Heat-transfer characteristics in annuli with blowing or suction at the walls

Abstract

Numerical solutions were obtained for thermally and hydrodynamically developing laminar flow in annular passages with blowing and suction at the walls. Two separate thermal boundary conditions at the walls were studied: arbitrarily prescribed constant temperatures and constant heat fluxes at each wall. Cases involving blowing, suction, and impermeable walls were considered. Assuming that the properties of the fluid are constant and the injection or extraction velocities at the walls are uniform, the results were obtained in the form of pressure drops and Nusselt numbers. The results are presented for several inner-to-outer tube radius ratios, Prandtl numbers, and injection and extraction Reynolds numbers at the walls. ci,k Cp Dh dj,k = Ej,k — h K k Nu = P+ = P Pr