Forced convection heat transfer in a bundle of 12 rods

The paper describes the heat transfer experiments performed with two bundles of 12 electrically heated rough rods. The fundamentals of the SAGAPO code are given. SAGAPO calculates the friction and heat transfer coefficients in turbulent flow by integrating the logarithmic universal laws of the wall for velocity and temperature in the various coolant channels confined by rough surfaces. The code accounts for turbulent mixing and cross flow among the channels, for spacer effects on wall temperatures and pressure drop, for fin efficiency effects due to the roughness ribs, and for inlet effects on wall temperatures in case of smooth rods. Also laminar flow can be calculated. Comparisons between computed and experimental results on pressure and temperature distributions are presented