Application Of A Vertical Wind Tunnel To Evaluate Flow Lines Generated By Sand Filters Underdrains [aplicação De Túnel De Vento Na Avaliação De Linhas De Fluxo Geradas Por Crepinas De Filtros De Areia]

摘要

Looking for technical information to improve the hydraulic efficiency in sand filters during the filtering and backwash processes, this project had the objective to evaluate a teaching wind tunnel as a reliable method to visualize and characterize flow lines distribution generated by the interaction of a specific model of underdrain with different flow velocities.The experiment was performed by installing a commercial underdrain model, cylinder type, in an experimental section specially constructed to be coupled to a vertical wind tunnel.Three flow rate values were simulated in the tunnel, obtaining high-speed photographs.The obtained images were treated to highlight the flow lines distribution and preferred flow pathways for the filtration and backwash processes.The wind tunnel operating range was correlated by similarity with values of water flow rate in filtration processes carried out in commercial sand filters with diameters of 40, 60 and 100 cm.The obtained results validated the proposed methodology, allowing the visualization and analysis of the underdrain geometry effects on the generated flow lines, for both filtration and backwash processes.