NATURAL-CONVECTION IN A HORIZONTAL POROUS ANNULUS WITH MIXED TYPE OF RADIAL BAFFLES

The feasibility of using different combinations of inner and outer par tial baffles to improve the effectiveness of pipe insulation is numeri cally investigated in this paper. Calculations have covered a range of Rayleigh numbers of practical interest, i.e., 50 less-than-or-equal-t o Ra less-than-or-equal-to 500. For each baffle configuration, the rel ation between the heat loss and baffle orientation angle is also caref ully examined. The results confirm the effectiveness of radial baffles in the supression of natural convection which may arise in a pipe ins ulation. Among the three cases studied, inner partial baffles give the best performance.