## THERMAL SCIENCE

International Scientific Journal

### RADIATION AND HEAT GENERATION EFFECTS IN MHD MIXED CONVECTION FLOW OF NANOFLUIDS

**ABSTRACT**

Radiation and heat generation effects in unsteady magnetohydrodynamic (MHD) mixed convection flow of nanofluids along a vertical channel are investigated. Silver ()Ag nanoparticles of spherical shapes and of different sizes in water as a convectional 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 nanoparticles, Koo and Kleinstreuer model is used. The problem is modelled in terms of partial differential equations with physical boundary conditions. Analytical solutions are obtained for velocity and temperature, plotted and discussed. It is concluded that increasing the size of Ag nanoparticles (up to specific size (30 nm ) results in a very small velocity increment while for large particle size (30 nm -100nm ), no change in velocity is observed. As the small size of nanoparticles has the highest thermal conductivity and viscosity. This change in velocity with size of nanoparticles is found only in water-based nano fluids with low volume fraction 0.01 while at low volume concentration, no change is observed.

**KEYWORDS**

PAPER SUBMITTED: 2015-07-30

PAPER REVISED: 2016-01-15

PAPER ACCEPTED: 2016-02-26

PUBLISHED ONLINE: 2016-03-12

**THERMAL SCIENCE** YEAR

**2018**, VOLUME

**22**, ISSUE

**1**, PAGES [51 - 62]

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