Heat and mass transfer characteristics of Al 2 O 3 /H 2 O and (Al 2 O 3 +Ag)/H 2 O nanofluids adjacent to a solid sphere: A theoretical study

A theoretical study is carried out to explore the heat and mass transfer features in the flow of two types nanofluid, i.e., Al2O3/H2O micropolar nanofluid and (Al2O3+Ag)/H2O hybrid nanofluid, adjacent to a solid sphere. Furthermore, simultaneous effects of linear thermal radiation and chemical reaction are also explored on the heat and mass transfer characteristics. In mathematical formulation basic conservation laws are utilized along with the Soret and Doufer effects as a coupling agents in the energy and mass concentration equations. The normalized variables are used to transform the governing system of non-linear partial differential equations into the system of dimensionless partial differential equations. Stream function reduces the number of dependent variables and the resulting system is solved numerically by Keller box method. Several plots are presented to explore the impact of involved parameters on the different profiles and engineering interest quantities for both types of fluids. The temperature profile and Nusselt number are large in magnitude for hybrid nanofluid as compared to Al2O3/water based nanofluid. The heat transfer and mass transfer rates rises with thermal radiation parameter and chemical reaction parameter, respectively.