Comparative analysis of Yamada-Ota and Xue models for hybrid nanofluid flow amid two concentric spinning disks with variable thermophysical characteristics

The surprising features of carbon nanotubes such as featherweight, mechanical permanence, outstanding electrical and thermal conductivities, and physicochemical aptness make them impeccable material for electrochemical contraptions. Having such astounding physiognomies in mind our purpose in this study is to make a comparison of the performance of Yamada-Ota and Xue models for a nanofluid flow amidst two rotating disks in a spongy medium. The majority of nanofluid flow models in the available literature considered constant thermal conductivity and viscosity. Nevertheless, here the whole scenario is deliberated with variable characteristics. The novelty of the envisaged mathematical model is enriched considering the chemical species of both types amalgamated with the entropy generation minimization analysis keeping in view the liquid and gaseous states. The numerical solution of the governing system is obtained by using the bvp4c function of the MATLAB software. The graphical outcomes of arising parameters solid nanoparticles volume fraction (0.005≤φ2≤0.06), variable viscosity (−5≤θr≤2.5), thermal conductivity (1.0≤ε≤2.0), surface catalyzed parameter (0.0≤Kvs≤0.3), homogeneous reaction parameter (0.3≤Kc≤0.7), heterogeneous reaction parameter (0.3≤Ks≤0.7), Brinkman number (0.2≤Br≤0.6), and temperature difference parameter (0.5≤α1≤1.2), versus associated profiles are analyzed logically. It is examined that for positive values of variable viscosity parameter (gases) the axial velocity declines, nevertheless, an increase in velocity distribution is seen for negative values of variable viscosity parameter (liquids).