Advances in high power technology are demanding size reduction of thermal systems resulting in constrained spaces for increased heat transfer. This has led to thermal management problems in emerging systems which have defied solution by conventional cooling methods. Due to recent developments in nanotechnology, a new class of heat transfer fluids called nanofluids was discovered. A nanofluid is a solid-liquid mixture produced by dispersing metallic nanoparticles in a liquid to enhance the heat transfer performance. Experiments have shown that nanofluids have substantial higher thermal conductivities compared to the base fluids. This application of nanometer-sized particles in liquids holds huge prospects for confronting cooling problems in thermal systems. This paper summarizes the explanations that have been presented for the enhanced thermal conductivity of nanofluids, the methods of preparation as well as recent and important patents on nanofluids heat transfer. It also identifies areas for further research. This review indicates that exploitation of nanofluids could lead to development of coolants that can be applied in thermal systems leading to remarkable impact in many sectors especially energy and transportation. Also, the principles of nanoparticles in biofluids can be applied to drug delivery in body tissues thus providing new medical treatment methods.
Keywords: Nanofluids, nanoparticle, heat transfer, thermal energy transfer, thermal conductivity
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