Numerical analysis for heat transfer characteristics of an oblique discrete rib mounted in a square duct

Three-dimensional numerical simulation was conducted by making use of a Reynolds Average Navier-Stokes (RANS) approach for the flow in a duct accompanying longitudinal vortices, and discussions are given for the related thermal fields. In the first half of this article, applicability of the turbulence models adopted in the present study is discussed based on the comparison with some published experimental results. The main part of the article treats the numerical results for the flow around a discrete rib attached obliquely to the flow direction onto the bottom wall of a square duct in which a fully developed turbulent flow is established at the inlet. Due to the rib inclination and the gaps existing between the rib ends and the side walls, noticeable heat transfer augmentation is obtained downstream of the rib, produced by a strong secondary flow motion.