Investigation of Hydraulic Characteristics of Vertical Drops with Screens and Gradually Wall Expanding

Abstract

In the present study, we investigated the hydraulic Characteristics of vertical Drops with Screens and the Gradually Wall Expanding in downstream using Flow-3D software. For this purpose, two porosity ratio of the screens of 40 and 50%, 5 gradually expanding with 3 vertical Drops heights in the specified discharge range were used. VOF fluid volume component method to simulate free surface flow and RNG and k-ε models for turbulence were used. The validation was performed by comparing the pool depth with the laboratory results. It was found that the numerical results are closer to the experimental results with the RNG turbulence model than k-ε. Also, by increasing the drop height from 15 to 25 cm, the energy dissipation due to the jet floor impact intensity increases and the pool depth decrease. The highest energy dissipation for 25 cm height was 51.60% and the lowest for 15 cm height was 44.25%. It was observed that for a constant drop height with increasing discharge, the energy dissipation decreased and the pool depth increased. The Gradually Wall Expanding causes turbulence on the edges and a Non-uniform distribution of the downstream depth and by increasing the pool and downstream depths it causes a 25% increase in energy dissipation. The presence of screens downstream of the drop increases of the pool depth, downstream depth, and also increases the energy dissipation by 44%. It was found that the simultaneous use of Gradually Wall Expanding and screens in downstream of the drops resulted in a 46% increase in energy dissipation and a decrease in pool and downstream depths. In the end, it was proved that the participatory share of screens is greater than the Gradually Wall Expanding, and the simultaneous use of the screens and the Gradually Wall Expanding can increase the participatory share of energy dissipation by up to 33.5%.

Keywords

• Vertical Drop
• Porosity ratio
• Turbulence Models
• Gradually Wall Expanding
• Flow-3D.

Figure Investigation of Hydraulic Characteristics of Vertical Drops with Screens and Gradually Wall Expanding with FLOW3D Software

Abstract

In the present study, we investigated the hydraulic Characteristics of vertical Drops with Screens and the Gradually Wall Expanding in downstream using Flow-3D software. For this purpose, two porosity ratio of the screens of 40 and 50%, 5 gradually expanding with 3 vertical Drops heights in the specified discharge range were used. VOF fluid volume component method to simulate free surface flow and RNG and k-ε models for turbulence were used. The validation was performed by comparing the pool depth with the laboratory results. It was found that the numerical results are closer to the experimental results with the RNG turbulence model than k-ε. Also, by increasing the drop height from 15 to 25 cm, the energy dissipation due to the jet floor impact intensity increases and the pool depth decrease. The highest energy dissipation for 25 cm height was 51.60% and the lowest for 15 cm height was 44.25%. It was observed that for a constant drop height with increasing discharge, the energy dissipation decreased and the pool depth increased. The Gradually Wall Expanding causes turbulence on the edges and a Non-uniform distribution of the downstream depth and by increasing the pool and downstream depths it causes a 25% increase in energy dissipation. The presence of screens downstream of the drop increases of the pool depth, downstream depth, and also increases the energy dissipation by 44%. It was found that the simultaneous use of Gradually Wall Expanding and screens in downstream of the drops resulted in a 46% increase in energy dissipation and a decrease in pool and downstream depths. In the end, it was proved that the participatory share of screens is greater than the Gradually Wall Expanding, and the simultaneous use of the screens and the Gradually Wall Expanding can increase the participatory share of energy dissipation by up to 33.5%.

Keywords

• Vertical Drop
• Porosity ratio
• Turbulence Models
• Gradually Wall Expanding
• Flow-3D.

References

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