Prediction of heat transfer coefficient in annular flow regime for flow boiling in a horizontal micro tube at a uniform heat flux

Amen Younes, Lyes Kadem, Ibrahim Hassan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

An analytical model for predicting heat transfer in annular flow regime for saturated flow boiling in a horizontal micro-tube subjected to a uniform heat flux has been developed based on one-dimensional separated flow model. Four main parameters have been considered, namely, vapor velocity, liquid film velocity, liquid film thickness, and the local pressure. Liquid film evaporation has been considered as a dominant heat transfer mechanism in the annular flow regime. Based on Taylors' law, the initial value of the liquid film thickness at the onset of annular flow is estimated by employing the proper correlations available in literature. The main model equations obtained have been solved numerically based on explicit Runge-Kutta method. More than 420 two-phase heat transfer data points of annular flow regime for various working fluids, R134a and CO2 have been collected for the model validation. The data points were recorded for round macro and micro single horizontal channels with a range of inner diameter of 0.244 mm ≤ Dh ≤3.64 mm, and a heated length to diameter ratio of 100 ≤(Lh/Dh/) ≤ 1300. The range of liquid to vapor density ratios is 6.37 ≤(ρfg) ≤ 62.34. The model was tested for equivalent Reynolds numbers within the range of 1,130 ≤ Reeq ≤ 55,260. In the scope of annular flow regime, the present model predicted well the collected heat transfer data with a mean absolute error (MAE) of 26.80 %.

Original languageEnglish
Title of host publication2nd International Conference on Fluid Flow, Heat and Mass Transfer, FFHMT 2015
PublisherAvestia Publishing
ISBN (Print)9781927877111
Publication statusPublished - 1 Jan 2015
Event2nd International Conference on Fluid Flow, Heat and Mass Transfer, FFHMT 2015 - Ottawa, Canada
Duration: 30 Apr 20151 May 2017

Other

Other2nd International Conference on Fluid Flow, Heat and Mass Transfer, FFHMT 2015
CountryCanada
CityOttawa
Period30/4/151/5/17

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Keywords

  • Annular flow regime
  • Flow boiling
  • Liquid film
  • Micro-channels
  • Separated flow model
  • Two-phase heat transfer coefficient
  • Uniform heat flux

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

Cite this

Younes, A., Kadem, L., & Hassan, I. (2015). Prediction of heat transfer coefficient in annular flow regime for flow boiling in a horizontal micro tube at a uniform heat flux. In 2nd International Conference on Fluid Flow, Heat and Mass Transfer, FFHMT 2015 Avestia Publishing.