Mathematical modeling and heat transfer in nanofluid flow of Newtonian material between two rotating disks

Abstract

Here, we have discussed the irreversibility in MHD hybrid nanofluid flow with Joule heating, viscous dissipation and activation energy between stretchable rotating disks. Where heat generation, Joule heating and dissipation effects are used to model heat equation while activation energy is used mass equation just to start a chemical reaction. Here, $${\text{GO}}$$ (graphene oxide) and $${\text{TiO}}_{2}$$ (titanium dioxide) with water are used as nanofluids. Contrast of thermophysical properties of these two nanoparticles is very useful because there is huge difference between their thermal conductivities and density. It is very useful to study the velocity, temperature, concentration, entropy generation, Bejan number, skin friction and Nusselt number in contrast of these two nanoparticles. Total entropy rate by thermodynamics second law is computed. Physical features of entropy rate in nanofluids with activation energy are accounted. Nonlinear PDEs are changed to ODEs through transformations. The formulated nonlinear systems are computed through ND-solve method. Influence of several interesting parameters on velocity filed entropy rate, Bejan number, concentration and temperature is graphically discussed for $${\text{TiO}}_{2}$$ and $${\text{GO}}$$ . Velocity and temperature gradients are computed against flow variables. Larger Brinkman number improves the entropy rate. Higher diffusion variables augment both Bejan number and entropy rate.