Mixed Convective Couette Flow of Reactive Nanofluids Between Concentric Vertical Cylindrical Pipes

This paper investigates the effect of buoyancy force on mixed convective Couette flow of a reactive viscous incompressible nanofluid between two concentric cylindrical pipes under bimolecular, Arrhenius and sensitised reaction rates. It is assumed that the inner pipe moves in the axial direction with a uniform velocity while the outer pipe remains fixed and subjected to a convective cooling. The governing equations are obtained and solved numerically using a shooting method coupled with Runge-Kutta-Fehlberg scheme. Three different types of water based nanofluids containing copper, aluminum oxide and titanium dioxide are considered. The effects of pertinent parameters on the fluid velocity, temperature, the shear stress and the rate of heat transfer at the surface of pipes and thermal stability criterion are presented graphically and discussed in detail. Results reveal that the reactive nanofluid velocity within the annulus can be controlled by suitably regulating the ratio of the outer pipe radius to that of the inner pipe radius.