Research on Flow and Energy Characteristics of Counter-Rotating Horizontal Axis Tidal Turbine

Abstract

The counter-rotating horizontal axis tidal turbine exhibits a pronounced advantage in harnessing tidal currents, attributed to its enhanced power generation capabilities and minimal environmental impact. In this research, numerical investigations are conducted on a counter-rotating horizontal axis tidal turbine to analyze the flow and energy characteristics within the wake region. The comparison of the single impeller and the counter-rotating ones reveals that the installation of the rear impeller can enhance the output power of the turbine, and the model’s predictive capability is validated through comparison with experimental data. A thorough examination of the pressure, streamline, and velocity distributions for both the single and counter-rotating impeller configurations reveals a consistent pattern of wake expansion. Subsequently, a quantitative assessment of the wake velocity distribution under four distinct operational speeds of 200rpm, 600rpm, 1200rpm, and 1800rpm is undertaken specifically for the counter-rotating impeller. The findings indicate that the rear impeller consistently exhibits a favorable effect on the improvement of velocity losses and the reduction of the rotational wake’s intensity, exhibiting superior adaptability under variable working conditions. These findings are of great significance for understanding the energy conversion mechanism and working characteristics of counter-rotating impellers, providing guidance for subsequent structural design and optimization practices.

Keywords: counter-rotating, turbine, near wake, impeller, flow characteristics