The influences of the geometrical parameters of interrupted annular groove
fin (IAGF) mainly including the annular groove diameter, the groove arc
length, and the fin spacing, on the fin side thermal-hydraulic
characteristics of a finned circular tube exchanger were numerically
investigated by actualizing the custom FORTRAN programing with SIMPLE
algorithm in a nonorthogonal curvilinear coordinate system, and the
regression formulas of average Nusselt number and friction factor with flow
parameters and geometrical parameters were obtained. Compared with the
referential plain fin, IAGF could significantly improve thermal performance
under the same pumping power constraint, and Nusselt number is closely
germane to the secondary flow, which implies that the fin side heat transfer
is depended entirely on the secondary flow strength. For Nusselt number, the
annular groove diameter and the groove arc length have positive effect,
while the fin pitch, the groove circumferential and radial locations have
negative effect. The dominant parameters influencing on friction factor in
turn are the fin pitch, the groove radial location, and the annular groove
diameter. The optimal annular groove diameter is screened, and found that
the optimal annular groove diameter is closely related with Reynolds number
under the same pumping power constraint, while under the same mass flow rate
constraint that is scarcely related with Reynolds number.