NUMERICAL AND EXPERIMENTAL-STUDY OF MASS AND MOMENTUM-TRANSFER IN DEVELOPING LAMINAR-FLOW IN ANNULUS

The hydrodynamic characteristics and the mass transfer were determined in the entrance region of an annulus with simultaneous development of velocity and concentration fields. A finite difference method was car ried out to solve the problem by using the boundary layer assumptions. Two kinds of boundary conditions at the entrance were considered: uni form axial velocity and axial velocity at the exit of a porous media, which corresponds to experimental conditions. The velocity profiles at different axial locations were determined by laser Doppler velocimetr y for different values of the Reynolds number. The wall shear stresses and the local mass transfer coefficients were obtained on microelectr odes by performing a polarographic method. The numerical predictions a re in a good agreement with the experimental data.