Page - 190 - in Book of Full Papers - Symposium Hydro Engineering

the weight of sediments entering the flushing orifice, and WB is the weight of sediments on the basin floor. Also, to show the sediment washing rate of the floor, parameter G' was used: ' ' )( ' B BBG      (4) Which G' is sediment washing efficiency of the basin floor, η'B is settling efficiency of the basin floor without curvature submerge vanes and ηB is settling efficiency of the basin floor with curvature submerge vanes. First, initial tests were conducted without vanes on the floor with sediment. These tests were done with discharges of 45 and 37 l/s. The two tests were performed as a benchmark for comparing, analyzing, and determining the effectiveness of the modes with and without curvature submerge vanes. In these tests, the total efficiency of the vortex settling basin was obtained 93.66 and 95.76% for discharges of 37 and 45 l/s, respectively. In the presented results, R0 and S0 represent tests without curvature submerge vanes. R0 means without arrangement and S0 means without radial sections. (a) (b) Figure 11 Total efficiency of the vortex settling basin in a) discharge of 37 l/s ,b) discharge of 45 l/s In Figure 11, according to changes in radial sections of vanes and discharge, it was observed that curvature submerge vanes have a little impact on total efficiency of the vortex settling basin. Overall, for discharge of 37 and 45 l/s, they increased total efficiency of the basin in some arrangements by 0.51-4.68% and decreased it in some arrangements by 0.47- 11.45%. The reduction of total efficiency occurred in the discharge of 45 l/s due to the reduction in the efficiency of the basin in the floor. The insertion of submerge vanes in the floor of the vortex settling basin caused significant changes in the share percent of sediments settled in each part of the basin so that these vanes increased the floor efficiency and decreased the orifice efficiency in some arrangements, so these arrangements are not desirable. In some arrangements, the floor efficiency decreased and the orifice efficiency increased. So in these arrangements, the goal which was sediment washing of the basin 190