Numerical investigation of thermocapillary and buoyancy driven convection of nanofluids in a floating zone

In this paper, the results of adding nanoparticles (spherical shape Al2O3 with a diameter of 20 nm) to silicone oil (Prf=16.08) as a base fluid in a floating zone with aspect ratio equal to unity have been reported. In the absence of gravity the thermocapillary convection, driven by surface tension gradient, is dominant in the floating zone. In the range of Marangoni number considered here, the flow is steady and axisymmetric. Numerical study was conducted on the effect of the increase in the volume fraction of nanoparticles on various thermo–hydrodynamic parameters of the flow, with the use of two phase mixture model and control volume technique. It has been concluded that adding nanoparticles and increasing their volume fraction deteriorate thermocapillary convective characteristics. The effect of gravity (by taking the buoyancy driven convection into account) has also been studied.