Numerical Investigation of Developing Laminar Convection in Vertical Double-Passage Annuli

Abstract

This work numerically explored the developing laminar natural convection in the vertical double-passage cylindrical annuli. The double-passage annuli are designed from three upright coaxial cylindrical tubes with the intermediate cylinder treated as a thin and conductive baffle. In the present study, two thermal conditions are imposed, namely, interior or exterior cylindrical wall is constantly heated, whereas the opposite wall is thoroughly insulated. Using the boundary layer approximation, the nonlinear and coupled governing partial differential equations are numerically solved by employing an implicit finite difference technique. The flow and thermal distributions, heat transfer rates are portrayed for various axial locations, Grashof number and baffle position. The results reveal that the velocity and temperature profiles significantly altered with Grashof number and axial locations. Further, the baffle location plays a major role in controlling the heat transfer in the annular passages.