The enhancement of intraparticle mass transport by intraparticle forced convective flow has been recognized in numerous past studies when ''large-pore'' materials are used in the presence of large pressure drops. However, the enhancement of film mass transfer by forced convective flow perpendicular to the ''heterogeneous'' surface has not been previously studied. In this study, a ''unit cell'' model is used which describes the steady-state mass transfer in the concentration boundary layer for the case where forced convective flows parallel and perpendicular to a heterogeneous surface are present. The perpendicular flow field in the momentum boundary layer is determined using the Navier-Stokes and continuity equations. The mass balance equations are solved by the method of collocation on finite elements. The minimum enhancement of film mass transport to the heterogeneous surface, measured by the Sherwood number ([Sh] = k/k*) due to the forced convective flow perpendicular to the surface, given by the Peclet number, Pe(y), is assessed. When Pe(y) < 0.5, [Sh] is nearly independent of Pe(y), and when Pe(y) is larger than 5, [Sh] almost-equal-to Pe(y)/2, i.e., k almost-equal-to upsilon(o)/2, so that D = upsilon(o)delta/2.
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