A high-efficiency dual-impact horizontal rotor wave energy converter: Design, analysis, and experimental tests

• A novel dual-impact horizontal rotor wave energy converter was designed. • The optimal number of blades for the horizontal rotor was determined through numerical simulation. • Rotor speed was identified as having the greatest impact on the device's startup performance. • Tank and sea trials were conducted to validate the device's power generation performance. To tackle the challenge of low power generation efficiency of wave energy converters in short-period, low-wave-height sea conditions, this study innovatively proposes a dual-impact horizontal rotor wave energy converter (DHRWEC) system. The system employs a horizontal rotor, designed based on involute principles, as its core component to efficiently capture wave energy through co-rotational motion. The VOF method was employed, and wave types were selected based on wave numerical theory. The Realizable k − ε turbulence model was selected to establish a numerical wave tank. In the numerical wave tank, the variations in rotor speed and torque for different blade counts were studied, revealing that a blade count of 22 yielded relatively optimal rotor speed and torque, preliminarily determining 22 as the blade count. A physical model was constructed, and wave flume experiments were conducted under short-period, low-wave-height conditions. Experiments show that rotor speed is a critical factor affecting energy conversion efficiency during stable operation, particularly excelling under short wave periods (1.9 s) and low wave heights (0.10 to 0.14 m). An engineering prototype was manufactured, and sea trial experiments were conducted. Sea trial results show that the DHRWEC system achieved a power generation efficiency of 21.33 % under test conditions, significantly outperforming conventional devices. Numerical simulations and experiments collectively validate its superior energy conversion performance.