  To fully evaluate a turbulent flow, Direct Numerical Simulation (DNS) is the
most accurate method by far and requires considerable computational power and
time; not optimum for industry standards. Developing an alternative model,
providing results with reasonable accuracy would resolve this issue. Reynolds
Averaged Navier Stokes (RANS) modeling has proven its worth in addressing this
phenomenon. In this study, we investigated the RANS turbulence models from
COMSOL for fully developed single-phase flow in a two-dimensional axisymmetric
pipe domain with constant heating at the wall and periodic boundary conditions
at the inlet and outlet. Heat transfer in the fluid module has been added to
address the heat transfer phenomenon. We evaluated the computed results with
existing DNS data to match the accuracy of the RANS models. RANS simulations
are conducted for friction Reynolds number, i.e., Re_{\tau}= 180, 314, and 395
with varying Prandtl numbers, i.e., Pr = 0.71, 2, 5, and 7. Multiscaling
analyses in the flow's inner, outer, and meso scaling regions are performed for
fluid and heat transfer profiles, i.e., mean streamwise velocity, Reynolds
shear stress, mean streamwise temperature, and turbulent heat flux, to compare
with the DNS data. The investigation reports the scaling analysis's
effectiveness and shows that RANS turbulence models can be used to describe
such flow with reasonable accuracy.
