Heat transport modification by finitely extensible polymers in laminar boundary layer flow

We study how heat transport is affected by finitely extensible polymers in a laminar boundary layer flow within the framework of the Prandtl–Blasius–Pohlhausen theory. The polymers are described by the finitely extensible nonlinear elastic-Peterlin model with a parameter $b^{2}$, which is the ratio of the maximum to the equilibrium value of the trace of the polymer conformation tensor. For very large $b^{2}$, heat transport is reduced. When $b^{2}$ is small, heat transport is enhanced. We investigate the transition from heat reduction to heat enhancement as a function of the polymer relaxation time and concentration, and show that the transition can be explained in terms of the functional shape of the space-dependent effective viscosity due to the polymers.