General equations for fully developed fluid flow and heat transfer characteristics in complex geometries

This paper presents general equations for laminar fully developed friction factor, incremental pressure drop and Nusselt number of Newtonian fluid flo wing in ducts of arbitrary cross sections. These general equations are obta ined using some definitions, e.g. equivalent diameter, number of imaginary circles inside specific geometry and the diameter of surrounded circle. The comparison of the results obtained from these equations with the theoretic ally calculated values available in the literature for various ducts indica tes the accuracy of this investigation. (C) 1999 Elsevier Science Ltd.