Diffusion Of Chemically Reactive Species Of An electrically Conducting Visco-elastic Fluid Immersed In a Porous Medium Over A Stretching Sheet With Prescribed surface Concentration And Prescribed Wall Mass Flux

摘要

In this paper, we present a mathematical analysis of mass transfer phenomena in a magneto hydrodynamic visco-elastic fluid immersed in a porous medium with prescribed surface concentration and prescribed wall mass flux. The influence of reaction rate on the transfer of chemically reactive species is studied. The flow is caused solely by the linearly stretching sheet and the reactive species is emitted from this sheet and undergoes an isothermal and homogeneous one stage reaction as it diffuses into the surrounding fluid. Several non-dimensional similarity transformations are introduced to reduce the concentration conservation equation to an ordinary differential equation in both the cases. (PST and PHF). An exact analytical solution due to Siddappa and Abel (ZAMP 36, 1985) is adopted for velocity, whereas the concentration equation is solved analytically for first order reactions in both the PST and PHF cases. The computations showed that the effect of destructive chemical reaction is to reduce the thickness of the concentration boundary layer and increase the mass transfer rate from the sheet to the surrounding fluid in the presence of a transverse magnetic field. This effect is more effective for zero and first order reactions than for thesecond and higher order. The effect of various physical parameters are analysed in the PST and PHF cases. The effects of all these parameters on wall concentration gradient are also discussed.