Ag. Straatman et al., HEAT-TRANSFER ENHANCEMENT FROM A VERTICAL, ISOTHERMAL CHANNEL GENERATED BY THE CHIMNEY EFFECT, Journal of heat transfer, 115(2), 1993, pp. 395-402
A numerical and experimental investigation of free convection from ver
tical, isothermal, parallel-walled channels has been undertaken to exp
lore the heat transfer enhancement obtained by adding adiabatic extens
ions of various sizes and shapes. Investigations were carried out for
air (Pr = 0.7) over a wide range of wall heating conditions. In all ca
ses, the adiabatic extensions were able to increase heat transfer. The
increase varied from 2.5 at low Ra to 1.5 at high Ra*. The experimen
tal and numerical results are in excellent agreement. A single correla
tion accounting for the channel aspect ratio L(h)/b, expansion ratio,
B/b, modified Rayleigh number, Ra and heated length ratio, L(h)/L is
presented.