundary condition The modeling approach is capable of locating the boundary between dry and wet surface if partial-wet condition appears. A finite volume approach is adopted in the proposed model where the fin is separated into segments in the air-flow direction. The model is verified against simulation results obtained using a commercially available Computational Fluid Dynamics (CFD) package. The variation of air-side heat transfer coefficient along the air flow direction is calculated from CFD. These coefficients are then plugged into each segment in the fin analysis model. The prediction of two-dimensional temperature field along the fin surface using the proposed finite volume approach agrees very well with the CFD predictions. It is also expected that using the proposed wet-fin and partially-wet fin model, the latent load prediction in evaporators will be improved. The proposed model can serve as one of the foundation to further enhance the heat transfer modeling in MCHX design and simulation tools.

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 : Fin performance analysis for microchannel heat exchangers under dry, wet and partial wet conditions.
  • Identifiant de la fiche : 30013335
  • Langues : Anglais
  • Source : 2014 Purdue Conferences. 15th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Date d'édition : 14/07/2014

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