The paper investigated forced convective fluid flow and heat transfer in gravitationally oriented circular ducts with
equi-spaced internal longitudinal fins for the purpose of augmenting heat transfer in heat exchangers of circular
cross-section. Navier–Stokes equation of motion and energy transport equation were adopted as the governing
equations for the fluid flowing in the geometry. The governing equations were non-dimensionalized using certain
defined transformation parameters. A computational algorithm was developed based on the finite difference scheme
for the normalized governing equations. A Quick-BASIC program was developed for the implementation of the
scheme. The computed results show that between 00-150 pipe inclinations, there is a rapid increase in heat transfer
enhancement which slowly increases towards 750 inclination and remains almost a plateau up to the vertical position
of the pipe. It was discovered that although increased fin height above H = 0.2 increases the heat transfer surface
area: parameters of fluid volume and flow velocity are adversely affected and therefore, any protrusion beyond H =
0.2 is a waste of material and resources. Reduction of fin half angle positively affects the heat augmentation. For an
inclination range of 0o ?? ? 8o , increase in the number of fins increases the mean Nusselt number. The effect of
ratio of conductivity of solid to fluid on heat transfer was found to be significant only for high Prandtl number fluid
flow. This investigation does not only provide consistent results with those previously computed via fluid flow and
heat transfer in circular ducts with longitudinal internal fins but also emphasize critically the influence of pipe
orientation on heat transfer particularly for piping network.