EXPERIMENTS OF GEOMETRIC SHAPE OF SEDIMENT TRAP RECTANGULAR AND VORTEX SETTLING DESILTING BASIN

Abstract

Modernising irrigation is a top priority in Indonesia, with managing irrigation water supply services effectively and efficiently, particularly in providing value to farmers. Sediment traps are an essential component of the head structure in irrigation. Vortex Settling Desilting Basins (VSDB) have inherent advantages over other types of sediment-removal desilting basins. The experiments were conducted under three different discharge scenarios, and three-dimensional flow velocities were measured. The streamlines and velocity vectors in the horizontal superimposed sections were drawn and analysed then for the incipient motion of sediment. This study presents the results of experimental research that was accomplished in a VSDB to observe the slope orifice chamber with 1:10, 1:5 and 1:2. The method used numerical methods with CFD simulations by Ansys R.21 2020 (student version) to approach geometric shapes then laboratory experiments with a model scale 1:40 prototype to an undistorted 3-D physical model. Comparing the magnitude of the velocity and streamlined path in horizontal sections with the occurrence of secondary in radial sections revealed that the flow in the vortex direction plays a higher role in the removal efficiency of the desilting basin. As a result, by comparing the performance of rectangular shapes with the same hydraulic parameters, the slope orifice chamber of 1:5 is more effective in case of deposition and removal than another slope chamber. Eleven times running, it settled 84.90% of the sediment fraction and left a sediment fraction of 12.10%, higher than the effectiveness of the performance of sediment traps with a rectangular shape.