Free convection heat transfer from vertical and horizontal short plates

Abstract

Free convection heat transfer from vertical and horizontal short plates was numerically analyzed by the finite-difference method. The present results regarding average Nusselt number on vertical and horizontal thin plates can be closely approximated by the following equation: Vertical thin plate, Nul = 0.448 + 0.46Grl 1 4 , Pr = 0.72 and 15 ⩽ Grl ⩽ 27,000. Horizontal thin plate, Nuld = 0.353 + 0.509Grd 1 5 , Pr = 0.72 and 4 ⩽ Grd ⩽ 27,000. These relations between Nusselt and Grashof numbers show the same tendency as the experimental results and give slightly lower Nusselt numbers. The average Nusselt numbers on the vertical plate ( height = l) with finite thickness (d) can be approximated by the above correlation for a thin vertical plate with an error within about 6% using characteristic length l + d in both Nusselt and Grashof numbers instead of l, in the range of L ⩾ 5 and D ⩽ 10. Where L is dimensionless plate height and D is dimensionless plate thickness.