Numerical simulation and analysis of natural convective flow and heat transfer of nanofluid under electric field

To study the effect of electric field on the natural convective heat transfer enhancement mechanism of nanofluid, numerical study was carried out by the lattice Boltzmann method (LBM). The physical model and boundary conditions were established based on experiments. The velocity and temperature distributions with various conditions were compared. The electric field forces on nanoparticle were also discussed. Simulation results reveal that electrophoretic force plays the most important role in the motion of the nanoparticle. The simulation values are in good agreement with the experimental results. Moreover, the electric field forces reform the velocity field and temperature field generated by natural convection. The local thermal conductivities of nanofluid are improved by the local electric field. Besides, to reveal the interaction between natural convection and EHD effect, a dimensionless number called electric convection number and fitting equations are proposed and analyzed. In addition, movements of nanoparticle and basefluid under electric field are inverse, which is beneficial to the stability of nanoparticle in the basefluid.