Thermo-diffusion and non-uniform heat source/sink effects on hydromagnetic flow of Cu and TiO2 water - based nanofluid partially filled with a porous medium

Abstract

The study of nanofluids is important due to its vast public health potential. There exist many biomedical applications for nanofluids including drug delivery, magnetic cell separation, hyperthermia testing, photoablation therapy, biosensor development, bone-substituting implants, bioimaging, cell labeling, and gene delivery. Nanofluids are useful in biomedical analysis and treatment, owing to their properties of chemical stability, non-toxicity, biocompatibility, and high saturation magnetization, and they are useful in optical imaging, imaging of cells and tissues, and sensing of target molecules. Herein, nanofluids are studied for their thermo-diffusion effect on magnetohydrodynamic flow via a porous medium along a stretchable surface with variable wall thickness. The effects of nonuniform heat source/sink, thermal radiation, and first order chemical reactions are considered. Distinctly shaped nanoparticles, namely copper (Cu) and titanium dioxide (TiO2), are utilized, considering water as the base fluid. Copper nanoparticles can be used in bone implantation, fracture healing, radiographic examination, image sensing, and bioimaging such as MRI scans. Titanium dioxide (TiO2) is useful in the preparation of cosmetics and food, as well as in medicine. The set of dimensional governing equations is transformed to dimensionless equations by using suitable similarity variables. The non-linear equation set is solved numerically by using the MATLAB bvp4c package. The impact of pertinent fluid parameters is provided in tabular form and analyzed graphically. From the results, it is evident that the depreciation of fluid velocity and the nanofluid temperature is higher in the Cu-water than the TiO2 -water nanofluid. Moreover, it was observed that the enhancement in the chemical reaction parameter causes an increase in the reaction between nanoparticles. Finally, with the presented results, we conclude that metallic-type nanoparticles play an important role in heat transfer phenomena. Keywords: Variable wall thickness sheet, Magnetohydrodynamics, Porous medium, Copper and titanium oxide nanoparticles, Non-uniform heat source/sink, Thermo-diffusion effect