2025 Volume 53 Issue 10 Pages 594-603
This study investigates the influence of the cavity opening in cross-flow turbines on turbine performance and pressure fluctuations at the nozzle tip, while also examining the underlying mechanisms causing variations in turbine characteristics depending on the opening range. The results indicate that the cavity aperture range significantly affects the flow and pressure fields as well as the torque generation in the runner. Specifically, the cavity opening influences the static pressure within the cavity, and variations in the pressure differential between the pressure side and the suction side of the blade in the cavity region impact torque generation and overall turbine performance. Additionally, a positive correlation is observed between the nozzle tip pressure and the static pressure inside the cavity. To minimize the width of the static pressure drop at the nozzle tip, it is effective to set the aperture range such that the blades simultaneously align with the upper and lower edges of the cavity. Furthermore, within the opening range, reverse flow occurs between the blades, affecting the through-flow angle in the runner and the outflow distribution at the runner exit. These findings provide insights into optimizing the cavity opening to enhance cross-flow turbine performance.
