General equation for heat transfer for laminar flow in ducts of arbitrary cross-sections

Abstract This paper presents the general equations for heat transfer calculations for constant wall temperature in laminar developed flow in ducts of arbitrary cross sections. The results obtained from these equations compare well with the theoretically-calculated values available in the literature for circular, rectangular, triangular, elliptical and parallel plate ducts. The maximum and minimum deviations by these comparisons are −8.7 and +8.0% respectively.