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Trap efficiency of vortex settling chamber for exclusion of fine suspended sediment particles in irrigation canals
Author(s) -
Keshavarzi Ali Reza,
Gheisi Ali Reza
Publication year - 2006
Publication title -
irrigation and drainage
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 38
eISSN - 1531-0361
pISSN - 1531-0353
DOI - 10.1002/ird.263
Subject(s) - settling , sediment , flushing , deposition (geology) , vortex , hydrology (agriculture) , environmental science , sedimentation , volumetric flow rate , inlet , suspended load , particle (ecology) , geology , environmental engineering , sediment transport , mechanics , geotechnical engineering , geomorphology , physics , oceanography , medicine , endocrinology
Deposition of sediment particles in irrigation canals is an important problem in water conveyance systems. The vortex settling chamber is used to exclude sediment particles from the diverted water. This type of chamber is self‐flushing during the operation and compared to the usual settling basin, it is very efficient and economical. In this study, to improve trap efficiency, the vortex settling chamber was tested for fine sediment particles. To feed sediment particles at a constant rate, a new sediment feeder was designed based on the sand‐clock idea. The new sediment feeder discharges the sediment particles into the flow with a completely steady rate. The sediment feeding rate was selected with a constant rate of 70.5 g s −1 . The sediment size was also selected to be between 0.074 and 0.30 mm. To collect the sediment particles from the flushing orifice and overflow weir during the experimental tests, the excluded sediments were trapped in two fabric bags and weighed accurately after drying. The model was tested for anticlockwise flow condition. It was found that the trap efficiency of the vortex settling chamber was about 60% for the particle size used in this study. To understand the flow structure inside the model with clear water flow, the velocity of the flow in three components was measured using ADV. It was found that a deflector should be placed upon the inlet jet. The model was tested with the deflector in the anticlockwise direction. It was found that the central air core was diverted from its proper position and the trap efficiency decreased. In order to stabilize the central air core above the central orifice another test was performed with the deflector in the clockwise direction. It was found that trap efficiency of the vortex settling basin increased to 68 % for the above particle size. Copyright © 2006 John Wiley & Sons, Ltd.