FREE CONVECTIVE MASS-TRANSFER AT DOWN-FACING HORIZONTAL SURFACES WITHFREE OR COLLARED EDGES

Free convective mass transfer at down-facing horizontal surfaces was e xperimentally studied using the electrochemical technique with emphasi s on the influence of the edge condition. It was found that the mass t ransfer rate is significantly lower for collared surfaces which was-ex plained in terms of the different fluid flow conditions at the disc ed ge. The previous literature was critically reviewed and reported corre lations were compared with those found for the present case, which, fo r discs with free edges, was found to be Sh(d) = 2.08Ra(d)(0.178) for Ra-d in the range 7 x 10(3) to 1 x 10(11). (C) 1998 Elsevier Science L td.