Revisit gas d c D J=D C-C dynamics. dx d(x Boundary layer Layer thickness, 8(x) 入 And we saw gas dIffuSivity D (unlike solid 2 gas vel: uo boundary layer wafer water X=L Fuld dynamics:6(*=nr p=mass density, n= viscosity puo 6(x)a=2r/ 2 L Reynolds #:Re Puo L 3√ Re ease of gas flc So √Re 2 Mon.. Sept. 15. 2003Revisit gas J1 = hg(Cg - Cs) dC D J1 = D = (Cg - Cs) dynamics: dx d(x) Boundary layer Layer thickness, d(x) lvx And we saw gas diffusivity D = (unlike solid) 2 z u gas vel: u0 boundary layer Cg d (x) d (x) us = 0 Cs wafer wafer x x = L hx Fluid dynamics: d(x) = r = mass density, h = viscosity ru0 L 1 h 2 L Reynolds #: Re = ru0L d = Ú d(x)dx = 23 L ru0L ≡ 3 Re ease of gas flow h L 0 D 3 D Æ Re So: hg = d 2 L Mon., Sept. 15, 2003 6