DIFFUSION OF A CHEMICALLY REACTIVE SPECIES FROM A STRETCHING SHEET

The transfer of chemically reactive species in the laminar flow over a n elastic plane surface is considered. The viscous flow is driven sole ly by the linearly stretched surface and the reactive species is emitt ed from this sheet and undergoes an isothermal and homogeneous one-sta ge reaction as it diffuses into the surrounding fluid. A similarity tr ansformation is devised, which reduces the concentration conservation equation to an ordinary differential equation. An exact analytical sol ution due to Crane [Z. Angew. Math. Phys. 21, 645-647 (1970)] is adopt ed for the velocity, whereas the concentration field is obtained numer ically. The computations showed that the principal effect of a destruc tive chemical reaction is to reduce the thickness of the concentration boundary layer and to increase the mass transfer rate from the stretc hing sheet to the surrounding fluid. This effect appeared to be more p ronounced for a first-order reaction than for second- and third-order reactions. A nonuniqueness of the concentration distributions for gene rative first-order reactions was revealed by the computations.