Abstract
Theoretical and experimental studies were made of the heat transfer at the thermal entrance region in a horizontal triangular duct, to obtain the local and mean Nusselt number of combined free and forced laminar convection for high Prandtl number fluid under the boundary condition of uniform wall temperature.
For a region without free convection effects a solution of Nusselt number based on Leveque''s method was shown for arbitrary triangular ducts. On the other hand, for a region with the free convection effects a numerical solution of Nusselt number using the finite difference method for the triangular coordinate system was proposed for isosceles triangular ducts with apex angles of 30, 60 and 90 degrees.
Furthermore, the influence of the rotation angle around the horizontal axis on Nusselt number was examined and suggested to be relatively small.
The experimental results obtained by the electrochemical method support fairly well the theoretical results.
