Evaluation navigation controlled gate of aging spillway on cavitation damage

Area of Science:

• Civil Engineering
• Fluid Dynamics
• Materials Science

Background:

• Aging spillways face abrasion and cavitation risks from high-speed water flow, potentially compromising dam safety.
• Surface irregularities on concrete exacerbate erosion problems, necessitating urgent rehabilitation efforts in dam safety projects.

Purpose of the Study:

• To quantitatively analyze cavitation risk on the Chay 5 spillway's aging concrete surface using a 3D Computational Fluid Dynamics (CFD) model.
• To compare the effectiveness of the cavitation index (σ) and the gasification index (β) in assessing cavitation risk.

Main Methods:

• Utilized a 3D CFD model to simulate various operational scenarios of the Chay 5 spillway.
• Employed the cavitation index (σ) and the gasification index (β) to evaluate cavitation potential.
• Investigated the impact of different gate opening heights on cavitation risk.

Main Results:

• Extreme flood cases showed low cavitation risk (σ and β exceeded critical thresholds).
• Controlled gate scenarios indicated low σ but considerable cavitation risk (β < 0.8).
• Opening heights of 100 cm and 400 cm presented the highest cavitation risks in specific spillway areas.

Conclusions:

• The gasification index (β) provides a more comprehensive cavitation risk assessment for surfaces with irregularities compared to the cavitation index (σ).
• Rehabilitation with specialized anti-shrinkage, high abrasion resistance mortar significantly reduces cavitation risk.
• Surface smoothing through rehabilitation enhances spillway longevity and safety.