Author(s): Juan T. Garcia Bermejo; Luis G. Castillo; Jose M. Carrillo

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Keywords: Coanda screens; Tilted wedge wire; Gap clogging; Suspended sand

Abstract: This work studies the clear water and the flow with sand transport over two Coanda effect screens with wedge wire of 1.6 and 2.4 mm width, slot openings of 0.4 and 1.0 mm, and 5º of tilt angle. The experiments were carried out in a 0.5 m wide flume with flowrates between 16.66 and 72.22 l/s/m, and sand dosage between 1.24 and 2.5 g/l. Clear water flows were also compared with computational fluid dynamic simulations carried out with FLOW-3D® software and the Coanda spreadsheet developed by Wahl (2001, 2013), showing an adequate agreement. The flow with sand transport, when pass over the screens, showed remarkable results from the point of view of the screens operation: i) no clogging in the gaps of the screen was observed, with same wetted lengths than in clear water flows experiments; ii) due to the rounded characteristics of the tested sand, a large quantity of the sand was found in the derived sand material with mesh sieves sizes higher than the screen gaps; iii) large quantity of the sand derived came from the accumulation of sand in the remaining parts of the screen when the incoming flowrate was lower than the screen intake capacity.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022228

Year: 2022