Stability analysis of miscible displacement by non-Newtonian nanofluid with different diffusion coefficients

This paper investigates the effect of nanoparticles on the thermo-viscous fingering instability of non-Newtonian fluids during miscible displacements in homogeneous porous media. Nanoparticles are added to the fluid with variable and constant diffusion coefficients, and both the displacing fluid and the displaced fluid are considered as non-Newtonian fluids. The results indicate that the nanoparticles demonstrate efficacy in mitigating the thermo-viscous fingering instability when variable diffusion coefficients are employed, in contrast to scenarios where constant diffusion coefficients are utilized. In contrast to the situation with a constant diffusion coefficient, the shear thinning characteristics and the yield stress properties of the displaced fluid contribute to an increase in instability. Furthermore, the thermal parameters positively influence the rate of Brownian motion exhibited by the nanoparticles.