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Abstract : |
The mass-transfer coefficients have been obtained experimentally for natural convection from vertical wavy surfaces of varying amplitude-to-wavelength ratio (a/lambda) when embedded in saturated porous media. The porous media were formed by randomly packing glass spheres of 3-, 4-, and 6-mm diameters. A limiting diffusion current technique based on cathodic reduction of cupric ions in acidic solution was used. The obtained data correspond to high Rayleigh numbers and exhibit non-Darcian effects. The mass-transfer coefficients from the wavy surfaces in porous media can be estimated as Sh(L)(*) = [3.3284 - 2.4068(a/lambda)](Ra-L(*)/Da(L))(0.26) in the studied range of Ra-L(*)[(1.31 x 10(6)) - (5.56 x 10(7))], where Ra-L* and Da(L) are the modified Rayleigh and Darcy numbers, respectively., |
