Quartic autocatalysis on horizontal surfaces with an asymmetric concentration: Water-based ternary-hybrid nanofluid carrying titania, copper, and alumina nanoparticles

Understanding the mechanisms and kinetics of homogeneous (i.e. water-based ternary-hybrid nanofluid) and heterogeneous (i.e. catalyst) reactions is capable of creating a more effective distribution of species and quality of fluids at the outlet. Thus, the present study focuses on analyzing the quartic type homogeneous-heterogeneous reactions in ternary-hybrid nanofluid of copper, alumina, and titania nanoparticles with water at the surface of a stationary/moving flat plate. The leading non-linear partial differential equations were transformed into a set of ordinary differential equations using local similarity transformations. The resultant non-linear ordinary differential equations were numerically solved using MATLAB's built-in BVP4C tool to explore the impact of pertinent factors. From the design side of view, the Tiwari-Das model for nano-liquid was employed to study the flow-thermal behaviour of the nanofluid. The thermal conductivity formulations were taken from experimental works to incorporate the spherical, platelet and cylindrical-shaped nanoparticles. The proposed concept is comparatively analyzed for Blasius and Sakiadis flows. The homogeneous bulk fluid and heterogeneous catalyst concentrations are observed for small and large nanoparticle volume fractions. The investigation shows that the strength of homogeneous and heterogeneous reactions has the opposite effect on the concentration fields. Strong correlations exist between the heterogeneous catalyst's diffusivity and the homogeneous bulk fluid's viscosity. Mass diffusion became more prevalent at the surface as the Schmidt number surged. Conversely, the bulk fluid concentration was highest in areas far from the surface.