PipeFlow_Laminar
Procedure PipeFlow_laminar (Re, Pr, LoverD: Nusselt_T, Nusselt_H, f) returns the average Nusselt number and friction factor for a circular tube characterized by Reynolds and Prandtl numbers, length/diameter, and relative roughness. The Reynold's number is expected to be < 2300.
Inputs:
Re - Reynolds number based on properties evaluated at the bulk average temperature [-]
Pr - Prandtl number of the fluid evaluated at the bulk average temperature [-]
LoverD - ratio of tube length to diameter.
Outputs:
Nusselt_T - average Nusselt number assuming a constant wall temperature
Nusselt_H - average Nusselt number assuming a constant wall heat flux
f - apparent Darcy friction factor [-]
Notes
The Darcy friction factor is calculated using a correlation recommended in Eqn 192, p98 of Shah and London (1978). The correlation is applicable in the developing and fully-developed region and limits to 64/Re.
The average Nusselt number correlations were fit to data provided in Tables 20 and 22 of Shah and London (1978) based on data from Hornbeck (1965). Table 22 Shah and London provides only the local Nusselt number. The local values were integrated to obtained average values which were used to establish the correlation as reported in Section 5.2.4 of Nellis and Klein. The average Nusselt numbers assume simultaneously developing flow; however, it is possible to obtain values consistent with thermally developing/hydrodynamically developed flow by calling the procedure with a large Prandtl number.