Numerical investigation toward improving heat-transfer predictions in a turbulent channel flow

In developing flow between two parallel plates, even if available models and near-wall treatments provide adequate mean flow velocities, they fail to predict suitable turbulent kinetic energy profiles near walls. Turbulent kinetic energy is involved in determination of eddy viscosity which could provide inaccurate temperature profiles. In order to improve the turbulent kinetic energy a defined function based on an analytical profile is developed and implemented in Fluent. A Reynolds averaged two equation Shear Stress Transport k–ω model and three different low-Reynolds-number models namely models of Lam and Bremhorst, Yang and Shih and Chang et al., are considered. Mean streamwise velocity, temperature and kinetic energy profiles are compared to direct numerical simulation data for friction Reynolds number Reτ = 150. Simulation results show more accurate profiles.

► A user defined function was calibrated, developed and implemented in Fluent. ► Mean streamwise velocity, temperature and kinetic energy profiles were improved. ► The average Nusselt number is improved by the various turbulence models. ► The low-Reynolds-number k–ɛ model of Yang and Shih shows excellent agreement. ► Accurate near-wall turbulence modeling greatly influences wall heat-transfer rates.