Comparative CFD Analysis and Optimization of Thrust Performance for Four Typical Paddlewheel Blade Shapes

Introduction: The paddle-wheel propeller has the ability to resist winding and adapt to a shallow water environment. It is widely used in inland and wetland ships. As the core factor of generating thrust, blade geometry has a critical impact on hydrodynamic performance. However, recent patents and studies have shown that the systematic comparison of blade geometry is still limited. In this study, the thrust performance of representative blade types was evaluated quantitatively to determine the optimal design. Methods: Four parametric blade models (including a traditional flat blade) were simulated by transient CFD. The Realizable k–ε turbulence model was combined with the VOF multiphase approach to resolve the air–water interaction. The interaction between rotating speed (60-350 rpm) and blade geometry is studied under strict cylindrical space constraints. Results: With the increase of rotating speed, the thrust of all blades increased, but at the same time, the stability decreased, and there was an obvious peak value. At the same speed, the wave blade produced the highest thrust and efficiency, with peak thrust 10.7% higher and efficiency 5.9% greater than the flat blade. The backward-curved and straight blades showed moderate performance, whereas the radial blade generated the lowest thrust. The high-speed rotating Curved blade enhances the splash effect. Water lift is related to efficiency, but it is not the only factor. Discussion: The computational fluid dynamics analysis of the system confirms that the corrugated blade has better thrust performance. The thrust and efficiency of wavy blades are higher than those of straight, backward curved, and radially curved blades. Conclusion: The results reveal the key interaction between speed and blade geometry, and provide practical guidance for the selection and optimization of paddle wheels. The method used is simple and effective, and has strong engineering relevance.