Forced Turbulent Convection Along Heated and Cooled Walls With Variable Fluid Properties

Lorenzo Sufra*, Helfried Steiner

*Korrespondierende/r Autor/-in für diese Arbeit

Publikation: Beitrag in einer FachzeitschriftArtikelBegutachtung

Abstract

The effect of temperature depending material properties on heat and momentum transfer along heated/cooled walls in turbulent pipe flow was investigated using direct numerical simulations (DNS). For the considered thermal wall conditions, always associated with a molecular Prandtl number well over unity Prw = 10, the significantly dampened/enhanced turbulent motion caused by the increase/decrease of the viscosity with distance to the heated/cooled wall turned out to clearly dominate over the opposite trend of the enthalpy fluctuations. The Nusselt number and, quantitatively less pronounced, the wall friction coefficient are accordingly decreased/increased for the heated/cooled case. A comparison against a well-established Nu-correlation unveils the limits of the generally applied approach, which is essentially based on uniform bulk flow conditions and subsequently modified accounting for material property variation, when applied to heated and cooled conditions. An enhanced disparity of the turbulent normal stresses is observed inside the inertial subrange for the heated case, indicating a stronger deviation from isotropic turbulence, which possibly challenges mostly isotropic standard turbulence models
Originalspracheenglisch
Aufsatznummer011401
Seitenumfang10
FachzeitschriftJournal of Fluids Engineering
Jahrgang144
Ausgabenummer1
DOIs
PublikationsstatusVeröffentlicht - Jan. 2022

Schlagwörter

  • forced convective heat transfer
  • material property variation
  • turbulence near heated/cooled walls

Fields of Expertise

  • Mobility & Production

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