A Comparison of Circular Duct and Real Hexagonal Duct Results Using Hydraulic Diameter

Yilmaz U. B., Turgut O.

Journal of Polytechnic, cilt.24, sa.4, ss.1593-1604, 2021 (ESCI) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 24 Sayı: 4
  • Basım Tarihi: 2021
  • Doi Numarası: 10.2339/politeknik.768211
  • Dergi Adı: Journal of Polytechnic
  • Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), TR DİZİN (ULAKBİM)
  • Sayfa Sayıları: ss.1593-1604
  • Anahtar Kelimeler: Hexagonal duct, heat transfer, turbulent flow, numerical analysis, HEAT-TRANSFER COEFFICIENT, FORCED-CONVECTION, LAMINAR-FLOW, ENTROPY GENERATION, ENTRANCE REGION, FRICTION FACTOR, TURBULENT-FLOW, SQUARE, TEMPERATURE
  • Gazi Üniversitesi Adresli: Evet

Özet

To see whether the turbulent flow correlations derived for circular ducts can be used for hexagonal cross-sectional ducts using hydraulic diameter, turbulent flow in hexagonal ducts is numerically investigated under constant wall temperature boundary condition using ANSYS Fluent 17.0 software. Investigated parameters are the Reynolds number between 10x10(3)<= Re <= 50x10(3) and side angle of the duct varying between 30 degrees and 90 degrees. Standard k-epsilon model is used as turbulence model. General expressions are proposed for fully developed dimensionless heat transfer coefficient Nusselt number and fully developed Darcy friction factor in terms of Reynolds number and side angle for hexagonal-shaped cross-sectional duct. Results show that side angle of hexagonal duct affects the pressure drop along duct and heat transfer coefficient in duct. Results point out that regular hexagonal duct, theta=60 degrees, gives minimum pressure drop and maximum Nusselt number. It is concluded that correlations given in the literature for circular ducts in turbulent flow can give 14% higher dimensionless heat transfer coefficient, Nusselt number, than that of actual hexagonal duct flow.