Amélioration des performances thermo-hydrauliques d'un échangeur de chaleur à courant croisé en utilisant des nanofluides.

Abstract

Cross-flow heat exchangers are widely used in various industrial sectors due to their compact size and efficiency. They are found in numerous applications: vehicle radiators, air conditioning systems, heat recovery in canteens and hospitals, as well as the food processing industry, where they are valued for their compactness and relatively low cost. However, their performance is often limited by the thermophysical properties of conventional heat transfer fluids. In this context, this thesis aims to study the impact of using nanofluids on the thermohydraulic performance of a cross-flow heat exchanger. Particular attention is paid to the comparative analysis between a conventional fluid (water) and a water-based nanofluid containing aluminum oxide (Al₂O₃) nanoparticles at a given volume fraction. The study relies on the use of theoretical models and fundamental relationships of heat transfer and fluid mechanics, particularly LMTD methods, as well as the analysis of hydrodynamic parameters such as Reynolds and Nusselt numbers. The calculation methodology is based on the use of commercial CFD software (ANSYS Fluent) using the finite volume method. This method allows for the solution of the conservation equations for mass, momentum, and energy. The expected results will allow for the evaluation of the thermal gain provided by nanofluids, the analysis of their impact on pressure losses, and the determination of optimal conditions for improving the overall performance of the heat exchanger. Thus, this work contributes to improving the energy efficiency of thermal systems by proposing innovative solutions based on the use of nanofluids.