An improved low Reynolds number k -? model for heat transfer calculations

Abstract

The paper presents numerical calculations of turbulent exchange of momentum and heat in the flow of air and water respectively at the inlet region of a circular pipe. The calculations are based on the low Reynolds number k-ɛ turbulence model, taking into account the changes of the turbulent Prandtl number Prt across the pipe. Basing on results of experimental work available in the literature, three variants of changes of the Prandtl number Prt were developed. The obtained results of numerical calculations were compared with corresponding results of experimental work and other analytical ones available in the literature. The comparative analysis of the numerical results and other, both experimental and theoretical ones, evidenced a high degree of their conformity, especially in the case of calculations based on case I or III of the change pattern of the Prt number.