Reaction cross-flow turbine for small hydropower plants: Flow profile design and CFD analysis

Abstract

Harnessing hydropower efficiently is crucial for sustainable energy production. Traditional impulse Cross-Flow turbines do not fully utilize the available hydraulic head, limiting their effectiveness in small-scale hydropower. The Reaction Cross-Flow turbine introduced in this study overcomes this limitation by operating as a reaction turbine, enabling full head utilization at a given site. This approach increases energy extraction and expands the applicability of Cross-Flow technology especially in run-of-river hydropower plants. This study presents a novel design approach for a Reaction Cross-Flow turbine, focusing on performance and structural optimization. A computational methodology was developed and applied to a turbine with a flow rate of 120 l/s and a head of 5.5 m. Transient numerical simulations in Ansys CFX validated the design, demonstrating a hydraulic efficiency of 79.43 %, with further potential for improvement. The resulting turbine features a compact and simplified construction compared to existing designs. This research encourages further optimization of key design aspects, such as blade geometry, cavitation control, and outlet channel configuration. The findings suggest promising directions for future studies, including the adaptation of the turbine for reverse operation. The proposed design framework serves as a foundation for advancing Reaction Cross-Flow turbine technology and improving hydropower efficiency.