Performance analysis of water based CuO nanofluids in a plate heat exchanger

In recent years, it is seen that there is a significant increase in usage of the thermal systems with nano-particle fluids. It may be understood from the literature on the subject that the nano particle fluids which are known as nanofluids are used in various heat transfer systems due to their advantages. Their most outstanding feature is to enhance heat conduction and they have been replacing by the classical fluids as a working fluid in micro channels, heating installations and other technical applications where heat transfer is important. Although nanofluids enhance the heat transfer by increasing additive ratio of nano-particles compared to base fluids, it is well known that their viscosity increase and specific heat values decrease by increasing additive ratio. In addition, it has been revealed by the studies in the literature that thermal conductivity of nanofluids increases with increasing temperature and the other characteristics are also affected by temperature. In this thesis, some thermophysical characteristics of water based CuO nanofluids such as thermal conductivity, specific heat, density are analyzed experimentally as well as micro-structure, suspension time, agglomeration and effects of additives by additive ratio of nano-particles. In addition, the thermal and hydrodynamic performance of a plate heat exchanger in a modeled heating system have also been analyzed and some new correlations have been proposed. Some of the experimental studies were performed in the labs of Karadeniz Technical University. The nanofluids were prepared by a magnetic stirrer. The thermal conductivity of the nanofluids were measured by a calibrated experimental apparatus which the nanofluids were kept in a narrow gap. The micro-structure examinations were made under an appropriate SEM microscope and the evaluations were made on the images of the micro-structures. The other properties of nanofluids in the plate exchanger have been measured by various comparative methods and the results are compared to other studies in the literature. Key Words: Nanofluids, CuO, Heat exchanger, Correlation