Share

Refrigerant flow boiling heat transfer in parallel microchannels as a function of local vapour quality.

Author(s) : BERTSCH S. S., GROLL E. A., GARIMELLA S. V.

Type of article: Article

Summary

Flow boiling of refrigerant HFC-134a in a multi-microchannel copper cold plate evaporator is investigated. The heat transfer coefficient is measured locally for the entire range of vapour qualities starting from subcooled liquid to superheated vapour. The test piece contains 17 parallel, rectangular microchannels (0.762 mm wide) of hydraulic diameter 1.09 mm and aspect ratio 2.5. The design of the test facility is validated by a robust energy balance as well as a comparison of single-phase heat transfer coefficients with results from the literature. Results are presented for four different mass fluxes of 20.3, 40.5, 60.8, and 81.0 kg/m2.s, which correspond to refrigerant mass flow rates of 0.5-2.0 g/s, and at three different pressures 400, 550 and 750 kPa corresponding to saturation temperatures of 8.9, 18.7, and 29°C. The wall heat flux varies from 0 to 20 W/cm2 in the experiments. The heat transfer coefficient is found to vary significantly with refrigerant inlet quality and mass flow rate, but only slightly with saturation pressure for the range of values investigated. The peak heat transfer coefficient is observed for a vapour quality of approximately 20%. [Reprinted with permission from Elsevier. Copyright, 2008].

Details

  • Original title: Refrigerant flow boiling heat transfer in parallel microchannels as a function of local vapour quality.
  • Record ID : 2009-0054
  • Languages: English
  • Source: International Journal of Heat and Mass Transfer - vol. 51 - n. 19-20
  • Publication date: 2008/09

Links


See other articles in this issue (2)
See the source

Indexing