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Non-uniform airflow and thermal performances of an evaporator.

Flux d'air non-uniforme et performances thermiques d'un évaporateur.

Author(s) : TIMONEY D. J., RYAN A. M.

Type of article: Article

Summary

This article presents the experimental results obtained with entering uniform and non-uniform airflows, crossing an R134a monocircuit evaporator comprising a bundle of finned tubes. The reference case concerns uniform airflow provided by a test tunnel, and non-uniform flow provided, either by an axial ventilator inducing the flow by means of long or short ducts. The tests were undertaken on a large range of refrigerant flows for each configuration, but with a constant total airflow and mean speed. The airflow and the forms of turbulence at the evaporator inlet were recorded using a hot wire anemometer. The experimental results clearly demonstrate the considerable effects on the evaporator's thermal performances, which can involve the turbulence effects created by non-uniform airflow. The relative performances were compared on the basis of a global transfer coefficient, calculated from a simplified definition of the total temperature difference. Non-uniform flow with a high turbulence level, generated by the centrifugal ventilator, involves a significant increase (13 to 22%) in the thermal transfer performances, for given airflows and refrigerant flows. Other non-uniform flows generated by an axial ventilator with a short entry duct involved weaker increase.

Details

  • Original title: Flux d'air non-uniforme et performances thermiques d'un évaporateur.
  • Record ID : 2004-2150
  • Languages: French
  • Source: Rev. gén. Froid - vol. 94 - n. 1040
  • Publication date: 2004/01
  • Document available for consultation in the library of the IIR headquarters only.

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