Análise topológica e inferência para otimização de longevidade operacional de permutador térmico assimétrico

Abstract

The heat exchanger, a device responsible for energy transfer between fluids with different temperatures, is critical in industrial applications, as its proper utilization ensures a favorable financial balance for industrial plants, considering that energy costs represent a significant portion of operational expenses. Additionally, this equipment incurs high acquisition, installation, and maintenance costs, necessitating various measures to extend its operational lifespan against its accounting depreciation. This study evaluates the topology of a shell-and-U-tube heat exchanger, aiming to extend its campaign time, given its fundamental role in industries, particularly in petrochemical applications. Numerical simulations were conducted using Computational Fluid Dynamics (CFD) with the open-source software OpenFOAM v.2406 to analyze tube wear under three different scenarios. The simulations were performed under simplified conditions to reduce computational costs, assuming airflow as a Newtonian incompressible fluid and applying the RAS turbulence model while excluding thermal profile evaluation to isolate other variables. Scenario 1 simulated real operating conditions with the original design geometry, showing significant deterioration in the first rows of tubes due to high shear stress, validating the simulation's applicability to the studied case. Scenario 2, considering a reversed tube bundle configuration, demonstrated a more uniform stress redistribution, potentially extending the equipment’s operational lifespan. Scenario 3, involving three dimensionally identical baffles, exhibited a localized stress reduction in recirculation zones by up to 50%, but also presented stress increases in critical areas by up to 35%, alongside compromised thermal efficiency. CFD proved to be an effective tool for identifying strategies to enhance the operational longevity of heat exchangers. Future experimental research is recommended to validate the assumptions and optimize the equipment’s design and maintenance, ensuring efficient and sustainable operation.