ABSTRACT
Magnetic nanofluid, often known as ferrofluid, is a stable colloidal suspension of magnetic nanoparticles having surfactant coatings in a carrier liquid. In the 1960s, Stephen Pappell at NASA first developed ferrofluid as an alternative for controlling fluids in the space. These fluids are responsive to the externally applied magnetic field even in the absence of gravitational force and have significant effects in heat transfer phenomena comparative to conventional fluids. An innovative way of enhancing the thermal conductivity of fluids is to suspend magnetic nanoparticles in it. These nanoparticles sometimes enhanced the thermal conductivity of fluids even by hundred times than that of the carrier fluids. Magnetic nanosuspensions have been of great scientific interest for their numerous applications in engineering, physical, and medical sciences for being a good heat transfer agent. Since last few decades, wide investigations supported by experiments have been made to understand the behavior of magnetic nanofluids so that they can be utilized in the fields where enhancement and lowering of heat transfer of thermal devices are paramount to improve the process performance. In this chapter, a brief about the magnetic nanofluids along with its constitutions, the cause of production, and various applications have been introduced. Further, the mathematical modeling and its solution are explained for the rotating/stationary/stretchable rotating disk problem. Magnetic nanofluids have vast applications due to their heat transfer problems in engineering and real-life problems. Some of the recent researches on the application of such smart fluids are also explained.
