Heat Transfer Coefficients — Internal Natural Convection
Narrow Chimney, Parallel Plates
Figure 4-24: Schematic representation of geometry and parameters for the heat transfer coefficient correlation applied to natural convection in a parallel-plate narrow chimney.
If RaL < H ⁄ L and T > Text, then
(4-133)
where the plate distance, L, and the chimney height, H, are correlation inputs (equation 7.96 in Ref. 38). RaL is given by Equation 4-126. The material data are evaluated at (T + Text) ⁄ 2.
Narrow Chimney, Circular Tube
Figure 4-25: Schematic representation of geometry and parameters for the heat transfer coefficient correlation applied to natural convection in a circular narrow chimney.
If RaD < H ⁄ D, then
where the tube diameter, D, and the chimney height, H, are correlation inputs (table 7.2 in Ref. 38 with Dh = D). RaD is given by Equation 4-126 with L replaced by D. The material data are evaluated at (T + Text) ⁄ 2.