Homogeneous-heterogeneous reactions in flow of nanofluids near the stagnation region of a plane surface: The Buongiorno's model

The homogeneous-heterogeneous reactions for nanofluids flow are developed incorporating the Buongiorno's nanofluid model, in which the heterogeneous reactions given by isothermal cubic autocatalytic kinetics are assumed to take place on the wall surface, while the homogeneous reactions governed by first order kinetics occur in the ambient fluid. The classical problem of laminar flow in the stagnation region of a plane surface is illustrated as an example to testify the validity of this model. Multiple solutions of this state system are obtained for various physical parameters by means of hysteresis bifurcations. Results show that the ratio of Brownian and thermophoretic diffusivity plays an important role on the appearance of the bifurcation point of multiple solutions, the less this value is, the slower this bifurcation point appears. In other words, nanofluids are expected to alter the transport mechanisms of homogeneous-heterogeneous reactions and therefore have great potentials in applications of the related fields. (C) 2018 Elsevier Ltd. All rights reserved.