Radiation and heat generation effects in magnetohydrodynamic mixed convection flow of nanofluids

Abstract

Radiation and heat generation effects in unsteady magnetohydrodynamic mixed convection flow of nanofluids along a vertical channel are investigated. Silver nanoparticles of spherical shapes and of different sizes in water as a convection-al base fluid are incorporated. The purpose of this study is to measure the effect of different sizes of nanoparticles on velocity and temperature. Keeping in mind the size, particle material, shape, clustering and Brownian motion of nanoparti-cles, Koo and Kleinstreuer model is used. The problem is modeled in terms of partial differential equations with physical boundary conditions. Analytical solu-tions are obtained for velocity and temperature, plotted and discussed. It is con-cluded that increasing the size of Ag nanoparticles (up to specific size, 30 nm, re-sults in a very small velocity increment while for large particle size (30-100 nm), no change in velocity is observed. As the small size of nanoparticles has the high-est thermal conductivity and viscosity. This change in velocity with size of nano-particles is found only in water-based nanofluids with low volume fraction 0.01 while at low volume concentration, no change is observed.