Natural convection of power-law fluid between two-square eccentric duct annuli

► The paper investigated natural convection of a non-Newtonian power-law fluid between two eccentric duct annuli. ► Equations are solved numerically based on second order upwind and SIMPLE algorithm. ► Intensity of buoyancy effects increases when Rayleigh number increases for n < 1 (pseudoplastic fluid) and n > 1 (dilatant fluid). ► Varying the Prandtl number almost does not affect heat and fluid patterns between two cylinders.