A COMPLEMENTARY EXPERIMENTAL AND NUMERICAL STUDY OF THE FLOW AND HEAT-TRANSFER IN OFFSET STRIP-FIN HEAT-EXCHANGERS

A detailed analysis of experimental and numerical results for flow and heat transfer in similar offset strip-fin geometries is presented. Su rface-average heat transfer and pressure drop, local Nusselt numbers a nd skin friction coefficients on the fin surface, instantaneous flow s tructures, and local time-averaged velocity profiles are contrasted fo r a range of Reynolds numbers using both prior and new experimental an d numerical results. This contrast verifies that a two-dimensional uns teady numerical simulation captures the important features of the flow and heat transfer for a range of conditions. However, flow three-dime nsionality appears to become important for Reynolds numbers greater th an about 1300 and thermal boundary conditions are important for Reynol ds numbers below 1000, The results indicate that boundary layer develo pment, flow separation and reattachment, wake formation, and vortex sh edding are all important in this complex geometry.