The Reynolds-averaged computation of turbulent flow with
heat transfer most commonly introduces the turbulent Prandtl
number to relate the turbulent fluxes of momentum and heat.
Its significant deviation from a uniform bulk flow value for high
molecular Prandtl numbers requires a reliable description of this
parameter for predicting accurately the heat transfer. The present
study proposes a model for the near-wall variation of this important
quantity for use in an analytically computed solution of
heated turbulent pipe flow. The comparison of the predictions
against results from Direct Numerical Simulation (DNS) and experiments
proves the proposed analytical approach as a computationally
efficient alternative to the much costlier numerical approach
with still acceptable accuracy. The analytically obtained
results do not only demonstrate the reliability of the proposed
model for the near-wall behavior of the turbulent Prandtl number,
but also highlight the significance of the dependence of the
material properties on the temperature. Numerical simulations
mostly neglect this effect to avoid a further increase of the already
high computational costs associated with the discretized
solution of the heated/cooled flow field.
Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .