Convective heat transfer in ribbed square channels

Three-dimensional laminar forced convective heat transfer in ribbed square channels is investigated In these channels, transverse and angled fibs are placed on one or two of the walls to form a repetitive geometry. After a short distance from the entrance, also the flow and the dimensionless thermal fields repeat themselves from module to module allowing the assumption of periodic, or anti-periodic, conditions at the inlet/outlet sections of the calculation cell. Prescribed temperature boundary conditions are assumed at ad solid walls, including the ribs. Pressure drop and heat transfer characteristics are compared for rib angles ranging from 90degrees (transverse ribs) to 45degrees, and different values of the Reynolds number. The influence of rib geometries is investigated below and above the onset of the self-sustained flow oscillations that precede the transition to turbulence. Numerical simulations are carried out employing an equal order finite-element procedure based on a projection algorithm.