Análise experimental e simulação CFD de trocadores de calor casco e tubo utilizando Nanofluido de Grafeno

Abstract

In recent years, the planet has faced significant climate changes due to global warming, mainly as a result of pollutant emissions into the atmosphere. The increase in the generation of these pollutants is directly linked to the accelerated production of energy, a result of the growing demand from sectors, such as industries, over the years. Heat exchangers have faced efficiency challenges due to the low thermal conductivity of conventional fluids. With the aim of mitigating carbon emissions through more efficient heat exchangers, research indicates that suspended nanoparticles have great potential to improve heat transfer. This study comprises a comprehensive approach, combining experimental tests and numerical simulations using computational fluid dynamics (CFD) software to analyze the performance of a shell and-tube heat exchanger. In the experimental phase, tests were carried out in two parts: initially, varying the flow rates for temperatures of 40, 50 and 60 °C, using water in the hot and cold circuits. Subsequently, the experiments were repeated by replacing the water with graphene nanofluid with a concentration of 0.01% in the hot circuit, keeping water in the cold circuit. Numerical simulations replicated the experimental conditions, allowing a detailed comparison between heat exchanger performance in different configurations. The analysis covered crucial parameters such as heat transfer rate, overall heat transfer coefficient and effectiveness, aiming to evaluate the system's efficiency when using water and, subsequently, when incorporating graphene nanofluid, providing valuable insights for practical applications and optimization. of future projects. The tests showed that, even at low concentrations, the graphene nanofluid showed good results compared to water, in the shell and tube heat exchanger and that this difference tends to increase at higher temperatures. The agreement between experiments and CFD simulations showed the excellent quality of the model used. Finally, the results highlight the potential of nanofluid, even at low concentrations, and the practical usefulness of the CFD model in optimizing heat exchangers.