Exact analysis of miscible dispersion of solute with interphase mass transfer in a poorly conducting couple stress fluid flowing through a rectangular channel bounded by porous layers is considered because of its application in many practical situations. The generalized dispersion model of Sankarasubramanian and Gill is used, which brings into focus the exchange coefficient, the convective coefficient and the dispersion coefficient. The exchange coefficient comes into picture due to the interphase mass transfer and independent of solvent fluid viscosity. It is observed that the convective coefficient increases with an increase in the porous parameter while it decreases with an increase in the couple stress parameter. The dispersion coefficient is plotted against wall reaction parameter for different values of porous parameter and couple stress parameter. It is noted that the dispersion coefficient decreases with an increase in the value of couple stress parameter but increases with porous parameter.

We investigate in this paper the simultaneous effects of electric field, couple stress, porous parameter and slip at the permeable surface on the generalized dispersion of an unsteady convective diffusion in a poorly conducting fluid in a channel bounded by porous layers. A two dimensional flow has been considered and the resulting partial differential equations have been solved analytically. The solutions are computed and the results show that the solute is dispersed relative to a plane moving with the mean speed of couple stress poorly conducting fluid with a relative unsteady dispersion coefficient. These relative unsteady dispersion coefficients are numerically computed and found that they increase with the increase in porous parameter and decrease with an increase in couple stress parameters. We have also estimated the contribution of diffusion and pure convection on the generalized dispersion coefficient. The effect of pure convection, neglecting diffusion terms on mean concentration is computed and the results show that the effect of pure convection decreases mean concentration compared to combined effect of convection and diffusion.