نمذجة الحاجز في حوض الترسيب بمنهجية ديناميك الموائع الحاسوبي

Abstract EN

Gravity sedimentation is widely used in water purification plants to remove suspended solids.

The problem is that the detention-time is not enough to achieve the efficient removal of suspended solids, this is due to the formation of water eddies that cause water exit the tank too quickly (short-circuiting).

This research is an analytical work uses the ANSYS FLUENT program.

Using CFD methodology, which is the abbreviation of Computational Fluid Dynamics.

It depends on the method of finite elements, and the experimental approach through a laboratory study of a rectangular sedimentation basin equipped with a baffle.

The research objectives are 1) to find the best ratio d / L, where d is the distance of baffle from the inlet and L is the length of the basin of seven variable proportions (d / L = 0.1, 0.12, 0.125, 0.13, 0.14, 0.15 and 0.2).

2) Studying the installation of the baffle for nine variable angles, (θ = 30 °, 45 °, 60 °, 75 °, 90 °, 105 ° , 120 °, 135 ° and 150 °).3) Determine the optimum angle θ to the horizon.

The research concluded that 1) The best compatibility ratio d / L = 0.125 where the value of the eddies was 6.23 ·10-3 pa.s.

This corresponds to the sedimentation efficiency of 88.72%.

2) The best angle to fix the baffle is 60 ° to the horizon; the value was 6.162 ·10-3 pa.s.

This corresponds to the sedimentation efficiency of 89.18%.

When baffle is not provided, the value of eddies was 40.01 ·10-3 pa.s.

This corresponds to the sedimentation efficiency of 54.36%.

The efficiency has decreased about 34.5%.

Results showed agreement between Laboratory studies and the analytical study with a CFD methodology