Effect of synchronized and unsynchronized boundary temperature modulation on the regulation of heat transfer in a ferrofluid with Fe3O4 nanoparticles

Abstract

Abstract Linear and non-linear analysis was carried out for a temperature modulated Rayleigh-Bénard ferroconvection (RBF) problem using Lorenz and Ginzburg-Landau models. The parallel and horizontal plates of infinite extension enclosing the ferrofluid (with nanosized Fe3O4 - magnetite), is cooled from the top and heated from the bottom and is exposed to an exterior static magnetic field which manipulates the flow of a ferrofluid. The Lorenz model in its linear form manifests the stationary Rayleigh number expression, whereas the nonlinear form of the model leads to Ginzburg-Landau equation determining the amplitude, which aids to quantify the amount of heat transfer in ferrofluids with the effect of temperature modulation. The influence of various parameters like Lewis number, concentration Rayleigh number, ferromagnetic parameters on the onset of ferroconvection has been discussed in detail using marginal stability curves. On the other hand, the effect of different parameters like ferro-nanoparticle volume fraction, modulation frequency, phase angle, temperature modulation on heat transfer in ferrofluids has been analyzed and represented graphically.