Effects of flow fluctuations and buoyancy on heat transfer from a sphere in non-Newtonian nano fluids: Potential for intensification

•Shear-thinning viscosity augments heat transfer significantly.•This effect is accentuated under pulsating flow conditions.•Imposed aiding-buoyancy flow suppresses flow separation.•Rate of heat transfer can be enhanced by up to 35% with pulsations in laminar flow itself.