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Flow boiling in horizontal flattened tubes. 1. Two-phase frictional pressure drop results and model.

Author(s) : MORENO QUIBÉN J., CHENG L., SILVA LIMA R. J. da, et al.

Type of article: Article

Summary

Experiments of diabatic two-phase pressure drops in flow boiling were conducted in four horizontal flattened smooth copper tubes with two different heights of 2 and 3 mm. The equivalent diameters of the flat tubes are 8.6, 7.17, 6.25, and 5.3 mm. The working fluids are R22 and R410A, respectively. The test conditions are: mass velocities from 150 to 500 kg/m2.s, heat fluxes from 6 to 40 kW/m2 and saturation temperature of 5°C (reduced pressures p(r) are 0.12 for R22 and 0.19 for R410A). The experimental results of two-phase pressure drops are presented and analyzed. Furthermore, the predicted two-phase frictional pressure drops by the flow pattern based two-phase pressure drop model of Moreno Quibén and Thome using the equivalent diameters were compared to the experimental data. The model, however, underpredicts the flattened tube two-phase frictional pressure drop data. Therefore, correction to the annular flow friction factor was proposed for the flattened tubes and now the method predicts 83.7% of the flattened tube pressure drop data within ±30%. The model is applicable to the flattened tubes in the test condition range in the present study. Extension of the model to other conditions should be verified with experimental data. [Reprinted with permission from Elsevier. Copyright, 2009].

Details

  • Original title: Flow boiling in horizontal flattened tubes. 1. Two-phase frictional pressure drop results and model.
  • Record ID : 2009-1956
  • Languages: English
  • Source: International Journal of Heat and Mass Transfer - vol. 52 - n. 15-16
  • Publication date: 2009/07
  • DOI: http://dx.doi.org/10.1016/j.ijheatmasstransfer.2008.12.032

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