Experimental determination of the convection heat transfer coefficient in an eccentric annular duct Articles uri icon

publication date

  • August 2022

start page

  • 1

end page

  • 9

issue

  • 110664

volume

  • 136

International Standard Serial Number (ISSN)

  • 0894-1777

Electronic International Standard Serial Number (EISSN)

  • 1879-2286

abstract

  • The use of bayonet tube heat exchangers and heaters is widespread in many industrial applications and an improvement in the heat transfer coefficient may provide benefits over other technologies. This work presents novel experimental results about the turbulent convection heat transfer coefficient of air in the annular section of a bayonet tube for two different configurations: concentric and eccentric tubes. For both configurations, the convection heat transfer coefficient was obtained at different air flow rates, therefore, at different Reynolds numbers. In the case of the eccentric configuration, the angular position of the inner tube was varied to determine the circumferential distribution of the local convective heat transfer coefficient. An increase of the convection coefficient was observed for both configurations at higher Reynolds numbers. Concerning the angular position with regard the inner tube, the largest local convective heat transfer coefficient was obtained at the angular position where the distance between the inner and outer tubes was maximum, yielding a value 22.3% higher than in the case of a concentric annular section. All these experimental results were used to propose a new correlation for the local convective heat transfer coefficient as a function of the Prandtl and Reynolds numbers, the eccentricity, and the angular position of the inner tube, with a maximum discrepancy between correlation and experimental data below 10%.

subjects

  • Chemistry
  • Industrial Engineering
  • Mechanical Engineering
  • Physics
  • Renewable Energies

keywords

  • bayonet tube; convection coefficient; eccentricity; heating film; nusselt number correlation