A Parametric Study of Wave Interaction With a Rotor Having Hydrofoil Blades

Abstract

Our recent progress on studying wave interaction with a lift-type rotor is discussed in this paper. The particular focus is on characterization of the rotor’s unidirectional responsiveness in waves. The rotor consists of six hydrofoil blades in two sets. One blade set has three blades laid out as a vertical-axis wind turbine of the Darrieus type. The other blade set has three blades configured like a Wells turbine. In combination, the formed rotor can be driven by flows in any direction to perform unidirectional rotation about its vertically mounted shaft. This unidirectional responsiveness of the rotor also holds in waves, making the rotor a valuable device for wave energy conversion. For parametric study of the rotor, hydrofoil blades using different cross sectional profiles and chord lengths have been employed to configure the rotor. The rotor was then tested in a wave flume under various wave conditions in a freewheeling mode. Experimental results were analyzed and discussed. The yielded research findings will greatly enhance the fundamental understanding on the rotor performance in waves, and effectively guide the prototype rotor development for practical applications.

Rotors for wave energy conversion—Practice and possibilities

“…Other designs for vertical rotor based WECs follow a simplifies philosophy that avoids the reliance on any information or intervention from weather forecasting, sensing, electrical and or mechanical control. For example, a number of FIGURE 13 Vertical-axis unidirectional cyclorotors for wave energy conversion patented by Yang [25] vertical-axis rotor concepts were presented in the articles of Yang et al [10,25,[45][46][47][48]. These rotors have a number of cup blades or curve hydrofoils, as shown in Figure 13.…”

“…For example, a number of vertical‐axis rotor concepts were presented in the articles of Yang et al. [10, 25, 45–48]. These rotors have a number of cup blades or curve hydrofoils, as shown in Figure 13.…”

“…The test results of the drag-type rotors were published in [45] and, for lift-type rotors, in [47,48]. Experimental results have demonstrated unidirectional rotation of the rotors, but with noticeable fluctuations in angular velocity.…”