Conference Dates

June 22-27, 2014


The effect of temperature dependent viscosity on natural convective boundary-layer flow of a nano-fluid over an isothermal horizontal plate is investigated numerically. The viscosity of the fluid is assumed to have an exponentially decaying dependence on temperature ν=ν0e−b(T−T∞). A similarity analysis is presented for field equations embodying conservation of total mass, momentum, thermal energy and nano-particles. The analysis shows that velocity, temperature and nano-particle volume fraction profiles in the respective boundary layers depend on the viscosity parameter γ besides the pertinent parameters such as buoyancy ratio Nr, Brownian motion Nb, thermophoresis Nt and Lewis number Le. From physical considerations one expects that an increase in the viscosity must result in lower heat transfer rates. Results in accordance with the physical considerations are obtained in this study. The study also investigates the effect of the presence of an internal heat source in the porous medium by considering the internal heat generation term in the energy equation. In the presence of the heat source the heat transfer rate is lower whereas the nanoparticle volume fraction rate is higher than those obtained in the absence of the source term.