Annular sector ducts

An annular sector duct is displayed in the inset of Fig. 5.56. Shah and London [1] have calculated the / Re value to a high degree of accuracy using the analytical solution proposed by Sparrow et al. [285]. The results of/Re are presented in Fig. 5.56. 

FIGURE 5.56 Fully developed friction factor for laminar flow in an annular sector duct [1]. 

Ben-Ali et al. [281] and Soliman [286] have investigated fully developed flow and heat transfer in annular sector ducts with the , , and boundary conditions. The Nusselt numbers obtained by those investigators can be found in Table 5.61. 

Simultaneously developing flow in annular sector ducts for air (Pr = 0.7) has been analyzed by Renzoni and Prakash [287]. In their analysis, the outer curved wall is treated as adiabatic, and the boundary condition is imposed on the inner curved wall as well as on the two straight walls of the sector. The fully developed friction factors, incremental pressure drop numbers, hydrodynamic entrance lengths, and thermal entrance lengths are presented in Table 5.62. The term L y used in Table 5.62 is defined as the dimensionless axial distance at which /app Re = 1.05/ Re. The fully developed Nusselt numbers are represented by Nu/< in order not to confuse the reader since the thermal boundary condition applied in Renzoni and Prakash [287] is different from those defined in the section. 

TABLE 5.61 Fully Developed Nusselt Numbers for Annular Sector Duct [281, 286]... 

TABLE 5.62 Fully Developed Fluid Flow and Heat Transfer Characteristics of Annular Sector Ducts with Adiabatic OuterCurved Wall [287]... 

H. M. Soliman, Laminar Heat Transfer in Annular Sector Ducts, J. Heat Transfer, (109) 247-249, 1987. 

---