Effect of magnetic field on forced convection heat transfer of a non-Newtonian nanofluid through an annulus: an experimental study

In the present study, the steady laminar forced convection heat transfer of a non-Newtonian nanofluid through the annular tube under constant magnetic field and constant heat flux were experimentally investigated. Carboxymethyl cellulose (CMC) and water with 0.2 wt% were used as a base fluid. Copper oxide nanoparticles with 0.25%, 0.5% and 1% volume fractions were used. The variation of local heat transfer coefficient along the annular tube was studied. The mean heat transfer coefficient was obtained at the presence/absence of a constant external magnetic field for different Peclet numbers. Based on the results, the heat transfer coefficient augmented as the volume fraction of nanoparticles was increased. Also it was found that, the presence of the constant magnetic field caused a maximum of 13% enhancement in the mean heat transfer coefficient for the nanofluid with 1% volume fraction compared to the same condition without the magnetic field.