Experimental correlations for Nusselt number and friction factor of nanofluids

The recent developments in nanotechnology have generated a lot of interest for researchers, scientists and engineers. By using nanotechnology, the preparation of high thermal conductivity fluids called nanofluids is possible and they may be used in heat exchange devices. The nanofluids are dilutions of nanometer sized particles in single-phase fluids of water, oil, and ethylene glycol, etc. The nanofluids offer the great advantage of heat transfer over the single-phase fluids. The lower dispersion of nanoparticles in single-phase fluids can significantly improve the thermal transport properties. This chapter addresses the available experimental correlations for Nusselt number and friction factor while the nanofluids flow in a tube under laminar and turbulent flow conditions. The Nusselt number and friction factor correlations are important while the nanofluids flow in a tube because of not valid of the available single-phase fluids correlations. Hence, this chapter gives the developed Nusselt number and friction factor correlation of various nanofluids and also factors affecting the development of correlations. The wide range of literature related to the experimental correlations in the laminar and turbulent flow is discussed.