Effect of nanoparticles on natural convection in fluids

Abstract

The paper investigates the impact of nanoparticles on the onset of convection currents in a fluid layer under small temperature gradient. The partial differential equations derived from conservation laws of mass, momentum, nanoparticles and energy are considered which include the nano effects (Brownian motion and thermophoresis). Nanoparticle volume fraction is considered to be small in the fluid and hence initial solution of equations assumes it to be constant while temperature and pressure vary in vertical direction. Small perturbations are added to steady state solution and the obtained partial differential equations are converted into ordinary by seeking solution which is exponential in time and periodic in space. To get the complete insight of the problem, variables are not combined or replaced by new ones at any stage leading to more significant expressions. Further, the equations are solved to get thermal Rayleigh number which establishes the influence of physical properties and diffusion effects of nanoparticles on the onset of convection cells. A detailed analysis of the problem is done numerically which lead to significant results and hence affect the convective nature of the system broadly. Copper in spite of having higher conductivity has lesser impact on stability than aluminium because of its higher density.