Turbulent heat transfer and fluid flow in a porous-baffled channel

Experiments were conducted to examine the effect of porous-type baffles on heat transfer and friction in a baffled channel, The porous-type baffles are arranged on the bottom and top channel walls in a staggered manner. Flowfield, pressure toss, isotherm pattern, and channel centerline heat transfer coefficients are obtained inside the periodic cell formed between the segmented baffles. Results of the conventional solid-type-baffled channel are also obtained for comparison, The void fraction upsilon(0), of porous-type baffle and the baffle spacing S/H are fixed at 0.42, and 1.0, respectively; whereas the baffle height ratio h/H varies from 0.25 to 0.75 and the flow Reynolds number Re ranges from 1 x 10(4) to 5 x 10(4), respectively, It is disclosed that the now patterns around the porous- and solid-type baffles are entirely different, These different transport phenomena, in conjunction with the change in baffle effectiveness significantly influence the Local heat transfer coefficient distributions but negligibly influence the average heat transfer coefficients. Relative to the solid-type-baffled channel, the porous-type-baffled channel has a lower friction loss, Consequently, the porous-type-baffled channel yields a better thermal performance under constant pumping power. Compact correlations for the average Nusselt number and friction factor are also developed in terms of how and baffled parameters.