Enhancement of Heat Transfer Coefficient by using Fe₂O₃-Water Nanofluids

Research efforts have been made to increase the heat transfer rate, energy, and efficiency. Some of these efforts include the application of fins, compact heat exchangers, microchannel, and many others. Recently, nanofluids have been introduced to enhance the heat transfer rate of the heat transfer fluids by adding a certain concentration of nanoparticles into the heat transfer media. Most of the work that has been published in the literature focuses on measuring the thermal conductivity of the nanofluid or measuring the overall heat transfer coefficient. Among the efforts for enhancement of heat transfer the application of additives to liquids is noticeable (Bergles, 1973; Ahuja, 1975). Choi (1995) was the first who studied the enhancement of the nanoparticles on the heat transfer coefficient and showed that the nanoparticles could considerably affect the thermal conductivity of the nanofluid to increase. Since Choi is work (Choi, 1995), various studies have been conducted on nanofluids and these studies shown that nanofluids increase heat transfer properties and stability while reducing costs, clogging, and energy required to pump the fluid. Heris et al. (2006) found that the heat transfer coefficient increased as the volume concentration of the nanofluids increased when the fluid was composed of water and metal oxides. In the present study, effects of Fe₂O₃/water on the nanofluid\u27s heat transfer and thermal conductivity will be discussed. The experimental investigations are done to study heat transfer performance of the nanofluid at the entrance region under laminar flow condition varying the particle size and volume concentration of nanoparticles