As shown in the figure below, liquid A evaporates in the z-direction and passes through a layer of gas B occupying the region between z=0 and z=L. Suppose that the species A undergoes a chemical reaction (-rA = kCA2) where CA is the concentration of species A. Also, suppose that NB = -NA/2 throughout the system where NA and NB are the molar fluxes of species A and B, respectively. Furthermore, the diffusion coefficient (DAB) of species A varies with its mole fraction (xA) as DAB = D0(1-xA2/4) where D0 is a constant. Find the steady-state concentration (or mole fraction) profile of species A as a function of z. Use the boundary condition of xA=xA0 at z = 0 and xA=xAL at z=L. Assume that diffusion occurs only in the z-direction and the total concentration C of the gas mixture is constant.
As shown in the figure below, liquid A evaporates in the z-direction and passes through a layer of gas B occupying the region between z=0 and z=L. Suppose that the species A undergoes a chemical reaction (-rA = kCA2) where CA is the concentration of species A. Also, suppose that NB = -NA/2 throughout the system where NA and NB are the molar fluxes of species A and B, respectively. Furthermore, the diffusion coefficient (DAB) of species A varies with its mole fraction (xA) as DAB = D0(1-xA2/4) where D0 is a constant. Find the steady-state concentration (or mole fraction) profile of species A as a function of z. Use the boundary condition of xA=xA0 at z = 0 and xA=xAL at z=L. Assume that diffusion occurs only in the z-direction and the total concentration C of the gas mixture is constant.
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