Parameters affecting forced convection enhancement in ferrofluid cooling systems

Over the last decade, lots of research works showed that ferrofluids could have great interests in thermal systems. However, convective heat transfer coefficient and pressure drop in such systems are very sensitive to many physico-chemical and geometrical parameters which must be well adjusted. In this paper, several key parameters are studied in the range of 100 < Re < 2500 such as magnetic field density, length of the magnetic source, mass flow rate and particle concentration. The thermal-hydraulic behaviors of a ferrofluid and its carrier fluid are also compared regarding the hydraulic power which is required to cool the system. This study shows that the ferrofluids application in thermal systems is the best when the Reynolds number is low. Furthermore, it seems that the best thermal-hydraulic behaviors are obtained when the ferrofluid is magnetically saturated, the magnetic field is perpendicular to the heat flux and the magnetic source is short and located in the thermally developed region of the fluid flow.