Hydraulic Optimization of Shaft Hydropower Plant Intake Configurations Using 3D-CFD: the At-Bashy Case, Kyrgyzstan

Area of Science:

• Hydropower Engineering
• Environmental Fluid Mechanics
• Renewable Energy Systems

Background:

• Shaft hydropower plant (SHPP) modules integrated into weirs offer compact, low-head generation.
• Site-specific constraints and operations impact SHPP intake hydraulics and ecological performance.
• Optimizing SHPP intake design is crucial for balancing energy production and environmental impact.

Purpose of the Study:

• To develop and apply a 3D CFD-based hydraulic optimization framework for SHPP intakes.
• To evaluate the impact of trash rack length and submergence on fish-relevant hydraulic indicators.
• To identify optimal intake configurations for the At-Bashy demonstration site.

Main Methods:

• A structured, three-dimensional Computational Fluid Dynamics (CFD) framework was employed.
• Nine intake configurations were systematically evaluated by varying rack length and submergence.
• Fish-relevant hydraulic indicators, including velocity components and free-surface variability, were quantified.

Main Results:

• Increased submergence reduced extreme downward velocities and homogenized near-rack flow.
• Increased rack length lowered average downward flow deflection.
• Upstream flow asymmetry led to localized flow separation and heterogeneous velocity cores, emphasizing site-specific needs.

Conclusions:

• Optimal SHPP intake design necessitates site-adapted numerical evaluation, not generalized empirical rules.
• A 7m rack length with 2.35-2.85m submergence offers a balanced compromise for ecological and economic factors.
• The presented CFD framework provides a transferable methodology for SHPP intake optimization.